Drake
LeafSystem< T > Class Template Reference

A superclass template that extends System with some convenience utilities that are not applicable to Diagrams. More...

#include <drake/systems/framework/leaf_system.h>

## Public Member Functions

~LeafSystem () override

std::unique_ptr< CompositeEventCollection< T > > AllocateCompositeEventCollection () const final
Allocates a CompositeEventCollection object for this system. More...

std::unique_ptr< LeafContext< T > > AllocateContext () const
Shadows System<T>::AllocateContext to provide a more concrete return type LeafContext<T>. More...

std::unique_ptr< ContextBaseDoAllocateContext () const final
Derived class implementations should allocate a suitable concrete Context type, then invoke the above InitializeContextBase() method. More...

void SetDefaultState (const Context< T > &context, State< T > *state) const override
Default implementation: sets all continuous state to the model vector given in DeclareContinuousState (or zero if no model vector was given) and discrete states to zero. More...

void SetDefaultParameters (const Context< T > &context, Parameters< T > *parameters) const override
Default implementation: sets all numeric parameters to the model vector given to DeclareNumericParameter, or else if no model was provided sets the numeric parameter to one. More...

std::unique_ptr< ContinuousState< T > > AllocateTimeDerivatives () const override
Returns the AllocateContinuousState value, which must not be nullptr. More...

std::unique_ptr< DiscreteValues< T > > AllocateDiscreteVariables () const override
Returns the AllocateDiscreteState value, which must not be nullptr. More...

std::multimap< int, intGetDirectFeedthroughs () const final
Reports all direct feedthroughs from input ports to output ports. More...

int get_num_continuous_states () const final
Returns the dimension of the continuous state vector that has been declared until now. More...

Does not allow copy, move, or assignment
LeafSystem (const LeafSystem &)=delete

LeafSystemoperator= (const LeafSystem &)=delete

LeafSystem (LeafSystem &&)=delete

LeafSystemoperator= (LeafSystem &&)=delete

Public Member Functions inherited from System< T >
~System () override=default

void GetWitnessFunctions (const Context< T > &context, std::vector< const WitnessFunction< T > *> *w) const
Gets the witness functions active for the given state. More...

CalcWitnessValue (const Context< T > &context, const WitnessFunction< T > &witness_func) const
Evaluates a witness function at the given context. More...

System (const System &)=delete

Systemoperator= (const System &)=delete

System (System &&)=delete

Systemoperator= (System &&)=delete

std::unique_ptr< Context< T > > AllocateContext () const
Returns a Context<T> suitable for use with this System<T>. More...

std::unique_ptr< BasicVector< T > > AllocateInputVector (const InputPort< T > &input_port) const
Given an input port, allocates the vector storage. More...

std::unique_ptr< AbstractValueAllocateInputAbstract (const InputPort< T > &input_port) const
Given an input port, allocates the abstract storage. More...

std::unique_ptr< SystemOutput< T > > AllocateOutput () const
Returns a container that can hold the values of all of this System's output ports. More...

std::unique_ptr< Context< T > > CreateDefaultContext () const
This convenience method allocates a context using AllocateContext() and sets its default values using SetDefaultContext(). More...

void SetDefaultContext (Context< T > *context) const

virtual void SetRandomState (const Context< T > &context, State< T > *state, RandomGenerator *generator) const
Assigns random values to all elements of the state. More...

virtual void SetRandomParameters (const Context< T > &context, Parameters< T > *parameters, RandomGenerator *generator) const
Assigns random values to all parameters. More...

void SetRandomContext (Context< T > *context, RandomGenerator *generator) const

void AllocateFixedInputs (Context< T > *context) const
For each input port, allocates a fixed input of the concrete type that this System requires, and binds it to the port, disconnecting any prior input. More...

bool HasAnyDirectFeedthrough () const
Returns true if any of the inputs to the system might be directly fed through to any of its outputs and false otherwise. More...

bool HasDirectFeedthrough (int output_port) const
Returns true if there might be direct-feedthrough from any input port to the given output_port, and false otherwise. More...

bool HasDirectFeedthrough (int input_port, int output_port) const
Returns true if there might be direct-feedthrough from the given input_port to the given output_port, and false otherwise. More...

void Publish (const Context< T > &context, const EventCollection< PublishEvent< T >> &events) const
This method is the public entry point for dispatching all publish event handlers. More...

void Publish (const Context< T > &context) const
Forces a publish on the system, given a context. More...

const ContinuousState< T > & EvalTimeDerivatives (const Context< T > &context) const
Returns a reference to the cached value of the continuous state variable time derivatives, evaluating first if necessary using CalcTimeDerivatives(). More...

const T & EvalPotentialEnergy (const Context< T > &context) const
Returns a reference to the cached value of the potential energy (PE), evaluating first if necessary using CalcPotentialEnergy(). More...

const T & EvalKineticEnergy (const Context< T > &context) const
Returns a reference to the cached value of the kinetic energy (KE), evaluating first if necessary using CalcKineticEnergy(). More...

const T & EvalConservativePower (const Context< T > &context) const
Returns a reference to the cached value of the conservative power (Pc), evaluating first if necessary using CalcConservativePower(). More...

const T & EvalNonConservativePower (const Context< T > &context) const
Returns a reference to the cached value of the non-conservative power (Pnc), evaluating first if necessary using CalcNonConservativePower(). More...

template<template< typename > class Vec = BasicVector>
const Vec< T > * EvalVectorInput (const Context< T > &context, int port_index) const
Returns the value of the vector-valued input port with the given port_index as a BasicVector or a specific subclass Vec derived from BasicVector. More...

Eigen::VectorBlock< const VectorX< T > > EvalEigenVectorInput (const Context< T > &context, int port_index) const
Returns the value of the vector-valued input port with the given port_index as an Eigen vector. More...

int get_num_constraint_equations (const Context< T > &context) const
Gets the number of constraint equations for this system using the given context (useful in case the number of constraints is dependent upon the current state (as might be the case with a system modeled using piecewise differential algebraic equations). More...

Eigen::VectorXd EvalConstraintEquations (const Context< T > &context) const
Evaluates the constraint equations for the system at the generalized coordinates and generalized velocity specified by the context. More...

Eigen::VectorXd EvalConstraintEquationsDot (const Context< T > &context) const
Computes the time derivative of each constraint equation, evaluated at the generalized coordinates and generalized velocity specified by the context. More...

Eigen::VectorXd CalcVelocityChangeFromConstraintImpulses (const Context< T > &context, const Eigen::MatrixXd &J, const Eigen::VectorXd &lambda) const
Computes the change in velocity from applying the given constraint forces to the system at the given context. More...

double CalcConstraintErrorNorm (const Context< T > &context, const Eigen::VectorXd &error) const
Computes the norm on constraint error (used as a metric for comparing errors between the outputs of algebraic equations applied to two different state variable instances). More...

void CalcTimeDerivatives (const Context< T > &context, ContinuousState< T > *derivatives) const
Calculates the time derivatives xcdot of the continuous state xc into a given output argument. More...

void CalcDiscreteVariableUpdates (const Context< T > &context, const EventCollection< DiscreteUpdateEvent< T >> &events, DiscreteValues< T > *discrete_state) const
This method is the public entry point for dispatching all discrete variable update event handlers. More...

void CalcDiscreteVariableUpdates (const Context< T > &context, DiscreteValues< T > *discrete_state) const
This method forces a discrete update on the system given a context, and the updated discrete state is stored in discrete_state. More...

void CalcUnrestrictedUpdate (const Context< T > &context, const EventCollection< UnrestrictedUpdateEvent< T >> &events, State< T > *state) const
This method is the public entry point for dispatching all unrestricted update event handlers. More...

void CalcUnrestrictedUpdate (const Context< T > &context, State< T > *state) const
This method forces an unrestricted update on the system given a context, and the updated state is stored in state. More...

CalcNextUpdateTime (const Context< T > &context, CompositeEventCollection< T > *events) const
This method is called by a Simulator during its calculation of the size of the next continuous step to attempt. More...

void GetPerStepEvents (const Context< T > &context, CompositeEventCollection< T > *events) const
This method is called by Simulator::Initialize() to gather all update and publish events that are to be handled in StepTo() at the point before Simulator integrates continuous state. More...

void GetInitializationEvents (const Context< T > &context, CompositeEventCollection< T > *events) const
This method is called by Simulator::Initialize() to gather all update and publish events that need to be handled at initialization before the simulator starts integration. More...

optional< PeriodicEventDataGetUniquePeriodicDiscreteUpdateAttribute () const
Gets whether there exists a unique periodic attribute that triggers one or more discrete update events (and, if so, returns that unique periodic attribute). More...

std::map< PeriodicEventData, std::vector< const Event< T > * >, PeriodicEventDataComparatorGetPeriodicEvents () const
Gets all periodic triggered events for a system. More...

void CalcOutput (const Context< T > &context, SystemOutput< T > *outputs) const
Utility method that computes for every output port i the value y(i) that should result from the current contents of the given Context. More...

CalcPotentialEnergy (const Context< T > &context) const
Calculates and returns the potential energy represented by the current configuration provided in context. More...

CalcKineticEnergy (const Context< T > &context) const
Calculates and returns the kinetic energy represented by the current configuration and velocity provided in context. More...

CalcConservativePower (const Context< T > &context) const
Calculates and returns the conservative power represented by the current contents of the given context. More...

CalcNonConservativePower (const Context< T > &context) const
Calculates and returns the non-conservative power represented by the current contents of the given context. More...

void MapVelocityToQDot (const Context< T > &context, const VectorBase< T > &generalized_velocity, VectorBase< T > *qdot) const
Transforms a given generalized velocity v to the time derivative qdot of the generalized configuration q taken from the supplied Context. More...

void MapVelocityToQDot (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &generalized_velocity, VectorBase< T > *qdot) const
Transforms the given generalized velocity to the time derivative of generalized configuration. More...

void MapQDotToVelocity (const Context< T > &context, const VectorBase< T > &qdot, VectorBase< T > *generalized_velocity) const
Transforms the time derivative qdot of the generalized configuration q to generalized velocities v. More...

void MapQDotToVelocity (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &qdot, VectorBase< T > *generalized_velocity) const
Transforms the given time derivative qdot of generalized configuration q to generalized velocity v. More...

std::string GetMemoryObjectName () const
Returns a name for this System based on a stringification of its type name and memory address. More...

const InputPort< T > & get_input_port (int port_index) const
Returns the typed input port at index port_index. More...

const InputPort< T > & GetInputPort (const std::string &port_name) const
Returns the typed input port with the unique name port_name. More...

const OutputPort< T > & get_output_port (int port_index) const
Returns the typed output port at index port_index. More...

const OutputPort< T > & GetOutputPort (const std::string &port_name) const
Returns the typed output port with the unique name port_name. More...

int get_num_constraints () const
Returns the number of constraints specified for the system. More...

const SystemConstraint< T > & get_constraint (SystemConstraintIndex constraint_index) const
Returns the constraint at index constraint_index. More...

boolean< T > CheckSystemConstraintsSatisfied (const Context< T > &context, double tol) const
Returns true if context satisfies all of the registered SystemConstraints with tolerance tol. More...

void CheckValidOutput (const SystemOutput< T > *output) const
Checks that output is consistent with the number and size of output ports declared by the system. More...

template<typename T1 = T>
void CheckValidContextT (const Context< T1 > &context) const
Checks that context is consistent for this System template. More...

VectorX< T > CopyContinuousStateVector (const Context< T > &context) const
Returns a copy of the continuous state vector xc into an Eigen vector. More...

std::string GetGraphvizString (int max_depth=std::numeric_limits< int >::max()) const
Returns a Graphviz string describing this System. More...

int64_t GetGraphvizId () const
Returns an opaque integer that uniquely identifies this system in the Graphviz output. More...

void FixInputPortsFrom (const System< double > &other_system, const Context< double > &other_context, Context< T > *target_context) const
Fixes all of the input ports in target_context to their current values in other_context, as evaluated by other_system. More...

const SystemScalarConverterget_system_scalar_converter () const
(Advanced) Returns the SystemScalarConverter for this object. More...

std::unique_ptr< System< AutoDiffXd > > ToAutoDiffXd () const
Creates a deep copy of this System, transmogrified to use the autodiff scalar type, with a dynamic-sized vector of partial derivatives. More...

std::unique_ptr< System< AutoDiffXd > > ToAutoDiffXdMaybe () const
Creates a deep copy of this system exactly like ToAutoDiffXd(), but returns nullptr if this System does not support autodiff, instead of throwing an exception. More...

std::unique_ptr< System< symbolic::Expression > > ToSymbolic () const
Creates a deep copy of this System, transmogrified to use the symbolic scalar type. More...

std::unique_ptr< System< symbolic::Expression > > ToSymbolicMaybe () const
Creates a deep copy of this system exactly like ToSymbolic(), but returns nullptr if this System does not support symbolic, instead of throwing an exception. More...

Public Member Functions inherited from SystemBase
~SystemBase () override

void set_name (const std::string &name)
Sets the name of the system. More...

const std::string & get_name () const
Returns the name last supplied to set_name(), if any. More...

const std::string & GetSystemName () const final
Returns a human-readable name for this system, for use in messages and logging. More...

std::string GetSystemPathname () const final
Generates and returns a human-readable full path name of this subsystem, for use in messages and logging. More...

std::string GetSystemType () const final
Returns the most-derived type of this concrete System object as a human-readable string suitable for use in error messages. More...

void ThrowIfContextNotCompatible (const ContextBase &context) const final
Throws an exception with an appropriate message if the given context is not compatible with this System. More...

std::unique_ptr< ContextBaseAllocateContext () const
Returns a Context suitable for use with this System. More...

int get_num_input_ports () const
Returns the number of input ports currently allocated in this System. More...

int get_num_output_ports () const
Returns the number of output ports currently allocated in this System. More...

const InputPortBaseget_input_port_base (InputPortIndex port_index) const
Returns a reference to an InputPort given its port_index. More...

const OutputPortBaseget_output_port_base (OutputPortIndex port_index) const
Returns a reference to an OutputPort given its port_index. More...

int get_num_total_inputs () const
Returns the total dimension of all of the vector-valued input ports (as if they were muxed). More...

int get_num_total_outputs () const
Returns the total dimension of all of the vector-valued output ports (as if they were muxed). More...

int num_cache_entries () const
Returns the number nc of cache entries currently allocated in this System. More...

const CacheEntryget_cache_entry (CacheIndex index) const
Return a reference to a CacheEntry given its index. More...

void CheckValidContext (const ContextBase &context) const
Checks whether the given context is valid for this System and throws an exception with a helpful message if not. More...

SystemBase (const SystemBase &)=delete

SystemBaseoperator= (const SystemBase &)=delete

SystemBase (SystemBase &&)=delete

SystemBaseoperator= (SystemBase &&)=delete

const AbstractValueEvalAbstractInput (const ContextBase &context, int port_index) const
Returns the value of the input port with the given port_index as an AbstractValue, which is permitted for ports of any type. More...

template<typename V >
const V * EvalInputValue (const ContextBase &context, int port_index) const
Returns the value of an abstract-valued input port with the given port_index as a value of known type V. More...

const CacheEntryDeclareCacheEntry (std::string description, CacheEntry::AllocCallback alloc_function, CacheEntry::CalcCallback calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a new CacheEntry in this System using the least-restrictive definitions for the associated functions. More...

template<class MySystem , class MyContext , typename ValueType >
const CacheEntryDeclareCacheEntry (std::string description, ValueType(MySystem::*make)() const, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a cache entry by specifying member functions to use both for the allocator and calculator. More...

template<class MySystem , class MyContext , typename ValueType >
const CacheEntryDeclareCacheEntry (std::string description, const ValueType &model_value, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a cache entry by specifying a model value of concrete type ValueType and a calculator function that is a class member function (method) with signature: More...

template<class MySystem , class MyContext , typename ValueType >
const CacheEntryDeclareCacheEntry (std::string description, const ValueType &model_value, ValueType(MySystem::*calc)(const MyContext &) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a cache entry by specifying a model value of concrete type ValueType and a calculator function that is a class member function (method) with signature: More...

template<class MySystem , class MyContext , typename ValueType >
const CacheEntryDeclareCacheEntry (std::string description, void(MySystem::*calc)(const MyContext &, ValueType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a cache entry by specifying only a calculator function that is a class member function (method) with signature: More...

template<class MySystem , class MyContext , typename ValueType >
const CacheEntryDeclareCacheEntry (std::string description, ValueType(MySystem::*calc)(const MyContext &) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a cache entry by specifying only a calculator function that is a class member function (method) with signature: More...

DependencyTicket discrete_state_ticket (DiscreteStateIndex index) const
Returns a ticket indicating dependence on a particular discrete state variable xdᵢ (may be a vector). More...

DependencyTicket abstract_state_ticket (AbstractStateIndex index) const
Returns a ticket indicating dependence on a particular abstract state variable xaᵢ. More...

DependencyTicket numeric_parameter_ticket (NumericParameterIndex index) const
Returns a ticket indicating dependence on a particular numeric parameter pnᵢ (may be a vector). More...

DependencyTicket abstract_parameter_ticket (AbstractParameterIndex index) const
Returns a ticket indicating dependence on a particular abstract parameter paᵢ. More...

DependencyTicket input_port_ticket (InputPortIndex index)
Returns a ticket indicating dependence on input port uᵢ indicated by index. More...

DependencyTicket cache_entry_ticket (CacheIndex index)
Returns a ticket indicating dependence on the cache entry indicated by index. More...

DependencyTicket output_port_ticket (OutputPortIndex index)
(Internal use only) Returns a ticket indicating dependence on the output port indicated by index. More...

int num_discrete_state_groups () const
Returns the number of declared discrete state groups (each group is a vector-valued discrete state variable). More...

int num_abstract_states () const
Returns the number of declared abstract state variables. More...

int num_numeric_parameter_groups () const
Returns the number of declared numeric parameters (each of these is a vector-valued parameter). More...

DRAKE_DEPRECATED ("Use num_numeric_parameter_groups(). This method will be" " removed after 2/15/19.") int num_numeric_parameters() const

int num_abstract_parameters () const
Returns the number of declared abstract parameters. More...

## Protected Member Functions

LeafSystem ()
Default constructor that declares no inputs, outputs, state, parameters, events, nor scalar-type conversion support (AutoDiff, etc.). More...

LeafSystem (SystemScalarConverter converter)
Constructor that declares no inputs, outputs, state, parameters, or events, but allows subclasses to declare scalar-type conversion support (AutoDiff, etc.). More...

virtual std::unique_ptr< LeafContext< T > > DoMakeLeafContext () const
Provides a new instance of the leaf context for this system. More...

virtual void DoValidateAllocatedLeafContext (const LeafContext< T > &context) const
Derived classes that impose restrictions on what resources are permitted should check those restrictions by implementing this. More...

DoCalcWitnessValue (const Context< T > &context, const WitnessFunction< T > &witness_func) const final
Derived classes will implement this method to evaluate a witness function at the given context. More...

void AddTriggeredWitnessFunctionToCompositeEventCollection (Event< T > *event, CompositeEventCollection< T > *events) const final
Add event to events due to a witness function triggering. More...

void DoCalcNextUpdateTime (const Context< T > &context, CompositeEventCollection< T > *events, T *time) const override
Computes the next update time based on the configured periodic events, for scalar types that are arithmetic, or aborts for scalar types that are not arithmetic. More...

void GetGraphvizFragment (int max_depth, std::stringstream *dot) const override
Emits a graphviz fragment for this System. More...

void GetGraphvizInputPortToken (const InputPort< T > &port, int max_depth, std::stringstream *dot) const final
Appends a fragment to the dot stream identifying the graphviz node representing port. More...

void GetGraphvizOutputPortToken (const OutputPort< T > &port, int max_depth, std::stringstream *dot) const final
Appends a fragment to the dot stream identifying the graphviz node representing port. More...

virtual std::unique_ptr< ContinuousState< T > > AllocateContinuousState () const
Returns a ContinuousState used to implement both CreateDefaultContext and AllocateTimeDerivatives. More...

virtual std::unique_ptr< DiscreteValues< T > > AllocateDiscreteState () const
Reserves the discrete state as required by CreateDefaultContext. More...

virtual std::unique_ptr< AbstractValuesAllocateAbstractState () const
Reserves the abstract state as required by CreateDefaultContext. More...

virtual std::unique_ptr< Parameters< T > > AllocateParameters () const
Reserves the parameters as required by CreateDefaultContext. More...

