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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;

import java.util.Collection;

import org.apache.commons.math3.RealFieldElement;
import org.apache.commons.math3.analysis.solvers.BracketedRealFieldUnivariateSolver;
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.ode.events.FieldEventHandler;
import org.apache.commons.math3.ode.sampling.FieldStepHandler;

/** This interface represents a first order integrator for
 * differential equations.

 * 

The classes which are devoted to solve first order differential * equations should implement this interface. The problems which can * be handled should implement the {@link * FirstOrderDifferentialEquations} interface.

* * @see FirstOrderFieldDifferentialEquations * @param the type of the field elements * @since 3.6 */ public interface FirstOrderFieldIntegrator> { /** Get the name of the method. * @return name of the method */ String getName(); /** Add a step handler to this integrator. *

The handler will be called by the integrator for each accepted * step.

* @param handler handler for the accepted steps * @see #getStepHandlers() * @see #clearStepHandlers() */ void addStepHandler(FieldStepHandler handler); /** Get all the step handlers that have been added to the integrator. * @return an unmodifiable collection of the added events handlers * @see #addStepHandler(FieldStepHandler) * @see #clearStepHandlers() */ Collection> getStepHandlers(); /** Remove all the step handlers that have been added to the integrator. * @see #addStepHandler(FieldStepHandler) * @see #getStepHandlers() */ void clearStepHandlers(); /** Add an event handler to the integrator. *

* The default solver is a 5th order {@link * org.apache.commons.math3.analysis.solvers.FieldBracketingNthOrderBrentSolver}. *

* @param handler event handler * @param maxCheckInterval maximal time interval between switching * function checks (this interval prevents missing sign changes in * case the integration steps becomes very large) * @param convergence convergence threshold in the event time search * @param maxIterationCount upper limit of the iteration count in * the event time search events. * @see #addEventHandler(FieldEventHandler, double, double, int, * org.apache.commons.math3.analysis.solvers.BracketedRealFieldUnivariateSolver) * @see #getEventHandlers() * @see #clearEventHandlers() */ void addEventHandler(FieldEventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount); /** Add an event handler to the integrator. * @param handler event handler * @param maxCheckInterval maximal time interval between switching * function checks (this interval prevents missing sign changes in * case the integration steps becomes very large) * @param convergence convergence threshold in the event time search * @param maxIterationCount upper limit of the iteration count in * the event time search events. * @param solver solver to use to locate the event * @see #addEventHandler(FieldEventHandler, double, double, int) * @see #getEventHandlers() * @see #clearEventHandlers() */ void addEventHandler(FieldEventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount, BracketedRealFieldUnivariateSolver solver); /** Get all the event handlers that have been added to the integrator. * @return an unmodifiable collection of the added events handlers * @see #addEventHandler(FieldEventHandler, double, double, int) * @see #clearEventHandlers() */ Collection > getEventHandlers(); /** Remove all the event handlers that have been added to the integrator. * @see #addEventHandler(FieldEventHandler, double, double, int) * @see #getEventHandlers() */ void clearEventHandlers(); /** Get the current value of the step start time ti. *

This method can be called during integration (typically by * the object implementing the {@link FirstOrderDifferentialEquations * differential equations} problem) if the value of the current step that * is attempted is needed.

*

The result is undefined if the method is called outside of * calls to integrate.

* @return current value of the state at step start time ti */ FieldODEStateAndDerivative getCurrentStepStart(); /** Get the current signed value of the integration stepsize. *

This method can be called during integration (typically by * the object implementing the {@link FirstOrderDifferentialEquations * differential equations} problem) if the signed value of the current stepsize * that is tried is needed.

*

The result is undefined if the method is called outside of * calls to integrate.

* @return current signed value of the stepsize */ T getCurrentSignedStepsize(); /** Set the maximal number of differential equations function evaluations. *

The purpose of this method is to avoid infinite loops which can occur * for example when stringent error constraints are set or when lots of * discrete events are triggered, thus leading to many rejected steps.

* @param maxEvaluations maximal number of function evaluations (negative * values are silently converted to maximal integer value, thus representing * almost unlimited evaluations) */ void setMaxEvaluations(int maxEvaluations); /** Get the maximal number of functions evaluations. * @return maximal number of functions evaluations */ int getMaxEvaluations(); /** Get the number of evaluations of the differential equations function. *

* The number of evaluations corresponds to the last call to the * integrate method. It is 0 if the method has not been called yet. *

* @return number of evaluations of the differential equations function */ int getEvaluations(); /** Integrate the differential equations up to the given time. *

This method solves an Initial Value Problem (IVP).

*

Since this method stores some internal state variables made * available in its public interface during integration ({@link * #getCurrentSignedStepsize()}), it is not thread-safe.

* @param equations differential equations to integrate * @param initialState initial state (time, primary and secondary state vectors) * @param finalTime target time for the integration * (can be set to a value smaller than {@code t0} for backward integration) * @return final state, its time will be the same as {@code finalTime} if * integration reached its target, but may be different if some {@link * org.apache.commons.math3.ode.events.FieldEventHandler} stops it at some point. * @exception NumberIsTooSmallException if integration step is too small * @exception MaxCountExceededException if the number of functions evaluations is exceeded * @exception NoBracketingException if the location of an event cannot be bracketed */ FieldODEStateAndDerivative integrate(FieldExpandableODE equations, FieldODEState initialState, T finalTime) throws NumberIsTooSmallException, MaxCountExceededException, NoBracketingException; }




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