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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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package org.apache.commons.math.ode;
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/** This interface represents a first order differential equations set.
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* <p>This interface should be implemented by all real first order
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* differential equation problems before they can be handled by the
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* integrators {@link FirstOrderIntegrator#integrate} method.</p>
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* <p>A first order differential equations problem, as seen by an
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* integrator is the time derivative <code>dY/dt</code> of a state
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* vector <code>Y</code>, both being one dimensional arrays. From the
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* integrator point of view, this derivative depends only on the
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* current time <code>t</code> and on the state vector
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* <p>For real problems, the derivative depends also on parameters
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* that do not belong to the state vector (dynamical model constants
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* for example). These constants are completely outside of the scope
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* of this interface, the classes that implement it are allowed to
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* handle them as they want.</p>
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* @see FirstOrderIntegrator
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* @see FirstOrderConverter
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* @see SecondOrderDifferentialEquations
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* @version $Revision: 786881 $ $Date: 2009-06-20 14:53:08 -0400 (Sat, 20 Jun 2009) $
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public interface FirstOrderDifferentialEquations {
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/** Get the dimension of the problem.
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* @return dimension of the problem
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public int getDimension();
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/** Get the current time derivative of the state vector.
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* @param t current value of the independent <I>time</I> variable
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* @param y array containing the current value of the state vector
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* @param yDot placeholder array where to put the time derivative of the state vector
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* @throws DerivativeException this exception is propagated to the caller if the
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* underlying user function triggers one
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public void computeDerivatives(double t, double[] y, double[] yDot)
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throws DerivativeException;