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Diffstat (limited to 'src/main/java/org/apache/commons/math/ode/nonstiff/EulerIntegrator.java')
-rw-r--r-- | src/main/java/org/apache/commons/math/ode/nonstiff/EulerIntegrator.java | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/ode/nonstiff/EulerIntegrator.java b/src/main/java/org/apache/commons/math/ode/nonstiff/EulerIntegrator.java new file mode 100644 index 0000000..21b0f74 --- /dev/null +++ b/src/main/java/org/apache/commons/math/ode/nonstiff/EulerIntegrator.java @@ -0,0 +1,72 @@ +/* + * 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.math.ode.nonstiff; + + +/** + * This class implements a simple Euler integrator for Ordinary + * Differential Equations. + * + * <p>The Euler algorithm is the simplest one that can be used to + * integrate ordinary differential equations. It is a simple inversion + * of the forward difference expression : + * <code>f'=(f(t+h)-f(t))/h</code> which leads to + * <code>f(t+h)=f(t)+hf'</code>. The interpolation scheme used for + * dense output is the linear scheme already used for integration.</p> + * + * <p>This algorithm looks cheap because it needs only one function + * evaluation per step. However, as it uses linear estimates, it needs + * very small steps to achieve high accuracy, and small steps lead to + * numerical errors and instabilities.</p> + * + * <p>This algorithm is almost never used and has been included in + * this package only as a comparison reference for more useful + * integrators.</p> + * + * @see MidpointIntegrator + * @see ClassicalRungeKuttaIntegrator + * @see GillIntegrator + * @see ThreeEighthesIntegrator + * @version $Revision: 810196 $ $Date: 2009-09-01 21:47:46 +0200 (mar. 01 sept. 2009) $ + * @since 1.2 + */ + +public class EulerIntegrator extends RungeKuttaIntegrator { + + /** Time steps Butcher array. */ + private static final double[] STATIC_C = { + }; + + /** Internal weights Butcher array. */ + private static final double[][] STATIC_A = { + }; + + /** Propagation weights Butcher array. */ + private static final double[] STATIC_B = { + 1.0 + }; + + /** Simple constructor. + * Build an Euler integrator with the given step. + * @param step integration step + */ + public EulerIntegrator(final double step) { + super("Euler", STATIC_C, STATIC_A, STATIC_B, new EulerStepInterpolator(), step); + } + +} |