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 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
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package org.apache.commons.math3.ode.nonstiff;

import org.apache.commons.math3.Field;
import org.apache.commons.math3.RealFieldElement;
import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.MaxCountExceededException;
import org.apache.commons.math3.exception.NoBracketingException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.linear.Array2DRowFieldMatrix;
import org.apache.commons.math3.ode.FieldExpandableODE;
import org.apache.commons.math3.ode.FieldODEState;
import org.apache.commons.math3.ode.FieldODEStateAndDerivative;
import org.apache.commons.math3.ode.MultistepFieldIntegrator;


Base class for Adams-Bashforth and Adams-Moulton integrators.
Type parameters:
  • <T> – the type of the field elements
Since:3.6
/** Base class for {@link AdamsBashforthFieldIntegrator Adams-Bashforth} and * {@link AdamsMoultonFieldIntegrator Adams-Moulton} integrators. * @param <T> the type of the field elements * @since 3.6 */
public abstract class AdamsFieldIntegrator<T extends RealFieldElement<T>> extends MultistepFieldIntegrator<T> {
Transformer.
/** Transformer. */
private final AdamsNordsieckFieldTransformer<T> transformer;
Build an Adams integrator with the given order and step control parameters.
Params:
  • field – field to which the time and state vector elements belong
  • name – name of the method
  • nSteps – number of steps of the method excluding the one being computed
  • order – order of the method
  • minStep – minimal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
  • maxStep – maximal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
  • scalAbsoluteTolerance – allowed absolute error
  • scalRelativeTolerance – allowed relative error
Throws:
/** * Build an Adams integrator with the given order and step control parameters. * @param field field to which the time and state vector elements belong * @param name name of the method * @param nSteps number of steps of the method excluding the one being computed * @param order order of the method * @param minStep minimal step (sign is irrelevant, regardless of * integration direction, forward or backward), the last step can * be smaller than this * @param maxStep maximal step (sign is irrelevant, regardless of * integration direction, forward or backward), the last step can * be smaller than this * @param scalAbsoluteTolerance allowed absolute error * @param scalRelativeTolerance allowed relative error * @exception NumberIsTooSmallException if order is 1 or less */
public AdamsFieldIntegrator(final Field<T> field, final String name, final int nSteps, final int order, final double minStep, final double maxStep, final double scalAbsoluteTolerance, final double scalRelativeTolerance) throws NumberIsTooSmallException { super(field, name, nSteps, order, minStep, maxStep, scalAbsoluteTolerance, scalRelativeTolerance); transformer = AdamsNordsieckFieldTransformer.getInstance(field, nSteps); }
Build an Adams integrator with the given order and step control parameters.
Params:
  • field – field to which the time and state vector elements belong
  • name – name of the method
  • nSteps – number of steps of the method excluding the one being computed
  • order – order of the method
  • minStep – minimal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
  • maxStep – maximal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
  • vecAbsoluteTolerance – allowed absolute error
  • vecRelativeTolerance – allowed relative error
Throws:
/** * Build an Adams integrator with the given order and step control parameters. * @param field field to which the time and state vector elements belong * @param name name of the method * @param nSteps number of steps of the method excluding the one being computed * @param order order of the method * @param minStep minimal step (sign is irrelevant, regardless of * integration direction, forward or backward), the last step can * be smaller than this * @param maxStep maximal step (sign is irrelevant, regardless of * integration direction, forward or backward), the last step can * be smaller than this * @param vecAbsoluteTolerance allowed absolute error * @param vecRelativeTolerance allowed relative error * @exception IllegalArgumentException if order is 1 or less */
public AdamsFieldIntegrator(final Field<T> field, final String name, final int nSteps, final int order, final double minStep, final double maxStep, final double[] vecAbsoluteTolerance, final double[] vecRelativeTolerance) throws IllegalArgumentException { super(field, name, nSteps, order, minStep, maxStep, vecAbsoluteTolerance, vecRelativeTolerance); transformer = AdamsNordsieckFieldTransformer.getInstance(field, nSteps); }
{@inheritDoc}
/** {@inheritDoc} */
public abstract FieldODEStateAndDerivative<T> integrate(final FieldExpandableODE<T> equations, final FieldODEState<T> initialState, final T finalTime) throws NumberIsTooSmallException, DimensionMismatchException, MaxCountExceededException, NoBracketingException;
{@inheritDoc}
/** {@inheritDoc} */
@Override protected Array2DRowFieldMatrix<T> initializeHighOrderDerivatives(final T h, final T[] t, final T[][] y, final T[][] yDot) { return transformer.initializeHighOrderDerivatives(h, t, y, yDot); }
Update the high order scaled derivatives for Adams integrators (phase 1).

The complete update of high order derivatives has a form similar to:

rn+1 = (s1(n) - s1(n+1)) P-1 u + P-1 A P rn
this method computes the P-1 A P rn part.

Params:
  • highOrder – high order scaled derivatives (h2/2 y'', ... hk/k! y(k))
See Also:
Returns:updated high order derivatives
/** Update the high order scaled derivatives for Adams integrators (phase 1). * <p>The complete update of high order derivatives has a form similar to: * <pre> * r<sub>n+1</sub> = (s<sub>1</sub>(n) - s<sub>1</sub>(n+1)) P<sup>-1</sup> u + P<sup>-1</sup> A P r<sub>n</sub> * </pre> * this method computes the P<sup>-1</sup> A P r<sub>n</sub> part.</p> * @param highOrder high order scaled derivatives * (h<sup>2</sup>/2 y'', ... h<sup>k</sup>/k! y(k)) * @return updated high order derivatives * @see #updateHighOrderDerivativesPhase2(RealFieldElement[], RealFieldElement[], Array2DRowFieldMatrix) */
public Array2DRowFieldMatrix<T> updateHighOrderDerivativesPhase1(final Array2DRowFieldMatrix<T> highOrder) { return transformer.updateHighOrderDerivativesPhase1(highOrder); }
Update the high order scaled derivatives Adams integrators (phase 2).

The complete update of high order derivatives has a form similar to:

rn+1 = (s1(n) - s1(n+1)) P-1 u + P-1 A P rn
this method computes the (s1(n) - s1(n+1)) P-1 u part.

Phase 1 of the update must already have been performed.

Params:
  • start – first order scaled derivatives at step start
  • end – first order scaled derivatives at step end
  • highOrder – high order scaled derivatives, will be modified (h2/2 y'', ... hk/k! y(k))
See Also:
/** Update the high order scaled derivatives Adams integrators (phase 2). * <p>The complete update of high order derivatives has a form similar to: * <pre> * r<sub>n+1</sub> = (s<sub>1</sub>(n) - s<sub>1</sub>(n+1)) P<sup>-1</sup> u + P<sup>-1</sup> A P r<sub>n</sub> * </pre> * this method computes the (s<sub>1</sub>(n) - s<sub>1</sub>(n+1)) P<sup>-1</sup> u part.</p> * <p>Phase 1 of the update must already have been performed.</p> * @param start first order scaled derivatives at step start * @param end first order scaled derivatives at step end * @param highOrder high order scaled derivatives, will be modified * (h<sup>2</sup>/2 y'', ... h<sup>k</sup>/k! y(k)) * @see #updateHighOrderDerivativesPhase1(Array2DRowFieldMatrix) */
public void updateHighOrderDerivativesPhase2(final T[] start, final T[] end, final Array2DRowFieldMatrix<T> highOrder) { transformer.updateHighOrderDerivativesPhase2(start, end, highOrder); } }