Class ExpandableStatefulODE

java.lang.Object
org.apache.commons.math3.ode.ExpandableStatefulODE
public class ExpandableStatefulODE extends Object
This class represents a combined set of first order differential equations, with at least a primary set of equations expandable by some sets of secondary equations.

One typical use case is the computation of the Jacobian matrix for some ODE. In this case, the primary set of equations corresponds to the raw ODE, and we add to this set another bunch of secondary equations which represent the Jacobian matrix of the primary set.

We want the integrator to use only the primary set to estimate the errors and hence the step sizes. It should not use the secondary equations in this computation. The integrator will be able to know where the primary set ends and so where the secondary sets begin.

Since:
3.0
See Also:

  • Field Details

    • primary

      private final FirstOrderDifferentialEquations primary
      Primary differential equation.

    • primaryMapper

      private final EquationsMapper primaryMapper
      Mapper for primary equation.

    • time

      private double time
      Time.

    • primaryState

      private final double[] primaryState
      State.

    • primaryStateDot

      private final double[] primaryStateDot
      State derivative.

    • components

      private List<ExpandableStatefulODE.SecondaryComponent> components
      Components of the expandable ODE.

  • Constructor Details

    • ExpandableStatefulODE

      public ExpandableStatefulODE(FirstOrderDifferentialEquations primary)
      Build an expandable set from its primary ODE set.
      Parameters:
      primary - the primary set of differential equations to be integrated.

  • Method Details

    • getPrimary

      public FirstOrderDifferentialEquations getPrimary()
      Get the primary set of differential equations.
      Returns:
      primary set of differential equations

    • getTotalDimension

      public int getTotalDimension()
      Return the dimension of the complete set of equations.

      The complete set of equations correspond to the primary set plus all secondary sets.

      Returns:
      dimension of the complete set of equations

    • computeDerivatives

      public void computeDerivatives(double t, double[] y, double[] yDot) throws MaxCountExceededException, DimensionMismatchException
      Get the current time derivative of the complete state vector.
      Parameters:
      t - current value of the independent time variable
      y - array containing the current value of the complete state vector
      yDot - placeholder array where to put the time derivative of the complete state vector
      Throws:
      MaxCountExceededException - if the number of functions evaluations is exceeded
      DimensionMismatchException - if arrays dimensions do not match equations settings

    • addSecondaryEquations

      public int addSecondaryEquations(SecondaryEquations secondary)
      Add a set of secondary equations to be integrated along with the primary set.
      Parameters:
      secondary - secondary equations set
      Returns:
      index of the secondary equation in the expanded state

    • getPrimaryMapper

      public EquationsMapper getPrimaryMapper()
      Get an equations mapper for the primary equations set.
      Returns:
      mapper for the primary set
      See Also:

    • getSecondaryMappers

      public EquationsMapper[] getSecondaryMappers()
      Get the equations mappers for the secondary equations sets.
      Returns:
      equations mappers for the secondary equations sets
      See Also:

    • setTime

      public void setTime(double time)
      Set current time.
      Parameters:
      time - current time

    • getTime

      public double getTime()
      Get current time.
      Returns:
      current time

    • setPrimaryState

      public void setPrimaryState(double[] primaryState) throws DimensionMismatchException
      Set primary part of the current state.
      Parameters:
      primaryState - primary part of the current state
      Throws:
      DimensionMismatchException - if the dimension of the array does not match the primary set

    • getPrimaryState

      public double[] getPrimaryState()
      Get primary part of the current state.
      Returns:
      primary part of the current state

    • getPrimaryStateDot

      public double[] getPrimaryStateDot()
      Get primary part of the current state derivative.
      Returns:
      primary part of the current state derivative

    • setSecondaryState

      public void setSecondaryState(int index, double[] secondaryState) throws DimensionMismatchException
      Set secondary part of the current state.
      Parameters:
      index - index of the part to set as returned by addSecondaryEquations(SecondaryEquations)
      secondaryState - secondary part of the current state
      Throws:
      DimensionMismatchException - if the dimension of the partial state does not match the selected equations set dimension

    • getSecondaryState

      public double[] getSecondaryState(int index)
      Get secondary part of the current state.
      Parameters:
      index - index of the part to set as returned by addSecondaryEquations(SecondaryEquations)
      Returns:
      secondary part of the current state

    • getSecondaryStateDot

      public double[] getSecondaryStateDot(int index)
      Get secondary part of the current state derivative.
      Parameters:
      index - index of the part to set as returned by addSecondaryEquations(SecondaryEquations)
      Returns:
      secondary part of the current state derivative

    • setCompleteState

      public void setCompleteState(double[] completeState) throws DimensionMismatchException
      Set the complete current state.
      Parameters:
      completeState - complete current state to copy data from
      Throws:
      DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension

    • getCompleteState

      public double[] getCompleteState() throws DimensionMismatchException
      Get the complete current state.
      Returns:
      complete current state
      Throws:
      DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension