StateVariable Class
(CDPSim::StateVariable)The StateVariable wraps a state and its derivative. It is used by classes inheriting from DynamicSimComponent. More...
| Header: | #include <StateVariable> |
| Inherits: | CDP::StudioAPI::CDPNode |
Public Functions
| StateVariable() | |
| virtual | ~StateVariable() override |
| virtual void | Configure(XMLElementEx *pStateVariableXML) |
| virtual void | Create(const std::string &name, DynamicSimComponent *componentOwner, ICDPNode *nodeOwner = nullptr) |
| virtual double * | GetValuePointer() const |
| void | OverrideStateValue(double newValue) |
| virtual void | UpdateValueFromConfiguration() |
| operator double() const |
Reimplemented Public Functions
| virtual void | FillNodeChildren(CDP::StudioAPI::NodeStream &serializer) const override |
| virtual const std::string | GetNodeName() const override |
| virtual std::string | GetNodeTypeName() const override |
| virtual CDP::StudioAPI::CDPValueType | GetNodeValueType() const override |
| virtual CDP::StudioAPI::CDPVariantValue | GetVariantValue() const override |
- 27 public functions inherited from CDP::StudioAPI::CDPNode
- 22 public functions inherited from CDP::StudioAPI::ICDPNode
Additional Inherited Members
- 1 protected function inherited from CDP::StudioAPI::CDPNode
Detailed Description
The StateVariable wraps a state and its derivative. It is used by classes inheriting from DynamicSimComponent.
Usage
Instantiate as a member of a parent DynamicSimComponent in the header file and call Create() during initialization.
To read "the state", use the object as if it is a double (e.g. "Output = x;"). To write "the state", use the OverrideStateValue() function (e.g. "x.OverrideStateValue(0);"). To read or write "the state's derivative" (usually done in simulator component DynamicSimComponent::EvaluateDiffEquations() method), read or write the .ddt member (e.g. "x.ddt = v;").
Example
In the class declaration:
CDPSim::StateVariable x, v;
In the implementation file: In Create(...):
x.Create("x", this); v.Create("v", this);
In EvaluateDiffEquations(...):
x.ddt = v; // Set "x's derivative" to "v's state". v.ddt = F/m;
Alternatively, when the DynamicSimComponent's SolverType="1 - Algebraic (DAE)", instead set the residuals in EvaluateAlgebraicEquations(...)
x.residual = x.ddt - v; v.residual = v.ddt - F/m;
In PostIntegrate(...):
if (x < 0) // Simulate a wall at x==0 { x.OverrideStateValue(0); v.OverrideStateValue(0); // Reset speed to 0 after hitting a wall x.ddt = 0; }
Member Function Documentation
StateVariable::StateVariable()
Default constructs an instance of StateVariable.
[override virtual] StateVariable::~StateVariable()
Destroys the instance of StateVariable. The destructor is virtual.
[virtual] void StateVariable::Configure(XMLElementEx *pStateVariableXML)
Reads configuration from XML. Called automatically by parent DynamicSimComponent.
[virtual] void StateVariable::Create(const std::string &name, DynamicSimComponent *componentOwner, ICDPNode *nodeOwner = nullptr)
Creates the instance, binds it to name and registers to componentOwner.
[override virtual] void StateVariable::FillNodeChildren(CDP::StudioAPI::NodeStream &serializer) const
Reimplemented from CDPNode::FillNodeChildren().
Exposes child nodes of this node to StudioAPI.
[override virtual] const std::string StateVariable::GetNodeName() const
Reimplemented from ICDPNode::GetNodeName().
Returns node's unique name.
[override virtual] std::string StateVariable::GetNodeTypeName() const
Reimplemented from ICDPNode::GetNodeTypeName().
Returns node's model name.
[override virtual] CDP::StudioAPI::CDPValueType StateVariable::GetNodeValueType() const
Reimplemented from ICDPNode::GetNodeValueType().
Returns node's value type which is double.
[virtual] double *StateVariable::GetValuePointer() const
Returns pointer to the node's internal value.
[override virtual] CDP::StudioAPI::CDPVariantValue StateVariable::GetVariantValue() const
Reimplemented from ICDPNode::GetVariantValue().
Returns node's value.
void StateVariable::OverrideStateValue(double newValue)
Use this method to override the state variable's value to something else than what the simulator calculates. This can be done in DynamicSimComponent::Reset(), DynamicSimComponent::PreIntegrate(), DynamicSimComponent::PostIntegrate() and DynamicSimComponent::SetProperty() (when called by CDPBaseObject::MessageSetProperty()).
This method should not be called from DynamicSimComponent::EvaluateDiffEquations() or DynamicSimComponent::EvaluateAlgebraicEquations().
[virtual] void StateVariable::UpdateValueFromConfiguration()
Resets value to initial value read from configuration.
StateVariable::operator double() const
Returns the state variable's value.
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