Mercurial > hg > de.mpg.mpiwg.itgroup.digilib.plugin
view libs/commons-math-2.1/docs/apidocs/src-html/org/apache/commons/math/ode/jacobians/StepHandlerWithJacobians.html @ 13:cbf34dd4d7e6
commons-math-2.1 added
| author | dwinter |
|---|---|
| date | Tue, 04 Jan 2011 10:02:07 +0100 |
| parents | |
| children |
line wrap: on
line source
<HTML> <BODY BGCOLOR="white"> <PRE> <FONT color="green">001</FONT> /*<a name="line.1"></a> <FONT color="green">002</FONT> * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a> <FONT color="green">003</FONT> * contributor license agreements. See the NOTICE file distributed with<a name="line.3"></a> <FONT color="green">004</FONT> * this work for additional information regarding copyright ownership.<a name="line.4"></a> <FONT color="green">005</FONT> * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a> <FONT color="green">006</FONT> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a> <FONT color="green">007</FONT> * the License. You may obtain a copy of the License at<a name="line.7"></a> <FONT color="green">008</FONT> *<a name="line.8"></a> <FONT color="green">009</FONT> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a> <FONT color="green">010</FONT> *<a name="line.10"></a> <FONT color="green">011</FONT> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a> <FONT color="green">012</FONT> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a> <FONT color="green">013</FONT> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a> <FONT color="green">014</FONT> * See the License for the specific language governing permissions and<a name="line.14"></a> <FONT color="green">015</FONT> * limitations under the License.<a name="line.15"></a> <FONT color="green">016</FONT> */<a name="line.16"></a> <FONT color="green">017</FONT> <a name="line.17"></a> <FONT color="green">018</FONT> package org.apache.commons.math.ode.jacobians;<a name="line.18"></a> <FONT color="green">019</FONT> <a name="line.19"></a> <FONT color="green">020</FONT> import org.apache.commons.math.ode.DerivativeException;<a name="line.20"></a> <FONT color="green">021</FONT> <a name="line.21"></a> <FONT color="green">022</FONT> /**<a name="line.22"></a> <FONT color="green">023</FONT> * This interface represents a handler that should be called after<a name="line.23"></a> <FONT color="green">024</FONT> * each successful step.<a name="line.24"></a> <FONT color="green">025</FONT> *<a name="line.25"></a> <FONT color="green">026</FONT> * <p>The ODE integrators compute the evolution of the state vector at<a name="line.26"></a> <FONT color="green">027</FONT> * some grid points that depend on their own internal algorithm. Once<a name="line.27"></a> <FONT color="green">028</FONT> * they have found a new grid point (possibly after having computed<a name="line.28"></a> <FONT color="green">029</FONT> * several evaluation of the derivative at intermediate points), they<a name="line.29"></a> <FONT color="green">030</FONT> * provide it to objects implementing this interface. These objects<a name="line.30"></a> <FONT color="green">031</FONT> * typically either ignore the intermediate steps and wait for the<a name="line.31"></a> <FONT color="green">032</FONT> * last one, store the points in an ephemeris, or forward them to<a name="line.32"></a> <FONT color="green">033</FONT> * specialized processing or output methods.</p><a name="line.33"></a> <FONT color="green">034</FONT> *<a name="line.34"></a> <FONT color="green">035</FONT> * <p>Note that is is possible to register a {@link<a name="line.35"></a> <FONT color="green">036</FONT> * org.apache.commons.math.ode.sampling.StepHandler classical step handler}<a name="line.36"></a> <FONT color="green">037</FONT> * in the low level integrator used to build a {@link FirstOrderIntegratorWithJacobians}<a name="line.37"></a> <FONT color="green">038</FONT> * rather than implementing this class. The step handlers registered at low level<a name="line.38"></a> <FONT color="green">039</FONT> * will see the big compound state whether the step handlers defined by this interface<a name="line.39"></a> <FONT color="green">040</FONT> * see the original state, and its jacobians in separate arrays.</p><a name="line.40"></a> <FONT color="green">041</FONT> *<a name="line.41"></a> <FONT color="green">042</FONT> * <p>The compound state is guaranteed to contain the original state in the first<a name="line.42"></a> <FONT color="green">043</FONT> * elements, followed by the jacobian with respect to initial state (in row order),<a name="line.43"></a> <FONT color="green">044</FONT> * followed by the jacobian with respect to parameters (in row order). If for example<a name="line.44"></a> <FONT color="green">045</FONT> * the original state dimension is 6 and there are 3 parameters, the compound state will<a name="line.45"></a> <FONT color="green">046</FONT> * be a 60 elements array. The first 6 elements will be the original state, the next 36<a name="line.46"></a> <FONT color="green">047</FONT> * elements will be the jacobian with respect to initial state, and the remaining 18 elements<a name="line.47"></a> <FONT color="green">048</FONT> * will be the jacobian with respect to parameters.