virtual optional< boolDoHasDirectFeedthrough (int input_port, int output_port) const
Returns true if there is direct-feedthrough from the given input_port to the given output_port, false if there is not direct-feedthrough, or nullopt if unknown (in which case SystemSymbolicInspector will attempt to measure the feedthrough using symbolic form). More...

int DeclareNumericParameter (const BasicVector< T > &model_vector)
Declares a numeric parameter using the given model_vector. More...

template<template< typename > class U = BasicVector>
const U< T > & GetNumericParameter (const Context< T > &context, int index) const
Extracts the numeric parameters of type U from the context at index. More...

template<template< typename > class U = BasicVector>
U< T > & GetMutableNumericParameter (Context< T > *context, int index) const
Extracts the numeric parameters of type U from the context at index. More...

int DeclareAbstractParameter (const AbstractValue &model_value)
Declares an abstract parameter using the given model_value. More...

template<typename EventType >
void DeclarePeriodicEvent (double period_sec, double offset_sec)
Declares that this System has a simple, fixed-period event specified with no custom callback function, and its attribute field contains an Event<T>::PeriodicAttribute constructed from the specified period_sec and offset_sec. More...

template<typename EventType >
void DeclarePeriodicEvent (double period_sec, double offset_sec, const EventType &event)
Declares that this System has a simple, fixed-period event specified by event. More...

void DeclarePeriodicDiscreteUpdate (double period_sec, double offset_sec=0)
Declares a periodic discrete update event with period = period_sec and offset = offset_sec. More...

void DeclarePeriodicUnrestrictedUpdate (double period_sec, double offset_sec=0)
Declares a periodic unrestricted update event with period = period_sec and offset = offset_sec. More...

void DeclarePeriodicPublish (double period_sec, double offset_sec=0)
Declares a periodic publish event with period = period_sec and offset = offset_sec. More...

template<typename EventType >
void DeclarePerStepEvent (const EventType &event)
Declares a per-step event using event, which is deep copied (the copy is maintained by this). More...

template<typename EventType >
void DeclareInitializationEvent (const EventType &event)
Declares an initialization event by deep copying event and storing it internally. More...

template<class MySystem >
SystemConstraintIndex DeclareEqualityConstraint (void(MySystem::*calc)(const Context< T > &, VectorX< T > *) const, int count, const std::string &description)
Declares a system constraint of the form f(context) = 0 by specifying a member function to use to calculate the (VectorX) constraint value with a signature: More...

SystemConstraintIndex DeclareEqualityConstraint (typename SystemConstraint< T >::CalcCallback calc, int count, const std::string &description)
Declares a system constraint of the form f(context) = 0 by specifying a std::function to use to calculate the (Vector) constraint value with a signature: More...

template<class MySystem >
SystemConstraintIndex DeclareInequalityConstraint (void(MySystem::*calc)(const Context< T > &, VectorX< T > *) const, int count, const std::string &description)
Declares a system constraint of the form f(context) ≥ 0 by specifying a member function to use to calculate the (VectorX) constraint value with a signature: More...

SystemConstraintIndex DeclareInequalityConstraint (typename SystemConstraint< T >::CalcCallback calc, int count, const std::string &description)
Declares a system constraint of the form f(context) ≥ 0 by specifying a std::function to use to calculate the (Vector) constraint value with a signature: More...

virtual void DoPublish (const Context< T > &context, const std::vector< const PublishEvent< T > *> &events) const
Derived-class event handler for all simultaneous publish events in events. More...

virtual void DoCalcDiscreteVariableUpdates (const Context< T > &context, const std::vector< const DiscreteUpdateEvent< T > *> &events, DiscreteValues< T > *discrete_state) const
Derived-class event handler for all simultaneous discrete update events. More...

virtual void DoCalcUnrestrictedUpdate (const Context< T > &context, const std::vector< const UnrestrictedUpdateEvent< T > *> &events, State< T > *state) const
Derived-class event handler for all simultaneous unrestricted update events. More...

Declare continuous state variables

Continuous state consists of up to three kinds of variables: generalized coordinates q, generalized velocities v, and miscellaneous continuous variables z.

Methods in this section provide different ways to declare these, and offer the ability to provide a model_vector to specify the initial values for these variables. Model values are useful when you want the values of these variables in a default Context to be something other than zero.

If multiple calls are made to DeclareContinuousState() methods, only the last call has any effect. Also, these methods have no effect if AllocateContinuousState() is overridden (not recommended).

void DeclareContinuousState (int num_state_variables)
Declares that this System should reserve continuous state with num_state_variables state variables, which have no second-order structure. More...

void DeclareContinuousState (int num_q, int num_v, int num_z)
Declares that this System should reserve continuous state with num_q generalized positions, num_v generalized velocities, and num_z miscellaneous state variables. More...

void DeclareContinuousState (const BasicVector< T > &model_vector)
Declares that this System should reserve continuous state with model_vector.size() miscellaneous state variables, stored in a vector cloned from model_vector. More...

void DeclareContinuousState (const BasicVector< T > &model_vector, int num_q, int num_v, int num_z)
Declares that this System should reserve continuous state with num_q generalized positions, num_v generalized velocities, and num_z miscellaneous state variables, stored in a vector cloned from model_vector. More...

Declare discrete state variables

Discrete state consists of any number of discrete state "groups", each of which is a vector of discrete state variables.

Methods in this section provide different ways to declare these, and offer the ability to provide a model_vector to specify the initial values for each group of variables. Model values are useful when you want the values of these variables in a default Context to be something other than zero.

Each call to a DeclareDiscreteState() method produces another discrete state group, and the group index is returned. These methods have no effect if AllocateDiscreteState() is overridden (not recommended).

DiscreteStateIndex DeclareDiscreteState (const BasicVector< T > &model_vector)
Declares a discrete state group with model_vector.size() state variables, stored in a vector cloned from model_vector (preserving the concrete type and value). More...

DiscreteStateIndex DeclareDiscreteState (const Eigen::Ref< const VectorX< T >> &model_vector)
Declares a discrete state group with model_vector.size() state variables, stored in a BasicVector initialized with the contents of model_vector. More...

DiscreteStateIndex DeclareDiscreteState (int num_state_variables)
Declares a discrete state group with num_state_variables state variables, stored in a BasicVector initialized to be all-zero. More...

Declare abstract state variables

Abstract state consists of any number of arbitrarily-typed variables, each represented by an AbstractValue.

Each call to the DeclareAbstractState() method produces another abstract state variable, and the abstract state variable index is returned. This method has no effect if AllocateAbstractState() is overridden (not recommended).

AbstractStateIndex DeclareAbstractState (std::unique_ptr< AbstractValue > abstract_state)
Declares an abstract state. More...

Declare input ports

Methods in this section are used by derived classes to declare their output ports, which may be vector valued or abstract valued.

You should normally provide a meaningful name for any input port you create. Names must be unique for this system (passing in a duplicate name will throw std::logic_error). However, if you specify kUseDefaultName as the name, then a default name of e.g. "u2", where 2 is the input port number will be provided. An empty name is not permitted.

const InputPort< T > & DeclareVectorInputPort (variant< std::string, UseDefaultName > name, const BasicVector< T > &model_vector, optional< RandomDistribution > random_type=nullopt)
Declares a vector-valued input port using the given model_vector. More...

const InputPort< T > & DeclareAbstractInputPort (variant< std::string, UseDefaultName > name, const AbstractValue &model_value)
Declares an abstract-valued input port using the given model_value. More...

To-be-deprecated input port declarations

Methods in this section leave out the name parameter and are the same as invoking the corresponding method with kUseDefaultName as the name.

We intend to make specifying the name required and will deprecate these soon. Don't use them.

const InputPort< T > & DeclareVectorInputPort (const BasicVector< T > &model_vector, optional< RandomDistribution > random_type=nullopt)
See the nearly identical signature with an additional (first) argument specifying the port name. More...

const InputPort< T > & DeclareAbstractInputPort (const AbstractValue &model_value)
See the nearly identical signature with an additional (first) argument specifying the port name. More...

Declare output ports

Methods in this section are used by derived classes to declare their output ports, which may be vector valued or abstract valued. Every output port must have an allocator function and a calculator function. The allocator returns an object suitable for holding a value of the output port. The calculator uses the contents of a given Context to produce the output port's value, which is placed in an object of the type returned by the allocator.

Although the allocator and calculator functions ultimately satisfy generic function signatures defined in LeafOutputPort, we provide a variety of DeclareVectorOutputPort() and DeclareAbstractOutputPort() signatures here for convenient specification, with mapping to the generic form handled invisibly. In particular, allocators are most easily defined by providing a model value that can be used to construct an allocator that copies the model when a new value object is needed. Alternatively a method can be provided that constructs a value object when invoked (those methods are conventionally, but not necessarily, named MakeSomething() where Something is replaced by the output port value type).

Because output port values are ultimately stored in AbstractValue objects, the underlying types must be suitable. For vector ports, that means the type must be BasicVector or a class derived from BasicVector. For abstract ports, the type must be copy constructible or cloneable. For methods below that are not given an explicit model value or construction ("make") method, the underlying type must be default constructible.

See also
drake::systems::Value for more about abstract values.

A list of prerequisites may be provided for the calculator function to avoid unnecessary recomputation. If no prerequisites are provided, the default is to assume the output port value is dependent on all possible sources. See DeclareCacheEntry for more information about prerequisites.

