Examples of ExpandableStatefulODE

org.apache.commons.math3.ode.ExpandableStatefulODE
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 {@link AbstractIntegrator integrator} willbe able to know where the primary set ends and so where the secondary sets begin.
@see FirstOrderDifferentialEquations @see JacobianMatrices @since 3.0

Examples of org.apache.commons.math3.ode.ExpandableStatefulODE


            // predict a first estimate of the state at step end
            final double stepEnd = stepStart + stepSize;
            interpolator.shift();
            interpolator.setInterpolatedTime(stepEnd);
            final ExpandableStatefulODE expandable = getExpandable();
            final EquationsMapper primary = expandable.getPrimaryMapper();
            primary.insertEquationData(interpolator.getInterpolatedState(), y);
            int index = 0;
            for (final EquationsMapper secondary : expandable.getSecondaryMappers()) {
                secondary.insertEquationData(interpolator.getInterpolatedSecondaryState(index), y);
                ++index;
            }


            // evaluate the derivative

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Examples of org.apache.commons.math3.ode.ExpandableStatefulODE

                stepSize = hNew;


                // predict a first estimate of the state at step end (P in the PECE sequence)
                final double stepEnd = stepStart + stepSize;
                interpolator.setInterpolatedTime(stepEnd);
                final ExpandableStatefulODE expandable = getExpandable();
                final EquationsMapper primary = expandable.getPrimaryMapper();
                primary.insertEquationData(interpolator.getInterpolatedState(), yTmp);
                int index = 0;
                for (final EquationsMapper secondary : expandable.getSecondaryMappers()) {
                    secondary.insertEquationData(interpolator.getInterpolatedSecondaryState(index), yTmp);
                    ++index;
                }


                // evaluate a first estimate of the derivative (first E in the PECE sequence)

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Examples of org.apache.commons.math3.ode.ExpandableStatefulODE


        final double tolerance = 0.1;
        EventState es = new EventState(closeEventsGenerator, 1.5 * gap,
                                       tolerance, 100,
                                       new BrentSolver(tolerance));
        es.setExpandable(new ExpandableStatefulODE(new FirstOrderDifferentialEquations() {
            public int getDimension() {
                return 0;
            }
            public void computeDerivatives(double t, double[] y, double[] yDot) {
            }

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Examples of org.apache.commons.math3.ode.ExpandableStatefulODE

    @Test
    public void testIssue965()
        throws DimensionMismatchException, NumberIsTooSmallException,
               MaxCountExceededException, NoBracketingException {


        ExpandableStatefulODE equation =
                new ExpandableStatefulODE(new FirstOrderDifferentialEquations() {
            
            public int getDimension() {
                return 1;
            }
            
            public void computeDerivatives(double t, double[] y, double[] yDot) {
                yDot[0] = 2.0;
            }
        });
        equation.setTime(0.0);
        equation.setPrimaryState(new double[1]);
        equation.addSecondaryEquations(new SecondaryEquations() {
            
            public int getDimension() {
                return 1;
            }
            
            public void computeDerivatives(double t, double[] primary,
                                           double[] primaryDot, double[] secondary,
                                           double[] secondaryDot) {
                secondaryDot[0] = -3.0;
            }
        });
        int index = equation.getSecondaryMappers()[0].getFirstIndex();


        DormandPrince853Integrator integrator = new DormandPrince853Integrator(0.001, 1000, 1.0e-14, 1.0e-14);
        integrator.addEventHandler(new SecondaryStateEvent(index, -3.0), 0.1, 1.0e-9, 1000);
        integrator.setInitialStepSize(3.0);


        integrator.integrate(equation, 30.0);
        Assert.assertEquals( 1.0, equation.getTime(), 1.0e-10);
        Assert.assertEquals( 2.0, equation.getPrimaryState()[0], 1.0e-10);
        Assert.assertEquals(-3.0, equation.getSecondaryState(0)[0], 1.0e-10);


    }

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Examples of org.apache.commons.math3.ode.ExpandableStatefulODE

                stepSize = hNew;


                // predict a first estimate of the state at step end (P in the PECE sequence)
                final double stepEnd = stepStart + stepSize;
                interpolator.setInterpolatedTime(stepEnd);
                final ExpandableStatefulODE expandable = getExpandable();
                final EquationsMapper primary = expandable.getPrimaryMapper();
                primary.insertEquationData(interpolator.getInterpolatedState(), yTmp);
                int index = 0;
                for (final EquationsMapper secondary : expandable.getSecondaryMappers()) {
                    secondary.insertEquationData(interpolator.getInterpolatedSecondaryState(index), yTmp);
                    ++index;
                }


                // evaluate a first estimate of the derivative (first E in the PECE sequence)

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Examples of org.apache.commons.math3.ode.ExpandableStatefulODE


            // predict a first estimate of the state at step end
            final double stepEnd = stepStart + stepSize;
            interpolator.shift();
            interpolator.setInterpolatedTime(stepEnd);
            final ExpandableStatefulODE expandable = getExpandable();
            final EquationsMapper primary = expandable.getPrimaryMapper();
            primary.insertEquationData(interpolator.getInterpolatedState(), y);
            int index = 0;
            for (final EquationsMapper secondary : expandable.getSecondaryMappers()) {
                secondary.insertEquationData(interpolator.getInterpolatedSecondaryState(index), y);
                ++index;
            }


            // evaluate the derivative

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