| /* |
| * 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.nonstiff; |
| |
| import org.apache.commons.math3.Field; |
| import org.apache.commons.math3.RealFieldElement; |
| import org.apache.commons.math3.ode.FirstOrderFieldDifferentialEquations; |
| import org.apache.commons.math3.ode.FieldODEState; |
| import org.apache.commons.math3.ode.FieldODEStateAndDerivative; |
| import org.apache.commons.math3.ode.events.Action; |
| import org.apache.commons.math3.ode.events.FieldEventHandler; |
| import org.apache.commons.math3.util.MathArrays; |
| |
| |
| public class StepFieldProblem<T extends RealFieldElement<T>> |
| implements FirstOrderFieldDifferentialEquations<T>, FieldEventHandler<T> { |
| |
| public StepFieldProblem(Field<T> field, T rateBefore, T rateAfter, T switchTime) { |
| this.field = field; |
| this.rateAfter = rateAfter; |
| this.switchTime = switchTime; |
| setRate(rateBefore); |
| } |
| |
| public T[] computeDerivatives(T t, T[] y) { |
| T[] yDot = MathArrays.buildArray(field, 1); |
| yDot[0] = rate; |
| return yDot; |
| } |
| |
| public int getDimension() { |
| return 1; |
| } |
| |
| public void setRate(T rate) { |
| this.rate = rate; |
| } |
| |
| public void init(T t0, T[] y0, T t) { |
| } |
| |
| public void init(FieldODEStateAndDerivative<T> state0, T t) { |
| } |
| |
| public Action eventOccurred(FieldODEStateAndDerivative<T> state, boolean increasing) { |
| setRate(rateAfter); |
| return Action.RESET_DERIVATIVES; |
| } |
| |
| public T g(FieldODEStateAndDerivative<T> state) { |
| return state.getTime().subtract(switchTime); |
| } |
| |
| public FieldODEState<T> resetState(FieldODEStateAndDerivative<T> state) { |
| return state; |
| } |
| |
| private Field<T> field; |
| private T rate; |
| private T rateAfter; |
| private T switchTime; |
| |
| } |