Output ports must have a name that is unique within the owning subsystem. Users can provide meaningful names or specify the name as kUseDefaultName in which case a name like "y3" is automatically provided, where the number is the output port index. An empty name is not permitted.

template<class MySystem , typename BasicVectorSubtype >
const OutputPort< T > & DeclareVectorOutputPort (variant< std::string, UseDefaultName > name, const BasicVectorSubtype &model_vector, void(MySystem::*calc)(const Context< T > &, BasicVectorSubtype *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a vector-valued output port by specifying (1) a model vector of type BasicVectorSubtype derived from BasicVector and initialized to the correct size and desired initial value, and (2) a calculator function that is a class member function (method) with signature: More...

template<class MySystem , typename BasicVectorSubtype >
const OutputPort< T > & DeclareVectorOutputPort (variant< std::string, UseDefaultName > name, void(MySystem::*calc)(const Context< T > &, BasicVectorSubtype *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares a vector-valued output port by specifying only a calculator function that is a class member function (method) with signature: More...

const OutputPort< T > & DeclareVectorOutputPort (variant< std::string, UseDefaultName > name, const BasicVector< T > &model_vector, typename LeafOutputPort< T >::CalcVectorCallback vector_calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
(Advanced) Declares a vector-valued output port using the given model_vector and a function for calculating the port's value at runtime. More...

template<class MySystem , typename OutputType >
const OutputPort< T > & DeclareAbstractOutputPort (variant< std::string, UseDefaultName > name, const OutputType &model_value, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares an abstract-valued output port by specifying a model value of concrete type OutputType and a calculator function that is a class member function (method) with signature: More...

template<class MySystem , typename OutputType >
const OutputPort< T > & DeclareAbstractOutputPort (variant< std::string, UseDefaultName > name, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares an abstract-valued output port by specifying only a calculator function that is a class member function (method) with signature: More...

template<class MySystem , typename OutputType >
const OutputPort< T > & DeclareAbstractOutputPort (variant< std::string, UseDefaultName > name, OutputType(MySystem::*make)() const, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
Declares an abstract-valued output port by specifying member functions to use both for the allocator and calculator. More...

const OutputPort< T > & DeclareAbstractOutputPort (variant< std::string, UseDefaultName > name, typename LeafOutputPort< T >::AllocCallback alloc_function, typename LeafOutputPort< T >::CalcCallback calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
(Advanced) Declares an abstract-valued output port using the given allocator and calculator functions provided in their most generic forms. More...

To-be-deprecated output port declarations

Methods in this section leave out the name parameter and are the same as invoking the corresponding method with kUseDefaultName as the name.

We intend to make specifying the name required and will deprecate these soon. Don't use them.

template<class MySystem , typename BasicVectorSubtype >
const OutputPort< T > & DeclareVectorOutputPort (const BasicVectorSubtype &model_vector, void(MySystem::*calc)(const Context< T > &, BasicVectorSubtype *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

template<class MySystem , typename BasicVectorSubtype >
const OutputPort< T > & DeclareVectorOutputPort (void(MySystem::*calc)(const Context< T > &, BasicVectorSubtype *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

const OutputPort< T > & DeclareVectorOutputPort (const BasicVector< T > &model_vector, typename LeafOutputPort< T >::CalcVectorCallback vector_calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

template<class MySystem , typename OutputType >
std::enable_if_t<!std::is_same< OutputType, std::string >::value, const OutputPort< T > & > DeclareAbstractOutputPort (const OutputType &model_value, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

template<class MySystem , typename OutputType >
const OutputPort< T > & DeclareAbstractOutputPort (void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

template<class MySystem , typename OutputType >
const OutputPort< T > & DeclareAbstractOutputPort (OutputType(MySystem::*make)() const, void(MySystem::*calc)(const Context< T > &, OutputType *) const, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

const OutputPort< T > & DeclareAbstractOutputPort (typename LeafOutputPort< T >::AllocCallback alloc_function, typename LeafOutputPort< T >::CalcCallback calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
See the nearly identical signature with an additional (first) argument specifying the port name. More...

Declare witness functions

Methods in this section are used by derived classes to declare any witness functions useful for ensuring that integration ends a step upon entering particular times or states.

In contrast to other declaration methods (e.g., DeclareVectorOutputPort(), for which the System class creates and stores the objects and returns references to them, the witness function declaration functions return heap-allocated objects that the subclass of leaf system owns. This facilitates returning pointers to these objects in System::DoGetWitnessFunctions().

template<class MySystem >
std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function; and with no event object. More...

std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, std::function< T(const Context< T > &)> calc) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function; and with no event object. More...

template<class MySystem >
std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, void(MySystem::*publish_callback)(const Context< T > &, const PublishEvent< T > &) const) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and publish event callback function for when this triggers. More...

template<class MySystem >
std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, void(MySystem::*du_callback)(const Context< T > &, const DiscreteUpdateEvent< T > &, DiscreteValues< T > *) const) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and discrete update event callback function for when this triggers. More...

template<class MySystem >
std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, void(MySystem::*uu_callback)(const Context< T > &, const UnrestrictedUpdateEvent< T > &, State< T > *) const) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and unrestricted update event callback function for when this triggers. More...

template<class MySystem >
std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, T(MySystem::*calc)(const Context< T > &) const, const Event< T > &e) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function, and with an object corresponding to the event that is to be dispatched when this witness function triggers. More...

std::unique_ptr< WitnessFunction< T > > DeclareWitnessFunction (const std::string &description, const WitnessFunctionDirection &direction_type, std::function< T(const Context< T > &)> calc, const Event< T > &e) const
Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function, and with an object corresponding to the event that is to be dispatched when this witness function triggers. More...

Protected Member Functions inherited from System< T >
virtual void DoGetWitnessFunctions (const Context< T > &, std::vector< const WitnessFunction< T > *> *) const
Derived classes can override this method to provide witness functions active for the given state. More...

SystemConstraintIndex AddConstraint (std::unique_ptr< SystemConstraint< T >> constraint)
Adds an already-created constraint to the list of constraints for this System. More...

const EventCollection< PublishEvent< T > > & get_forced_publish_events () const

const EventCollection< DiscreteUpdateEvent< T > > & get_forced_discrete_update_events () const

const EventCollection< UnrestrictedUpdateEvent< T > > & get_forced_unrestricted_update_events () const

void set_forced_publish_events (std::unique_ptr< EventCollection< PublishEvent< T >>> forced)

void set_forced_discrete_update_events (std::unique_ptr< EventCollection< DiscreteUpdateEvent< T >>> forced)

void set_forced_unrestricted_update_events (std::unique_ptr< EventCollection< UnrestrictedUpdateEvent< T >>> forced)

System (SystemScalarConverter converter)
Constructs an empty System base class object and allocates base class resources, possibly supporting scalar-type conversion support (AutoDiff, etc.) using converter. More...

const InputPort< T > & DeclareInputPort (variant< std::string, UseDefaultName > name, PortDataType type, int size, optional< RandomDistribution > random_type=nullopt)
Adds a port with the specified type and size to the input topology. More...

const InputPort< T > & DeclareInputPort (PortDataType type, int size, optional< RandomDistribution > random_type=nullopt)
See the nearly identical signature with an additional (first) argument specifying the port name. More...

virtual void DoCalcTimeDerivatives (const Context< T > &context, ContinuousState< T > *derivatives) const
Override this if you have any continuous state variables xc in your concrete System to calculate their time derivatives. More...

virtual T DoCalcPotentialEnergy (const Context< T > &context) const
Override this method for physical systems to calculate the potential energy PE currently stored in the configuration provided in the given Context. More...

virtual T DoCalcKineticEnergy (const Context< T > &context) const
Override this method for physical systems to calculate the kinetic energy KE currently present in the motion provided in the given Context. More...

virtual T DoCalcConservativePower (const Context< T > &context) const
Override this method to return the rate Pc at which mechanical energy is being converted from potential energy to kinetic energy by this system in the given Context. More...

virtual T DoCalcNonConservativePower (const Context< T > &context) const
Override this method to return the rate Pnc at which work W is done on the system by non-conservative forces. More...

virtual void DoMapQDotToVelocity (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &qdot, VectorBase< T > *generalized_velocity) const
Provides the substantive implementation of MapQDotToVelocity(). More...

virtual void DoMapVelocityToQDot (const Context< T > &context, const Eigen::Ref< const VectorX< T >> &generalized_velocity, VectorBase< T > *qdot) const
Provides the substantive implementation of MapVelocityToQDot(). More...

virtual int do_get_num_constraint_equations (const Context< T > &context) const
Gets the number of constraint equations for this system from the given context. More...

virtual Eigen::VectorXd DoEvalConstraintEquations (const Context< T > &context) const
Evaluates the constraint equations for the system at the generalized coordinates and generalized velocity specified by the context. More...

virtual Eigen::VectorXd DoEvalConstraintEquationsDot (const Context< T > &context) const
Computes the time derivative of each constraint equation, evaluated at the generalized coordinates and generalized velocity specified by the context. More...

virtual Eigen::VectorXd DoCalcVelocityChangeFromConstraintImpulses (const Context< T > &context, const Eigen::MatrixXd &J, const Eigen::VectorXd &lambda) const
Computes the change in velocity from applying the given constraint forces to the system at the given context. More...

virtual double DoCalcConstraintErrorNorm (const Context< T > &context, const Eigen::VectorXd &error) const
Computes the norm of the constraint error. More...

Eigen::VectorBlock< VectorX< T > > GetMutableOutputVector (SystemOutput< T > *output, int port_index) const
Returns a mutable Eigen expression for a vector valued output port with index port_index in this system. More...

Protected Member Functions inherited from SystemBase
SystemBase ()=default
(Internal use only) Default constructor. More...

void AddInputPort (std::unique_ptr< InputPortBase > port)
(Internal use only) Adds an already-constructed input port to this System. More...

void AddOutputPort (std::unique_ptr< OutputPortBase > port)
(Internal use only) Adds an already-constructed output port to this System. More...

std::string NextInputPortName (variant< std::string, UseDefaultName > given_name) const
(Internal use only) Returns a name for the next input port, using the given name if it isn't kUseDefaultName, otherwise making up a name like "u3" from the next available input port index. More...

std::string NextOutputPortName (variant< std::string, UseDefaultName > given_name) const
(Internal use only) Returns a name for the next output port, using the given name if it isn't kUseDefaultName, otherwise making up a name like "y3" from the next available output port index. More...

void AddDiscreteStateGroup (DiscreteStateIndex index)
(Internal use only) Assigns a ticket to a new discrete variable group with the given index. More...

void AddAbstractState (AbstractStateIndex index)
(Internal use only) Assigns a ticket to a new abstract state variable with the given index. More...

void AddNumericParameter (NumericParameterIndex index)
(Internal use only) Assigns a ticket to a new numeric parameter with the given index. More...

void AddAbstractParameter (AbstractParameterIndex index)
(Internal use only) Assigns a ticket to a new abstract parameter with the given index. More...

const CacheEntryDeclareCacheEntryWithKnownTicket (DependencyTicket known_ticket, std::string description, CacheEntry::AllocCallback alloc_function, CacheEntry::CalcCallback calc_function, std::set< DependencyTicket > prerequisites_of_calc={ all_sources_ticket()})
(Internal use only) This is for cache entries associated with pre-defined tickets, for example the cache entry for time derivatives. More...

const internal::SystemParentServiceInterface * get_parent_service () const
Returns a pointer to the service interface of the immediately enclosing Diagram if one has been set, otherwise nullptr. More...