</p><a name="line.48"></a> <FONT color="green">049</FONT> *<a name="line.49"></a> <FONT color="green">050</FONT> * <p>Dealing with low level step handlers is cumbersome if one really needs the jacobians<a name="line.50"></a> <FONT color="green">051</FONT> * in these methods, but it also prevents many data being copied back and forth between<a name="line.51"></a> <FONT color="green">052</FONT> * state and jacobians on one side and compound state on the other side. So for performance<a name="line.52"></a> <FONT color="green">053</FONT> * reasons, it is recommended to use this interface <em>only</em> if jacobians are really<a name="line.53"></a> <FONT color="green">054</FONT> * needed and to use lower level handlers if only state is needed.</p><a name="line.54"></a> <FONT color="green">055</FONT> *<a name="line.55"></a> <FONT color="green">056</FONT> * @see FirstOrderIntegratorWithJacobians<a name="line.56"></a> <FONT color="green">057</FONT> * @see StepInterpolatorWithJacobians<a name="line.57"></a> <FONT color="green">058</FONT> * @version $Revision: 920131 $ $Date: 2010-03-07 17:19:18 -0500 (Sun, 07 Mar 2010) $<a name="line.58"></a> <FONT color="green">059</FONT> * @since 2.1<a name="line.59"></a> <FONT color="green">060</FONT> */<a name="line.60"></a> <FONT color="green">061</FONT> <a name="line.61"></a> <FONT color="green">062</FONT> public interface StepHandlerWithJacobians {<a name="line.62"></a> <FONT color="green">063</FONT> <a name="line.63"></a> <FONT color="green">064</FONT> /** Determines whether this handler needs dense output.<a name="line.64"></a> <FONT color="green">065</FONT> * <p>This method allows the integrator to avoid performing extra<a name="line.65"></a> <FONT color="green">066</FONT> * computation if the handler does not need dense output.</p><a name="line.66"></a> <FONT color="green">067</FONT> * @return true if the handler needs dense output<a name="line.67"></a> <FONT color="green">068</FONT> */<a name="line.68"></a> <FONT color="green">069</FONT> boolean requiresDenseOutput();<a name="line.69"></a> <FONT color="green">070</FONT> <a name="line.70"></a> <FONT color="green">071</FONT> /** Reset the step handler.<a name="line.71"></a> <FONT color="green">072</FONT> * Initialize the internal data as required before the first step is<a name="line.72"></a> <FONT color="green">073</FONT> * handled.<a name="line.73"></a> <FONT color="green">074</FONT> */<a name="line.74"></a> <FONT color="green">075</FONT> void reset();<a name="line.75"></a> <FONT color="green">076</FONT> <a name="line.76"></a> <FONT color="green">077</FONT> /**<a name="line.77"></a> <FONT color="green">078</FONT> * Handle the last accepted step<a name="line.78"></a> <FONT color="green">079</FONT> * @param interpolator interpolator for the last accepted step. For<a name="line.79"></a> <FONT color="green">080</FONT> * efficiency purposes, the various integrators reuse the same<a name="line.80"></a> <FONT color="green">081</FONT> * object on each call, so if the instance wants to keep it across<a name="line.81"></a> <FONT color="green">082</FONT> * all calls (for example to provide at the end of the integration a<a name="line.82"></a> <FONT color="green">083</FONT> * continuous model valid throughout the integration range, as the<a name="line.83"></a> <FONT color="green">084</FONT> * {@link org.apache.commons.math.ode.ContinuousOutputModel<a name="line.84"></a> <FONT color="green">085</FONT> * ContinuousOutputModel} class does), it should build a local copy<a name="line.85"></a> <FONT color="green">086</FONT> * using the clone method of the interpolator and store this copy.<a name="line.86"></a> <FONT color="green">087</FONT> * Keeping only a reference to the interpolator and reusing it will<a name="line.87"></a> <FONT color="green">088</FONT> * result in unpredictable behavior (potentially crashing the application).<a name="line.88"></a> <FONT color="green">089</FONT> * @param isLast true if the step is the last one<a name="line.89"></a> <FONT color="green">090</FONT> * @throws DerivativeException this exception is propagated to the<a name="line.90"></a> <FONT color="green">091</FONT> * caller if the underlying user function triggers one<a name="line.91"></a> <FONT color="green">092</FONT> */<a name="line.92"></a> <FONT color="green">093</FONT> void handleStep(StepInterpolatorWithJacobians interpolator, boolean isLast) throws DerivativeException;<a name="line.93"></a> <FONT color="green">094</FONT> <a name="line.94"></a> <FONT color="green">095</FONT> }<a name="line.95"></a> </PRE> </BODY> </HTML>