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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* 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
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math3.ode;
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;
import java.util.Collection;
/**
* This interface represents a first order integrator for differential equations.
*
* <p>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 <T> the type of the field elements
* @since 3.6
*/
public interface FirstOrderFieldIntegrator<T extends RealFieldElement<T>> {
/**
* Get the name of the method.
*
* @return name of the method
*/
String getName();
/**
* Add a step handler to this integrator.
*
* <p>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<T> 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<FieldStepHandler<T>> 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.
*
* <p>The default solver is a 5<sup>th</sup> 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<T> 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<T> handler,
double maxCheckInterval,
double convergence,
int maxIterationCount,
BracketedRealFieldUnivariateSolver<T> 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<FieldEventHandler<T>> 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 t<sub>i</sub>.
*
* <p>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.
*
* <p>The result is undefined if the method is called outside of calls to <code>integrate</code>
* .
*
* @return current value of the state at step start time t<sub>i</sub>
*/
FieldODEStateAndDerivative<T> getCurrentStepStart();
/**
* Get the current signed value of the integration stepsize.
*
* <p>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.
*
* <p>The result is undefined if the method is called outside of calls to <code>integrate</code>
* .
*
* @return current signed value of the stepsize
*/
T getCurrentSignedStepsize();
/**
* Set the maximal number of differential equations function evaluations.
*
* <p>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.
*
* <p>The number of evaluations corresponds to the last call to the <code>integrate</code>
* 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.
*
* <p>This method solves an Initial Value Problem (IVP).
*
* <p>Since this method stores some internal state variables made available in its public
* interface during integration ({@link #getCurrentSignedStepsize()}), it is <em>not</em>
* 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<T> integrate(
FieldExpandableODE<T> equations, FieldODEState<T> initialState, T finalTime)
throws NumberIsTooSmallException, MaxCountExceededException, NoBracketingException;
}
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