DependencyTicket assign_next_dependency_ticket ()
(Internal use only) Assigns the next unused dependency ticket number, unique only within a particular system. More...

const AbstractValueEvalAbstractInputImpl (const char *func, const ContextBase &context, InputPortIndex port_index) const
(Internal use only) Shared code for updating an input port and returning a pointer to its abstract value, or nullptr if the port is not connected. More...

void ThrowNegativePortIndex (const char *func, int port_index) const
Throws std::out_of_range to report a negative port_index that was passed to API method func. More...

void ThrowInputPortIndexOutOfRange (const char *func, InputPortIndex port_index) const
Throws std::out_of_range to report bad input port_index that was passed to API method func. More...

void ThrowOutputPortIndexOutOfRange (const char *func, OutputPortIndex port_index) const
Throws std::out_of_range to report bad output port_index that was passed to API method func. More...

void ThrowNotAVectorInputPort (const char *func, InputPortIndex port_index) const
Throws std::logic_error because someone misused API method func, that is only allowed for declared-vector input ports, on an abstract port whose index is given here. More...

void ThrowInputPortHasWrongType (const char *func, InputPortIndex port_index, const std::string &expected_type, const std::string &actual_type) const
Throws std::logic_error because someone called API method func claiming the input port had some value type that was wrong. More...

void ThrowCantEvaluateInputPort (const char *func, InputPortIndex port_index) const
Throws std::logic_error because someone called API method func, that requires this input port to be evaluatable, but the port was neither fixed nor connected. More...

const InputPortBaseGetInputPortBaseOrThrow (const char *func, int port_index) const
(Internal use only) Returns the InputPortBase at index port_index, throwing std::out_of_range we don't like the port index. More...

const OutputPortBaseGetOutputPortBaseOrThrow (const char *func, int port_index) const
(Internal use only) Returns the OutputPortBase at index port_index, throwing std::out_of_range we don't like the port index. More...

void InitializeContextBase (ContextBase *context) const
This method must be invoked from within derived class DoAllocateContext() implementations right after the concrete Context object has been allocated. More...

## Additional Inherited Members

Static Public Member Functions inherited from System< T >
template<template< typename > class S = ::drake::systems::System>
static std::unique_ptr< S< AutoDiffXd > > ToAutoDiffXd (const S< T > &from)
Creates a deep copy of from, transmogrified to use the autodiff scalar type, with a dynamic-sized vector of partial derivatives. More...

template<template< typename > class S = ::drake::systems::System>
static std::unique_ptr< S< symbolic::Expression > > ToSymbolic (const S< T > &from)
Creates a deep copy of from, transmogrified to use the symbolic scalar type. More...

Static Public Member Functions inherited from SystemBase
static DependencyTicket nothing_ticket ()
Returns a ticket indicating that a computation does not depend on any source value; that is, it is a constant. More...

static DependencyTicket time_ticket ()
Returns a ticket indicating dependence on time. More...

static DependencyTicket accuracy_ticket ()
Returns a ticket indicating dependence on the accuracy setting in the Context. More...

static DependencyTicket q_ticket ()
Returns a ticket indicating that a computation depends on configuration state variables q. More...

static DependencyTicket v_ticket ()
Returns a ticket indicating dependence on velocity state variables v. More...

static DependencyTicket z_ticket ()
Returns a ticket indicating dependence on any or all of the miscellaneous continuous state variables z. More...

static DependencyTicket xc_ticket ()
Returns a ticket indicating dependence on all of the continuous state variables q, v, or z. More...

static DependencyTicket xd_ticket ()
Returns a ticket indicating dependence on all of the numerical discrete state variables, in any discrete variable group. More...

static DependencyTicket xa_ticket ()
Returns a ticket indicating dependence on all of the abstract state variables in the current Context. More...

static DependencyTicket all_state_ticket ()
Returns a ticket indicating dependence on all state variables x in this system, including continuous variables xc, discrete (numeric) variables xd, and abstract state variables xa. More...

static DependencyTicket pn_ticket ()
Returns a ticket indicating dependence on all of the numerical parameters in the current Context. More...

static DependencyTicket pa_ticket ()
Returns a ticket indicating dependence on all of the abstract parameters pa in the current Context. More...

static DependencyTicket all_parameters_ticket ()
Returns a ticket indicating dependence on all parameters p in this system, including numeric parameters pn, and abstract parameters pa. More...

static DependencyTicket all_input_ports_ticket ()
Returns a ticket indicating dependence on all input ports u of this system. More...

static DependencyTicket all_sources_ticket ()
Returns a ticket indicating dependence on every possible independent source value, including time, accuracy, state, input ports, and parameters (but not cache entries). More...

static DependencyTicket configuration_ticket ()
Returns a ticket indicating dependence on all source values that may affect configuration-dependent computations. More...

static DependencyTicket kinematics_ticket ()
Returns a ticket indicating dependence on all source values that may affect configuration- or velocity-dependent computations. More...

static DependencyTicket xcdot_ticket ()
Returns a ticket for the cache entry that holds time derivatives of the continuous variables. More...

static DependencyTicket pe_ticket ()
Returns a ticket for the cache entry that holds the potential energy calculation. More...

static DependencyTicket ke_ticket ()
Returns a ticket for the cache entry that holds the kinetic energy calculation. More...

static DependencyTicket pc_ticket ()
Returns a ticket for the cache entry that holds the conservative power calculation. More...

static DependencyTicket pnc_ticket ()
Returns a ticket for the cache entry that holds the non-conservative power calculation. More...

Static Protected Member Functions inherited from SystemBase
static void set_parent_service (SystemBase *child, const internal::SystemParentServiceInterface *parent_service)
(Internal use only) Declares that parent_service is the service interface of the Diagram that owns this subsystem. More...

static void ThrowInputPortHasWrongType (const char *func, const std::string &system_pathname, InputPortIndex, const std::string &expected_type, const std::string &actual_type)
Throws std::logic_error because someone called API method func claiming the input port had some value type that was wrong. More...

## Detailed Description

### template<typename T> class drake::systems::LeafSystem< T >

A superclass template that extends System with some convenience utilities that are not applicable to Diagrams.

Template Parameters
 T The vector element type, which must be a valid Eigen scalar.

## ◆ LeafSystem() [1/4]

 LeafSystem ( const LeafSystem< T > & )
delete

## ◆ LeafSystem() [2/4]

 LeafSystem ( LeafSystem< T > && )
delete

## ◆ ~LeafSystem()

 ~LeafSystem ( )
inlineoverride

## ◆ LeafSystem() [3/4]

 LeafSystem ( )
inlineprotected

Default constructor that declares no inputs, outputs, state, parameters, events, nor scalar-type conversion support (AutoDiff, etc.).

To enable AutoDiff support, use the SystemScalarConverter-based constructor.

## ◆ LeafSystem() [4/4]

 LeafSystem ( SystemScalarConverter converter )
inlineexplicitprotected

Constructor that declares no inputs, outputs, state, parameters, or events, but allows subclasses to declare scalar-type conversion support (AutoDiff, etc.).

The scalar-type conversion support will use converter. To enable scalar-type conversion support, pass a SystemTypeTag<S>{} where S must be the exact class of this being constructed.

See System Scalar Conversion for detailed background and examples related to scalar-type conversion support.

## ◆ AddTriggeredWitnessFunctionToCompositeEventCollection()

 void AddTriggeredWitnessFunctionToCompositeEventCollection ( Event< T > * event, CompositeEventCollection< T > * events ) const
inlinefinalprotectedvirtual

Add event to events due to a witness function triggering.

events should be allocated with this system's AllocateCompositeEventCollection. Neither event nor events can be nullptr. Additionally, event must contain event data (event->get_event_data() must not be nullptr) and the type of that data must be WitnessTriggeredEventData.

Implements System< T >.

## ◆ AllocateAbstractState()

 virtual std::unique_ptr AllocateAbstractState ( ) const
inlineprotectedvirtual

Reserves the abstract state as required by CreateDefaultContext.

By default, it clones the abstract states declared through DeclareAbstractState() calls. Derived systems may override for different behaviors (not recommended).

Reimplemented in LcmSubscriberSystem, and RobotPlanInterpolator.

## ◆ AllocateCompositeEventCollection()

 std::unique_ptr > AllocateCompositeEventCollection ( ) const
inlinefinalvirtual

Allocates a CompositeEventCollection object for this system.

See also
System::AllocateCompositeEventCollection().

Implements System< T >.

## ◆ AllocateContext()

 std::unique_ptr > AllocateContext ( ) const
inline

Shadows System<T>::AllocateContext to provide a more concrete return type LeafContext<T>.

## ◆ AllocateContinuousState()

 virtual std::unique_ptr > AllocateContinuousState ( ) const
inlineprotectedvirtual

Returns a ContinuousState used to implement both CreateDefaultContext and AllocateTimeDerivatives.

Allocates the state configured with DeclareContinuousState, or none by default. Systems with continuous state variables may override (not recommended), but must ensure the ContinuousState vector is a subclass of BasicVector.

Reimplemented in RigidBodyPlant< T >, and RigidBodyPlant< double >.

## ◆ AllocateDiscreteState()

 virtual std::unique_ptr > AllocateDiscreteState ( ) const
inlineprotectedvirtual

Reserves the discrete state as required by CreateDefaultContext.

By default, clones the model values as provided in DeclareDiscreteState() calls. Alternatively, systems with discrete state can override this method (not recommended).

Reimplemented in RigidBodyPlant< T >, RigidBodyPlant< double >, and LcmSubscriberSystem.

## ◆ AllocateDiscreteVariables()

 std::unique_ptr > AllocateDiscreteVariables ( ) const
inlineoverridevirtual

Returns the AllocateDiscreteState value, which must not be nullptr.

Reimplemented from System< T >.

## ◆ AllocateParameters()

 virtual std::unique_ptr > AllocateParameters ( ) const
inlineprotectedvirtual

Reserves the parameters as required by CreateDefaultContext.

The default implementation in this class clones the model_vector for all parameters declared via DeclareNumericParameter(), as well as the model value for all parameters declared via DeclareAbstractParameter(). Subclasses can override this method if the default behavior is not sufficient.

## ◆ AllocateTimeDerivatives()

 std::unique_ptr > AllocateTimeDerivatives ( ) const
inlineoverridevirtual

Returns the AllocateContinuousState value, which must not be nullptr.

Reimplemented from System< T >.

## ◆ DeclareAbstractInputPort() [1/2]

 const InputPort& DeclareAbstractInputPort ( variant< std::string, UseDefaultName > name, const AbstractValue & model_value )
inlineprotected

Declares an abstract-valued input port using the given model_value.

This is the best way to declare LeafSystem abstract input ports.

Any port connected to this input, and any call to FixInputPort for this input, must provide for values whose type matches this model_value.

See also
System::DeclareInputPort() for more information.

## ◆ DeclareAbstractInputPort() [2/2]

 const InputPort& DeclareAbstractInputPort ( const AbstractValue & model_value )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareAbstractOutputPort() [1/8]

 const OutputPort& DeclareAbstractOutputPort ( variant< std::string, UseDefaultName > name, const OutputType & model_value, void(MySystem::*)(const Context< T > &, OutputType *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

Declares an abstract-valued output port by specifying a model value of concrete type OutputType and a calculator function that is a class member function (method) with signature:

void MySystem::CalcOutputValue(const Context<T>&, OutputType*) const;

where MySystem must be a class derived from LeafSystem<T>. OutputType must be such that Value<OutputType> is permitted. Template arguments will be deduced and do not need to be specified.

See also
drake::systems::Value

## ◆ DeclareAbstractOutputPort() [2/8]

 const OutputPort& DeclareAbstractOutputPort ( variant< std::string, UseDefaultName > name, void(MySystem::*)(const Context< T > &, OutputType *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

Declares an abstract-valued output port by specifying only a calculator function that is a class member function (method) with signature:

void MySystem::CalcOutputValue(const Context<T>&, OutputType*) const;

where MySystem is a class derived from LeafSystem<T>. OutputType is a concrete type such that Value<OutputType> is permitted, and must be default constructible, so that we can create a model value using Value<OutputType>{} (value initialized so numerical types will be zeroed in the model). Template arguments will be deduced and do not need to be specified.

Note
The default constructor will be called once immediately, and subsequent allocations will just copy the model value without invoking the constructor again. If you want the constructor invoked again at each allocation (not common), use one of the other signatures to explicitly provide a method for the allocator to call; that method can then invoke the OutputType default constructor.
See also
drake::systems::Value

## ◆ DeclareAbstractOutputPort() [3/8]

 const OutputPort& DeclareAbstractOutputPort ( variant< std::string, UseDefaultName > name, OutputType(MySystem::*)() const make, void(MySystem::*)(const Context< T > &, OutputType *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

Declares an abstract-valued output port by specifying member functions to use both for the allocator and calculator.

The signatures are:

OutputType MySystem::MakeOutputValue() const;
void MySystem::CalcOutputValue(const Context<T>&, OutputType*) const;

where MySystem is a class derived from LeafSystem<T> and OutputType may be any concrete type such that Value<OutputType> is permitted. See alternate signature if your allocator method needs a Context. Template arguments will be deduced and do not need to be specified.

See also
drake::systems::Value

## ◆ DeclareAbstractOutputPort() [4/8]

 const OutputPort& DeclareAbstractOutputPort ( variant< std::string, UseDefaultName > name, typename LeafOutputPort< T >::AllocCallback alloc_function, typename LeafOutputPort< T >::CalcCallback calc_function, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

(Advanced) Declares an abstract-valued output port using the given allocator and calculator functions provided in their most generic forms.

If you have a member function available use one of the other signatures.

See also
LeafOutputPort::AllocCallback, LeafOutputPort::CalcCallback

## ◆ DeclareAbstractOutputPort() [5/8]

 std::enable_if_t::value, const OutputPort&> DeclareAbstractOutputPort ( const OutputType & model_value, void(MySystem::*)(const Context< T > &, OutputType *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447. Note that the deprecated method is not available for OutputType std::string as that would create an ambiguity. In that case the name is required.

## ◆ DeclareAbstractOutputPort() [6/8]

 const OutputPort& DeclareAbstractOutputPort ( void(MySystem::*)(const Context< T > &, OutputType *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareAbstractOutputPort() [7/8]

 const OutputPort& DeclareAbstractOutputPort ( OutputType(MySystem::*)() const make, void(MySystem::*)(const Context< T > &, OutputType *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareAbstractOutputPort() [8/8]

 const OutputPort& DeclareAbstractOutputPort ( typename LeafOutputPort< T >::AllocCallback alloc_function, typename LeafOutputPort< T >::CalcCallback calc_function, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareAbstractParameter()

 int DeclareAbstractParameter ( const AbstractValue & model_value )
inlineprotected

Declares an abstract parameter using the given model_value.

This is the best way to declare LeafSystem abstract parameters. LeafSystem's default implementation of AllocateParameters uses model_value.Clone(), and the default implementation of SetDefaultParameters() will reset parameters to their model values. Returns the index of the new parameter.

## ◆ DeclareAbstractState()

 AbstractStateIndex DeclareAbstractState ( std::unique_ptr< AbstractValue > abstract_state )
inlineprotected

Declares an abstract state.

Parameters
 abstract_state The abstract state, its ownership is transferred.
Returns
index of the declared abstract state.

## ◆ DeclareContinuousState() [1/4]

 void DeclareContinuousState ( int num_state_variables )
inlineprotected

Declares that this System should reserve continuous state with num_state_variables state variables, which have no second-order structure.

## ◆ DeclareContinuousState() [2/4]

 void DeclareContinuousState ( int num_q, int num_v, int num_z )
inlineprotected

Declares that this System should reserve continuous state with num_q generalized positions, num_v generalized velocities, and num_z miscellaneous state variables.

## ◆ DeclareContinuousState() [3/4]

 void DeclareContinuousState ( const BasicVector< T > & model_vector )
inlineprotected

Declares that this System should reserve continuous state with model_vector.size() miscellaneous state variables, stored in a vector cloned from model_vector.

## ◆ DeclareContinuousState() [4/4]

 void DeclareContinuousState ( const BasicVector< T > & model_vector, int num_q, int num_v, int num_z )
inlineprotected

Declares that this System should reserve continuous state with num_q generalized positions, num_v generalized velocities, and num_z miscellaneous state variables, stored in a vector cloned from model_vector.

Aborts if model_vector has the wrong size. If the model_vector declares any VectorBase::CalcInequalityConstraint() constraints, they will be re-declared as inequality constraints on this system (see DeclareInequalityConstraint()).

## ◆ DeclareDiscreteState() [1/3]

 DiscreteStateIndex DeclareDiscreteState ( const BasicVector< T > & model_vector )
inlineprotected

Declares a discrete state group with model_vector.size() state variables, stored in a vector cloned from model_vector (preserving the concrete type and value).

## ◆ DeclareDiscreteState() [2/3]

 DiscreteStateIndex DeclareDiscreteState ( const Eigen::Ref< const VectorX< T >> & model_vector )
inlineprotected

Declares a discrete state group with model_vector.size() state variables, stored in a BasicVector initialized with the contents of model_vector.

## ◆ DeclareDiscreteState() [3/3]

 DiscreteStateIndex DeclareDiscreteState ( int num_state_variables )
inlineprotected

Declares a discrete state group with num_state_variables state variables, stored in a BasicVector initialized to be all-zero.

If you want non-zero initial values, use an alternate DeclareDiscreteState() signature that accepts a model_vector parameter.

Precondition
num_state_variables must be non-negative.

## ◆ DeclareEqualityConstraint() [1/2]

 SystemConstraintIndex DeclareEqualityConstraint ( void(MySystem::*)(const Context< T > &, VectorX< T > *) const calc, int count, const std::string & description )
inlineprotected

Declares a system constraint of the form f(context) = 0 by specifying a member function to use to calculate the (VectorX) constraint value with a signature:

void MySystem::CalcConstraint(const Context<T>&, VectorX<T>*) const;
Parameters
 count is the dimension of the VectorX output. description should be a human-readable phrase.
Returns
The index of the constraint. Template arguments will be deduced and do not need to be specified.
See also
SystemConstraint<T> for more information about the meaning of these constraints.

## ◆ DeclareEqualityConstraint() [2/2]

 SystemConstraintIndex DeclareEqualityConstraint ( typename SystemConstraint< T >::CalcCallback calc, int count, const std::string & description )
inlineprotected

Declares a system constraint of the form f(context) = 0 by specifying a std::function to use to calculate the (Vector) constraint value with a signature:

void CalcConstraint(const Context<T>&, VectorX<T>*);
Parameters
 count is the dimension of the VectorX output. description should be a human-readable phrase.
Returns
The index of the constraint.
See also
SystemConstraint<T> for more information about the meaning of these constraints.

## ◆ DeclareInequalityConstraint() [1/2]

 SystemConstraintIndex DeclareInequalityConstraint ( void(MySystem::*)(const Context< T > &, VectorX< T > *) const calc, int count, const std::string & description )
inlineprotected

Declares a system constraint of the form f(context) ≥ 0 by specifying a member function to use to calculate the (VectorX) constraint value with a signature:

void MySystem::CalcConstraint(const Context<T>&, VectorX<T>*) const;
Parameters
 count is the dimension of the VectorX output. description should be a human-readable phrase.
Returns
The index of the constraint. Template arguments will be deduced and do not need to be specified.
See also
SystemConstraint<T> for more information about the meaning of these constraints.

## ◆ DeclareInequalityConstraint() [2/2]

 SystemConstraintIndex DeclareInequalityConstraint ( typename SystemConstraint< T >::CalcCallback calc, int count, const std::string & description )
inlineprotected

Declares a system constraint of the form f(context) ≥ 0 by specifying a std::function to use to calculate the (Vector) constraint value with a signature:

void CalcConstraint(const Context<T>&, VectorX<T>*);
Parameters
 count is the dimension of the VectorX output. description should be a human-readable phrase.
Returns
The index of the constraint.
See also
SystemConstraint<T> for more information about the meaning of these constraints.

## ◆ DeclareInitializationEvent()

 void DeclareInitializationEvent ( const EventType & event )
inlineprotected

Declares an initialization event by deep copying event and storing it internally.

event's associated trigger type must be unknown or already set to Event::TriggerType::kInitialization. Aborts otherwise.

## ◆ DeclareNumericParameter()

 int DeclareNumericParameter ( const BasicVector< T > & model_vector )
inlineprotected

Declares a numeric parameter using the given model_vector.

This is the best way to declare LeafSystem numeric parameters. LeafSystem's default implementation of AllocateParameters uses model_vector.Clone(), and the default implementation of SetDefaultParameters() will reset parameters to their model vectors. If the model_vector declares any VectorBase::CalcInequalityConstraint() constraints, they will be re-declared as inequality constraints on this system (see DeclareInequalityConstraint()). Returns the index of the new parameter.

## ◆ DeclarePeriodicDiscreteUpdate()

 void DeclarePeriodicDiscreteUpdate ( double period_sec, double offset_sec = 0 )
inlineprotected

Declares a periodic discrete update event with period = period_sec and offset = offset_sec.

The event does not have a custom callback function, and its trigger will be set to Event::TriggerType::kPeriodic. Its attribute will be an Event<T>::PeriodicAttribute of offset_sec and period_sec. Authors are encouraged to read Discrete Systems for implications of mixing discrete and continuous systems.

## ◆ DeclarePeriodicEvent() [1/2]

 void DeclarePeriodicEvent ( double period_sec, double offset_sec )
inlineprotected

Declares that this System has a simple, fixed-period event specified with no custom callback function, and its attribute field contains an Event<T>::PeriodicAttribute constructed from the specified period_sec and offset_sec.

The first tick will occur at t = offset_sec, and it will recur at every period_sec thereafter. Note that the periodic events returned by system::CalcNextUpdateTime() will happen at a time strictly after the querying time. E.g. if there is a periodic event with offset = 0 and period = 5, when calling CalcNextUpdateTime() at t = 0, the returned event will happen at t = 5 not t = 0.

Template Parameters
 EventType A class derived from Event (e.g., PublishEvent, DiscreteUpdateEvent, UnrestrictedUpdateEvent, etc.)

## ◆ DeclarePeriodicEvent() [2/2]

 void DeclarePeriodicEvent ( double period_sec, double offset_sec, const EventType & event )
inlineprotected

Declares that this System has a simple, fixed-period event specified by event.

The first tick will occur at t = offset_sec, and it will recur at every period_sec thereafter. Note that the periodic events returned by system::CalcNextUpdateTime() will happen at a time strictly after the querying time. E.g. if there is a periodic event with offset = 0 and period = 5, when calling CalcNextUpdateTime() at t = 0, the returned event will happen at t = 5 not t = 0.

A deep copy of event will be made and maintained by this. The trigger type in the clone will be set to kPeriodic, unless it is already set in the source event in which case it must be kPeriodic already. The event's attribute field is preserved.

Template Parameters
 EventType A class derived from Event (e.g., PublishEvent, DiscreteUpdateEvent, UnrestrictedUpdateEvent, etc.)

## ◆ DeclarePeriodicPublish()

 void DeclarePeriodicPublish ( double period_sec, double offset_sec = 0 )
inlineprotected

Declares a periodic publish event with period = period_sec and offset = offset_sec.

The event does not have a custom callback function, and its trigger will be set to Event::TriggerType::kPeriodic. Its attribute will be an Event<T>::PeriodicAttribute of offset_sec and period_sec.

## ◆ DeclarePeriodicUnrestrictedUpdate()

 void DeclarePeriodicUnrestrictedUpdate ( double period_sec, double offset_sec = 0 )
inlineprotected

Declares a periodic unrestricted update event with period = period_sec and offset = offset_sec.

The event does not have a custom callback function, and its trigger will be set to Event::TriggerType::kPeriodic. Its attribute will be an Event<T>::PeriodicAttribute of offset_sec and period_sec.

## ◆ DeclarePerStepEvent()

 void DeclarePerStepEvent ( const EventType & event )
inlineprotected

Declares a per-step event using event, which is deep copied (the copy is maintained by this).

event's associated trigger type must be unknown or already set to Event::TriggerType::kPerStep. Aborts otherwise.

## ◆ DeclareVectorInputPort() [1/2]

 const InputPort& DeclareVectorInputPort ( variant< std::string, UseDefaultName > name, const BasicVector< T > & model_vector, optional< RandomDistribution > random_type = nullopt )
inlineprotected

Declares a vector-valued input port using the given model_vector.

This is the best way to declare LeafSystem input ports that require subclasses of BasicVector. The port's size and type will be the same as model_vector. If the port is intended to model a random noise or disturbance input, random_type can (optionally) be used to label it as such. If the model_vector declares any VectorBase::CalcInequalityConstraint() constraints, they will be re-declared as inequality constraints on this system (see DeclareInequalityConstraint()).

See also
System::DeclareInputPort() for more information.

## ◆ DeclareVectorInputPort() [2/2]

 const InputPort& DeclareVectorInputPort ( const BasicVector< T > & model_vector, optional< RandomDistribution > random_type = nullopt )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareVectorOutputPort() [1/6]

 const OutputPort& DeclareVectorOutputPort ( variant< std::string, UseDefaultName > name, const BasicVectorSubtype & model_vector, void(MySystem::*)(const Context< T > &, BasicVectorSubtype *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

Declares a vector-valued output port by specifying (1) a model vector of type BasicVectorSubtype derived from BasicVector and initialized to the correct size and desired initial value, and (2) a calculator function that is a class member function (method) with signature:

void MySystem::CalcOutputVector(const Context<T>&,
BasicVectorSubtype*) const;

where MySystem is a class derived from LeafSystem<T>. Template arguments will be deduced and do not need to be specified.

## ◆ DeclareVectorOutputPort() [2/6]

 const OutputPort& DeclareVectorOutputPort ( variant< std::string, UseDefaultName > name, void(MySystem::*)(const Context< T > &, BasicVectorSubtype *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

Declares a vector-valued output port by specifying only a calculator function that is a class member function (method) with signature:

void MySystem::CalcOutputVector(const Context<T>&,
BasicVectorSubtype*) const;

where MySystem is a class derived from LeafSystem<T> and BasicVectorSubtype is derived from BasicVector<T> and has a suitable default constructor that allocates a vector of the expected size. This will use BasicVectorSubtype{} (that is, the default constructor) to produce a model vector for the output port's value. Template arguments will be deduced and do not need to be specified.

Note
The default constructor will be called once immediately, and subsequent allocations will just copy the model value without invoking the constructor again. If you want the constructor invoked again at each allocation (not common), use one of the other signatures to explicitly provide a method for the allocator to call; that method can then invoke the BasicVectorSubtype default constructor.

## ◆ DeclareVectorOutputPort() [3/6]

 const OutputPort& DeclareVectorOutputPort ( variant< std::string, UseDefaultName > name, const BasicVector< T > & model_vector, typename LeafOutputPort< T >::CalcVectorCallback vector_calc_function, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

(Advanced) Declares a vector-valued output port using the given model_vector and a function for calculating the port's value at runtime.

The port's size will be model_vector.size(), and the default allocator for the port will be model_vector.Clone(). Note that this takes the calculator function in its most generic form; if you have a member function available use one of the other signatures.

See also
LeafOutputPort::CalcVectorCallback

## ◆ DeclareVectorOutputPort() [4/6]

 const OutputPort& DeclareVectorOutputPort ( const BasicVectorSubtype & model_vector, void(MySystem::*)(const Context< T > &, BasicVectorSubtype *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareVectorOutputPort() [5/6]

 const OutputPort& DeclareVectorOutputPort ( void(MySystem::*)(const Context< T > &, BasicVectorSubtype *) const calc, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareVectorOutputPort() [6/6]

 const OutputPort& DeclareVectorOutputPort ( const BasicVector< T > & model_vector, typename LeafOutputPort< T >::CalcVectorCallback vector_calc_function, std::set< DependencyTicket > prerequisites_of_calc = { all_sources_ticket()} )
inlineprotected

See the nearly identical signature with an additional (first) argument specifying the port name.

This version will be deprecated as discussed in #9447.

## ◆ DeclareWitnessFunction() [1/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, T(MySystem::*)(const Context< T > &) const calc ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function; and with no event object.

Note
Constructing a witness function with no corresponding event forces Simulator's integration of an ODE to end a step at the witness isolation time. For example, isolating a function's minimum or maximum values can be realized with a witness that triggers on a sign change of the function's time derivative, ensuring that the actual extreme value is present in the discretized trajectory.

## ◆ DeclareWitnessFunction() [2/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, std::function< T(const Context< T > &)> calc ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function; and with no event object.

## ◆ DeclareWitnessFunction() [3/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, T(MySystem::*)(const Context< T > &) const calc, void(MySystem::*)(const Context< T > &, const PublishEvent< T > &) const publish_callback ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and publish event callback function for when this triggers.

## ◆ DeclareWitnessFunction() [4/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, T(MySystem::*)(const Context< T > &) const calc, void(MySystem::*)(const Context< T > &, const DiscreteUpdateEvent< T > &, DiscreteValues< T > *) const du_callback ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and discrete update event callback function for when this triggers.

## ◆ DeclareWitnessFunction() [5/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, T(MySystem::*)(const Context< T > &) const calc, void(MySystem::*)(const Context< T > &, const UnrestrictedUpdateEvent< T > &, State< T > *) const uu_callback ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, calculator function, and unrestricted update event callback function for when this triggers.

## ◆ DeclareWitnessFunction() [6/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, T(MySystem::*)(const Context< T > &) const calc, const Event< T > & e ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function, and with an object corresponding to the event that is to be dispatched when this witness function triggers.

Example types of event objects are publish, discrete variable update, unrestricted update events. A clone of the event will be owned by the newly constructed WitnessFunction.

## ◆ DeclareWitnessFunction() [7/7]

 std::unique_ptr > DeclareWitnessFunction ( const std::string & description, const WitnessFunctionDirection & direction_type, std::function< T(const Context< T > &)> calc, const Event< T > & e ) const
inlineprotected

Constructs the witness function with the given description (used primarily for debugging and logging), direction type, and calculator function, and with an object corresponding to the event that is to be dispatched when this witness function triggers.

Example types of event objects are publish, discrete variable update, unrestricted update events. A clone of the event will be owned by the newly constructed WitnessFunction.

## ◆ DoAllocateContext()

 std::unique_ptr DoAllocateContext ( ) const
inlinefinalvirtual

Derived class implementations should allocate a suitable concrete Context type, then invoke the above InitializeContextBase() method.

A Diagram must then invoke AllocateContext() to obtain each of the subcontexts for its DiagramContext, and must set up inter-subcontext dependencies among its children and between itself and its children. Then context resources such as parameters and state should be allocated.

Implements SystemBase.

## ◆ DoCalcDiscreteVariableUpdates()

 virtual void DoCalcDiscreteVariableUpdates ( const Context< T > & context, const std::vector< const DiscreteUpdateEvent< T > *> & events, DiscreteValues< T > * discrete_state ) const
inlineprotectedvirtual

Derived-class event handler for all simultaneous discrete update events.

This method updates the discrete_state on discrete update events. The default implementation traverses events in the arbitrary order they appear in events, and for each event that has a callback function, it will invoke it with context, that event, and discrete_state. Note that the same discrete_state is passed to subsequent callbacks. Override this in your derived LeafSystem if your derived LeafSystem requires a behavior other than the default.

This method is called only from the virtual DispatchDiscreteVariableUpdateHandler(), which is only called from the public non-virtual CalcDiscreteVariableUpdates(), which will already have error-checked the parameters so you don't have to. In particular, implementations may assume that context is valid; that discrete_state is non-null, and that the referenced object has the same constituent structure as was produced by AllocateDiscreteVariables().

Parameters
 [in] context The "before" state. [in] events All the discrete update events that need handling. [in,out] discrete_state The current state of the system on input; the desired state of the system on return.

## ◆ DoCalcNextUpdateTime()

 void DoCalcNextUpdateTime ( const Context< T > & context, CompositeEventCollection< T > * events, T * time ) const
inlineoverrideprotectedvirtual

Computes the next update time based on the configured periodic events, for scalar types that are arithmetic, or aborts for scalar types that are not arithmetic.

Subclasses that require aperiodic events should override.

Postcondition
time is set to a value greater than or equal to context.get_time() on return.
Warning
If you override this method, think carefully before setting time to context.get_time() on return, which can inadvertently cause simulations of systems derived from LeafSystem to loop interminably. Such a loop will occur if, for example, the event(s) does not modify the state.

Reimplemented from System< T >.

## ◆ DoCalcUnrestrictedUpdate()

 virtual void DoCalcUnrestrictedUpdate ( const Context< T > & context, const std::vector< const UnrestrictedUpdateEvent< T > *> & events, State< T > * state ) const
inlineprotectedvirtual

Derived-class event handler for all simultaneous unrestricted update events.

This function updates the state in an unrestricted fashion on unrestricted update events. Override this function if you need your System to update abstract variables or generally make changes to state that cannot be made using CalcDiscreteVariableUpdates() or via integration of continuous variables.

The default implementation traverses events in the arbitrary order they appear in events, and for each event that has a callback function, it will invoke it with context, that event, and state. Note that the same state is passed to subsequent callbacks. Override this if your derived LeafSystem requires a behavior other than the default.

This method is called only from the virtual DispatchUnrestrictedUpdateHandler(), which is only called from the non-virtual public CalcUnrestrictedUpdate(), which will already have error-checked the parameters so you don't have to. In particular, implementations may assume that the context is valid; that state is non-null, and that the referenced object has the same constituent structure as the state in context.

Parameters
 [in] context The "before" state that is to be used to calculate the returned state update. [in] events All the unrestricted update events that need handling. [in,out] state The current state of the system on input; the desired state of the system on return.

Reimplemented in LcmSubscriberSystem, ZeroOrderHold< T >, RobotPlanInterpolator, PlanEvalBaseSystem, and QpInverseDynamicsSystem.

## ◆ DoCalcWitnessValue()

 T DoCalcWitnessValue ( const Context< T > & context, const WitnessFunction< T > & witness_func ) const
inlinefinalprotectedvirtual

Derived classes will implement this method to evaluate a witness function at the given context.

Implements System< T >.

## ◆ DoHasDirectFeedthrough()

 virtual optional DoHasDirectFeedthrough ( int input_port, int output_port ) const
inlineprotectedvirtual

Returns true if there is direct-feedthrough from the given input_port to the given output_port, false if there is not direct-feedthrough, or nullopt if unknown (in which case SystemSymbolicInspector will attempt to measure the feedthrough using symbolic form).

By default, LeafSystem assumes there is direct feedthrough of values from every input to every output. This is a conservative assumption that ensures we detect and can prevent the formation of algebraic loops (implicit computations) in system Diagrams. Systems which do not have direct feedthrough may override that assumption in two ways:

• Override DoToSymbolic, allowing LeafSystem to infer the sparsity from the symbolic equations. This method is typically preferred for systems that have a symbolic form, but should be avoided in certain corner cases where fully descriptive symbolic analysis is impossible, e.g., when the symbolic form depends on C++ native conditionals. For additional discussion, consult the documentation for SystemSymbolicInspector.
• Override this function directly, reporting manual sparsity. This method is recommended when DoToSymbolic has not been implemented, or when creating the symbolic form is too computationally expensive, or when its output is not fully descriptive, as discussed above. Manually configured sparsity must be conservative: if there is any Context for which an input port is direct-feedthrough to an output port, this function must return either true or nullopt for those two ports.

## ◆ DoMakeLeafContext()

 virtual std::unique_ptr > DoMakeLeafContext ( ) const
inlineprotectedvirtual

Provides a new instance of the leaf context for this system.

Derived leaf systems with custom derived leaf system contexts should override this to provide a context of the appropriate type. The returned context should be "empty"; invoked by AllocateContext(), the caller will take the responsibility to initialize the core LeafContext data. The default implementation provides a default-constructed LeafContext<T>.

## ◆ DoPublish()

 virtual void DoPublish ( const Context< T > & context, const std::vector< const PublishEvent< T > *> & events ) const
inlineprotectedvirtual

Derived-class event handler for all simultaneous publish events in events.

Override this in your derived LeafSystem if your derived LeafSystem requires a behavior other than the default behavior, which traverses events in the arbitrary order they appear in events, and for each event that has a callback function, it will invoke the callback with context and that event. This can be used for tasks that need read-only access to the context, such as sending messages, producing console output, debugging, logging, saving the trajectory to a file, etc.

This method is called only from the virtual DispatchPublishHandler, which is only called from the public non-virtual Publish(), which will have already error-checked context so you may assume that it is valid.

Parameters
 [in] context Const current context. [in] events All the publish events that need handling.

Reimplemented in StatelessSystem< T >.

## ◆ DoValidateAllocatedLeafContext()

 virtual void DoValidateAllocatedLeafContext ( const LeafContext< T > & context ) const
inlineprotectedvirtual

Derived classes that impose restrictions on what resources are permitted should check those restrictions by implementing this.

For example, a derived class might require a single input and single output. Note that the supplied Context will be complete except that input and output dependencies on peer and parent subcontexts will not yet have been set up, so you may not consider them for validation. The default implementation does nothing.

## ◆ get_num_continuous_states()

 int get_num_continuous_states ( ) const
inlinefinalvirtual

Returns the dimension of the continuous state vector that has been declared until now.

Implements System< T >.

## ◆ GetDirectFeedthroughs()

 std::multimap GetDirectFeedthroughs ( ) const
inlinefinalvirtual

Reports all direct feedthroughs from input ports to output ports.

For a system with m input ports: I = i₀, i₁, ..., iₘ₋₁, and n output ports, O = o₀, o₁, ..., oₙ₋₁, the return map will contain pairs (u, v) such that

• 0 ≤ u < m,
• 0 ≤ v < n,
• and there might be a direct feedthrough from input iᵤ to each output oᵥ.

Implements System< T >.

## ◆ GetGraphvizFragment()

 void GetGraphvizFragment ( int max_depth, std::stringstream * dot ) const
inlineoverrideprotectedvirtual

Emits a graphviz fragment for this System.

Leaf systems are visualized as records. For instance, a leaf system with 2 inputs and 1 output is:

/// 123456 [shape= record, label="name | {<u0> 0 |<y0> 0} | {<u1> 1 | }"];
/// 
which looks like:

/// +------------+----+
/// | name  | u0 | u1 |
/// |       | y0 |    |
/// +-------+----+----+
/// 

Reimplemented from System< T >.

## ◆ GetGraphvizInputPortToken()

 void GetGraphvizInputPortToken ( const InputPort< T > & port, int max_depth, std::stringstream * dot ) const
inlinefinalprotectedvirtual

Appends a fragment to the dot stream identifying the graphviz node representing port.

Does nothing by default.

Reimplemented from System< T >.

## ◆ GetGraphvizOutputPortToken()

 void GetGraphvizOutputPortToken ( const OutputPort< T > & port, int max_depth, std::stringstream * dot ) const
inlinefinalprotectedvirtual

Appends a fragment to the dot stream identifying the graphviz node representing port.

Does nothing by default.

Reimplemented from System< T >.

## ◆ GetMutableNumericParameter()

 U& GetMutableNumericParameter ( Context< T > * context, int index ) const
inlineprotected

Extracts the numeric parameters of type U from the context at index.

Asserts if the context is not a LeafContext, or if it does not have a vector-valued parameter of type U at index.

## ◆ GetNumericParameter()

 const U& GetNumericParameter ( const Context< T > & context, int index ) const
inlineprotected

Extracts the numeric parameters of type U from the context at index.

Asserts if the context is not a LeafContext, or if it does not have a vector-valued parameter of type U at index.

## ◆ operator=() [1/2]

 LeafSystem& operator= ( const LeafSystem< T > & )
delete

## ◆ operator=() [2/2]

 LeafSystem& operator= ( LeafSystem< T > && )
delete

## ◆ SetDefaultParameters()

 void SetDefaultParameters ( const Context< T > & context, Parameters< T > * parameters ) const
inlineoverridevirtual

Default implementation: sets all numeric parameters to the model vector given to DeclareNumericParameter, or else if no model was provided sets the numeric parameter to one.

It sets all abstract parameters to the model value given to DeclareAbstractParameter. Overrides must not change the number of parameters.

Implements System< T >.

## ◆ SetDefaultState()

 void SetDefaultState ( const Context< T > & context, State< T > * state ) const
inlineoverridevirtual

Default implementation: sets all continuous state to the model vector given in DeclareContinuousState (or zero if no model vector was given) and discrete states to zero.

Overrides must not change the number of state variables.

Implements System< T >.

The documentation for this class was generated from the following file: