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commons-math-2.1 added
| author | dwinter |
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| date | Tue, 04 Jan 2011 10:02:07 +0100 |
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<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.events;<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.ConvergenceException;<a name="line.20"></a> <FONT color="green">021</FONT> import org.apache.commons.math.FunctionEvaluationException;<a name="line.21"></a> <FONT color="green">022</FONT> import org.apache.commons.math.MathRuntimeException;<a name="line.22"></a> <FONT color="green">023</FONT> import org.apache.commons.math.analysis.UnivariateRealFunction;<a name="line.23"></a> <FONT color="green">024</FONT> import org.apache.commons.math.analysis.solvers.BrentSolver;<a name="line.24"></a> <FONT color="green">025</FONT> import org.apache.commons.math.ode.DerivativeException;<a name="line.25"></a> <FONT color="green">026</FONT> import org.apache.commons.math.ode.sampling.StepInterpolator;<a name="line.26"></a> <FONT color="green">027</FONT> <a name="line.27"></a> <FONT color="green">028</FONT> /** This class handles the state for one {@link EventHandler<a name="line.28"></a> <FONT color="green">029</FONT> * event handler} during integration steps.<a name="line.29"></a> <FONT color="green">030</FONT> *<a name="line.30"></a> <FONT color="green">031</FONT> * <p>Each time the integrator proposes a step, the event handler<a name="line.31"></a> <FONT color="green">032</FONT> * switching function should be checked. This class handles the state<a name="line.32"></a> <FONT color="green">033</FONT> * of one handler during one integration step, with references to the<a name="line.33"></a> <FONT color="green">034</FONT> * state at the end of the preceding step. This information is used to<a name="line.34"></a> <FONT color="green">035</FONT> * decide if the handler should trigger an event or not during the<a name="line.35"></a> <FONT color="green">036</FONT> * proposed step (and hence the step should be reduced to ensure the<a name="line.36"></a> <FONT color="green">037</FONT> * event occurs at a bound rather than inside the step).</p><a name="line.37"></a> <FONT color="green">038</FONT> *<a name="line.38"></a> <FONT color="green">039</FONT> * @version $Revision: 889006 $ $Date: 2009-12-09 17:46:36 -0500 (Wed, 09 Dec 2009) $<a name="line.39"></a> <FONT color="green">040</FONT> * @since 1.2<a name="line.40"></a> <FONT color="green">041</FONT> */<a name="line.41"></a> <FONT color="green">042</FONT> public class EventState {<a name="line.42"></a> <FONT color="green">043</FONT> <a name="line.43"></a> <FONT color="green">044</FONT> /** Event handler. */<a name="line.44"></a> <FONT color="green">045</FONT> private final EventHandler handler;<a name="line.45"></a> <FONT color="green">046</FONT> <a name="line.46"></a> <FONT color="green">047</FONT> /** Maximal time interval between events handler checks. */<a name="line.47"></a> <FONT color="green">048</FONT> private final double maxCheckInterval;<a name="line.48"></a> <FONT color="green">049</FONT> <a name="line.49"></a> <FONT color="green">050</FONT> /** Convergence threshold for event localization. */<a name="line.50"></a> <FONT color="green">051</FONT> private final double convergence;<a name="line.51"></a> <FONT color="green">052</FONT> <a name="line.52"></a> <FONT color="green">053</FONT> /** Upper limit in the iteration count for event localization. */<a name="line.53"></a> <FONT color="green">054</FONT> private final int maxIterationCount;<a name="line.54"></a> <FONT color="green">055</FONT> <a name="line.55"></a> <FONT color="green">056</FONT> /** Time at the beginning of the step. */<a name="line.56"></a> <FONT color="green">057</FONT> private double t0;<a name="line.57"></a> <FONT color="green">058</FONT> <a name="line.58"></a> <FONT color="green">059</FONT> /** Value of the events handler at the beginning of the step. */<a name="line.59"></a> <FONT color="green">060</FONT> private double g0;<a name="line.60"></a> <FONT color="green">061</FONT> <a name="line.61"></a> <FONT color="green">062</FONT> /** Simulated sign of g0 (we cheat when crossing events). */<a name="line.62"></a> <FONT color="green">063</FONT> private boolean g0Positive;<a name="line.63"></a> <FONT color="green">064</FONT> <a name="line.64"></a> <FONT color="green">065</FONT> /** Indicator of event expected during the step. */<a name="line.65"></a> <FONT color="green">066</FONT> private boolean pendingEvent;<a name="line.66"></a> <FONT color="green">067</FONT> <a name="line.67"></a> <FONT color="green">068</FONT> /** Occurrence time of the pending event. */<a name="line.68"></a> <FONT color="green">069</FONT> private double pendingEventTime;<a name="line.69"></a> <FONT color="green">070</FONT> <a name="line.70"></a> <FONT color="green">071</FONT> /** Occurrence time of the previous event. */<a name="line.71"></a> <FONT color="green">072</FONT> private double previousEventTime;<a name="line.72"></a> <FONT color="green">073</FONT> <a name="line.73"></a> <FONT color="green">074</FONT> /** Integration direction. */<a name="line.74"></a> <FONT color="green">075</FONT> private boolean forward;<a name="line.75"></a> <FONT color="green">076</FONT> <a name="line.76"></a> <FONT color="green">077</FONT> /** Variation direction around pending event.<a name="line.77"></a> <FONT color="green">078</FONT> * (this is considered with respect to the integration direction)<a name="line.78"></a> <FONT color="green">079</FONT> */<a name="line.79"></a> <FONT color="green">080</FONT> private boolean increasing;<a name="line.80"></a> <FONT color="green">081</FONT> <a name="line.81"></a> <FONT color="green">082</FONT> /** Next action indicator. */<a name="line.82"></a> <FONT color="green">083</FONT> private int nextAction;<a name="line.83"></a> <FONT color="green">084</FONT> <a name="line.84"></a> <FONT color="green">085</FONT> /** Simple constructor.<a name="line.85"></a> <FONT color="green">086</FONT> * @param handler event handler<a name="line.86"></a> <FONT color="green">087</FONT> * @param maxCheckInterval maximal time interval between switching<a name="line.87"></a> <FONT color="green">088</FONT> * function checks (this interval prevents missing sign changes in<a name="line.88"></a> <FONT color="green">089</FONT> * case the integration steps becomes very large)<a name="line.89"></a> <FONT color="green">090</FONT> * @param convergence convergence threshold in the event time search<a name="line.90"></a> <FONT color="green">091</FONT> * @param maxIterationCount upper limit of the iteration count in<a name="line.91"></a> <FONT color="green">092</FONT> * the event time search<a name="line.92"></a> <FONT color="green">093</FONT> */<a name="line.93"></a> <FONT color="green">094</FONT> public EventState(final EventHandler handler, final double maxCheckInterval,<a name="line.94"></a> <FONT color="green">095</FONT> final double convergence, final int maxIterationCount) {<a name="line.95"></a> <FONT color="green">096</FONT> this.handler = handler;<a name="line.96"></a> <FONT color="green">097</FONT> this.maxCheckInterval = maxCheckInterval;<a name="line.97"></a> <FONT color="green">098</FONT> this.convergence = Math.abs(convergence);<a name="line.98"></a> <FONT color="green">099</FONT> this.maxIterationCount = maxIterationCount;<a name="line.99"></a> <FONT color="green">100</FONT> <a name="line.100"></a> <FONT color="green">101</FONT> // some dummy values ...<a name="line.101"></a> <FONT color="green">102</FONT> t0 = Double.NaN;<a name="line.102"></a> <FONT color="green">103</FONT> g0 = Double.NaN;<a name="line.103"></a> <FONT color="green">104</FONT> g0Positive = true;<a name="line.104"></a> <FONT color="green">105</FONT> pendingEvent = false;<a name="line.105"></a> <FONT color="green">106</FONT> pendingEventTime = Double.NaN;<a name="line.106"></a> <FONT color="green">107</FONT> previousEventTime = Double.NaN;<a name="line.107"></a> <FONT color="green">108</FONT> increasing = true;<a name="line.108"></a> <FONT color="green">109</FONT> nextAction = EventHandler.CONTINUE;<a name="line.109"></a> <FONT color="green">110</FONT> <a name="line.110"></a> <FONT color="green">111</FONT> }<a name="line.111"></a> <FONT color="green">112</FONT> <a name="line.112"></a> <FONT color="green">113</FONT> /** Get the underlying event handler.<a name="line.113"></a> <FONT color="green">114</FONT> * @return underlying event handler<a name="line.114"></a> <FONT color="green">115</FONT> */<a name="line.115"></a> <FONT color="green">116</FONT> public EventHandler getEventHandler() {<a name="line.116"></a> <FONT color="green">117</FONT> return handler;<a name="line.117"></a> <FONT color="green">118</FONT> }<a name="line.118"></a> <FONT color="green">119</FONT> <a name="line.119"></a> <FONT color="green">120</FONT> /** Get the maximal time interval between events handler checks.<a name="line.120"></a> <FONT color="green">121</FONT> * @return maximal time interval between events handler checks<a name="line.121"></a> <FONT color="green">122</FONT> */<a name="line.122"></a> <FONT color="green">123</FONT> public double getMaxCheckInterval() {<a name="line.123"></a> <FONT color="green">124</FONT> return maxCheckInterval;<a name="line.124"></a> <FONT color="green">125</FONT> }<a name="line.125"></a> <FONT color="green">126</FONT> <a name="line.126"></a> <FONT color="green">127</FONT> /** Get the convergence threshold for event localization.<a name="line.127"></a> <FONT color="green">128</FONT> * @return convergence threshold for event localization<a name="line.128"></a> <FONT color="green">129</FONT> */<a name="line.129"></a> <FONT color="green">130</FONT> public double getConvergence() {<a name="line.130"></a> <FONT color="green">131</FONT> return convergence;<a name="line.131"></a> <FONT color="green">132</FONT> }<a name="line.132"></a> <FONT color="green">133</FONT> <a name="line.133"></a> <FONT color="green">134</FONT> /** Get the upper limit in the iteration count for event localization.<a name="line.134"></a> <FONT color="green">135</FONT> * @return upper limit in the iteration count for event localization<a name="line.135"></a> <FONT color="green">136</FONT> */<a name="line.136"></a> <FONT color="green">137</FONT> public int getMaxIterationCount() {<a name="line.137"></a> <FONT color="green">138</FONT> return maxIterationCount;<a name="line.138"></a> <FONT color="green">139</FONT> }<a name="line.139"></a> <FONT color="green">140</FONT> <a name="line.140"></a> <FONT color="green">141</FONT> /** Reinitialize the beginning of the step.<a name="line.141"></a> <FONT color="green">142</FONT> * @param tStart value of the independent <i>time</i> variable at the<a name="line.142"></a> <FONT color="green">143</FONT> * beginning of the step<a name="line.143"></a> <FONT color="green">144</FONT> * @param yStart array containing the current value of the state vector<a name="line.144"></a> <FONT color="green">145</FONT> * at the beginning of the step<a name="line.145"></a> <FONT color="green">146</FONT> * @exception EventException if the event handler<a name="line.146"></a> <FONT color="green">147</FONT> * value cannot be evaluated at the beginning of the step<a name="line.147"></a> <FONT color="green">148</FONT> */<a name="line.148"></a> <FONT color="green">149</FONT> public void reinitializeBegin(final double tStart, final double[] yStart)<a name="line.149"></a> <FONT color="green">150</FONT> throws EventException {<a name="line.150"></a> <FONT color="green">151</FONT> t0 = tStart;<a name="line.151"></a> <FONT color="green">152</FONT> g0 = handler.g(tStart, yStart);<a name="line.152"></a> <FONT color="green">153</FONT> g0Positive = g0 >= 0;<a name="line.153"></a> <FONT color="green">154</FONT> }<a name="line.154"></a> <FONT color="green">155</FONT> <a name="line.155"></a> <FONT color="green">156</FONT> /** Evaluate the impact of the proposed step on the event handler.<a name="line.156"></a> <FONT color="green">157</FONT> * @param interpolator step interpolator for the proposed step<a name="line.157"></a> <FONT color="green">158</FONT> * @return true if the event handler triggers an event before<a name="line.158"></a> <FONT color="green">159</FONT> * the end of the proposed step (this implies the step should be<a name="line.159"></a> <FONT color="green">160</FONT> * rejected)<a name="line.160"></a> <FONT color="green">161</FONT> * @exception DerivativeException if the interpolator fails to<a name="line.161"></a> <FONT color="green">162</FONT> * compute the switching function somewhere within the step<a name="line.162"></a> <FONT color="green">163</FONT> * @exception EventException if the switching function<a name="line.163"></a> <FONT color="green">164</FONT> * cannot be evaluated<a name="line.164"></a> <FONT color="green">165</FONT> * @exception ConvergenceException if an event cannot be located<a name="line.165"></a> <FONT color="green">166</FONT> */<a name="line.166"></a> <FONT color="green">167</FONT> public boolean evaluateStep(final StepInterpolator interpolator)<a name="line.167"></a> <FONT color="green">168</FONT> throws DerivativeException, EventException, ConvergenceException {<a name="line.168"></a> <FONT color="green">169</FONT> <a name="line.169"></a> <FONT color="green">170</FONT> try {<a name="line.170"></a> <FONT color="green">171</FONT> <a name="line.171"></a> <FONT color="green">172</FONT> forward = interpolator.isForward();<a name="line.172"></a> <FONT color="green">173</FONT> final double t1 = interpolator.getCurrentTime();<a name="line.173"></a> <FONT color="green">174</FONT> final int n = Math.max(1, (int) Math.ceil(Math.abs(t1 - t0) / maxCheckInterval));<a name="line.174"></a> <FONT color="green">175</FONT> final double h = (t1 - t0) / n;<a name="line.175"></a> <FONT color="green">176</FONT> <a name="line.176"></a> <FONT color="green">177</FONT> double ta = t0;<a name="line.177"></a> <FONT color="green">178</FONT> double ga = g0;<a name="line.178"></a> <FONT color="green">179</FONT> double tb = t0 + (interpolator.isForward() ? convergence : -convergence);<a name="line.179"></a> <FONT color="green">180</FONT> for (int i = 0; i < n; ++i) {<a name="line.180"></a> <FONT color="green">181</FONT> <a name="line.181"></a> <FONT color="green">182</FONT> // evaluate handler value at the end of the substep<a name="line.182"></a> <FONT color="green">183</FONT> tb += h;<a name="line.183"></a> <FONT color="green">184</FONT> interpolator.setInterpolatedTime(tb);<a name="line.184"></a> <FONT color="green">185</FONT> final double gb = handler.g(tb, interpolator.getInterpolatedState());<a name="line.185"></a> <FONT color="green">186</FONT> <a name="line.186"></a> <FONT color="green">187</FONT> // check events occurrence<a name="line.187"></a> <FONT color="green">188</FONT> if (g0Positive ^ (gb >= 0)) {<a name="line.188"></a> <FONT color="green">189</FONT> // there is a sign change: an event is expected during this step<a name="line.189"></a> <FONT color="green">190</FONT> <a name="line.190"></a> <FONT color="green">191</FONT> if (ga * gb > 0) {<a name="line.191"></a> <FONT color="green">192</FONT> // this is a corner case:<a name="line.192"></a> <FONT color="green">193</FONT> // - there was an event near ta,<a name="line.193"></a> <FONT color="green">194</FONT> // - there is another event between ta and tb<a name="line.194"></a> <FONT color="green">195</FONT> // - when ta was computed, convergence was reached on the "wrong side" of the interval<a name="line.195"></a> <FONT color="green">196</FONT> // this implies that the real sign of ga is the same as gb, so we need to slightly<a name="line.196"></a> <FONT color="green">197</FONT> // shift ta to make sure ga and gb get opposite signs and the solver won't complain<a name="line.197"></a> <FONT color="green">198</FONT> // about bracketing<a name="line.198"></a> <FONT color="green">199</FONT> final double epsilon = (forward ? 0.25 : -0.25) * convergence;<a name="line.199"></a> <FONT color="green">200</FONT> for (int k = 0; (k < 4) && (ga * gb > 0); ++k) {<a name="line.200"></a> <FONT color="green">201</FONT> ta += epsilon;<a name="line.201"></a> <FONT color="green">202</FONT> interpolator.setInterpolatedTime(ta);<a name="line.202"></a> <FONT color="green">203</FONT> ga = handler.g(ta, interpolator.getInterpolatedState());<a name="line.203"></a> <FONT color="green">204</FONT> }<a name="line.204"></a> <FONT color="green">205</FONT> if (ga * gb > 0) {<a name="line.205"></a> <FONT color="green">206</FONT> // this should never happen<a name="line.206"></a> <FONT color="green">207</FONT> throw MathRuntimeException.createInternalError(null);<a name="line.207"></a> <FONT color="green">208</FONT> }<a name="line.208"></a> <FONT color="green">209</FONT> }<a name="line.209"></a> <FONT color="green">210</FONT> <a name="line.210"></a> <FONT color="green">211</FONT> // variation direction, with respect to the integration direction<a name="line.211"></a> <FONT color="green">212</FONT> increasing = gb >= ga;<a name="line.212"></a> <FONT color="green">213</FONT> <a name="line.213"></a> <FONT color="green">214</FONT> final UnivariateRealFunction f = new UnivariateRealFunction() {<a name="line.214"></a> <FONT color="green">215</FONT> public double value(final double t) throws FunctionEvaluationException {<a name="line.215"></a> <FONT color="green">216</FONT> try {<a name="line.216"></a> <FONT color="green">217</FONT> interpolator.setInterpolatedTime(t);<a name="line.217"></a> <FONT color="green">218</FONT> return handler.g(t, interpolator.getInterpolatedState());<a name="line.218"></a> <FONT color="green">219</FONT> } catch (DerivativeException e) {<a name="line.219"></a> <FONT color="green">220</FONT> throw new FunctionEvaluationException(e, t);<a name="line.220"></a> <FONT color="green">221</FONT> } catch (EventException e) {<a name="line.221"></a> <FONT color="green">222</FONT> throw new FunctionEvaluationException(e, t);<a name="line.222"></a> <FONT color="green">223</FONT> }<a name="line.223"></a> <FONT color="green">224</FONT> }<a name="line.224"></a> <FONT color="green">225</FONT> };<a name="line.225"></a> <FONT color="green">226</FONT> final BrentSolver solver = new BrentSolver();<a name="line.226"></a> <FONT color="green">227</FONT> solver.setAbsoluteAccuracy(convergence);<a name="line.227"></a> <FONT color="green">228</FONT> solver.setMaximalIterationCount(maxIterationCount);<a name="line.228"></a> <FONT color="green">229</FONT> final double root = (ta <= tb) ? solver.solve(f, ta, tb) : solver.solve(f, tb, ta);<a name="line.229"></a> <FONT color="green">230</FONT> if ((Math.abs(root - ta) <= convergence) &&<a name="line.230"></a> <FONT color="green">231</FONT> (Math.abs(root - previousEventTime) <= convergence)) {<a name="line.231"></a> <FONT color="green">232</FONT> // we have either found nothing or found (again ?) a past event, we simply ignore it<a name="line.232"></a> <FONT color="green">233</FONT> ta = tb;<a name="line.233"></a> <FONT color="green">234</FONT> ga = gb;<a name="line.234"></a> <FONT color="green">235</FONT> } else if (Double.isNaN(previousEventTime) ||<a name="line.235"></a> <FONT color="green">236</FONT> (Math.abs(previousEventTime - root) > convergence)) {<a name="line.236"></a> <FONT color="green">237</FONT> pendingEventTime = root;<a name="line.237"></a> <FONT color="green">238</FONT> if (pendingEvent && (Math.abs(t1 - pendingEventTime) <= convergence)) {<a name="line.238"></a> <FONT color="green">239</FONT> // we were already waiting for this event which was<a name="line.239"></a> <FONT color="green">240</FONT> // found during a previous call for a step that was<a name="line.240"></a> <FONT color="green">241</FONT> // rejected, this step must now be accepted since it<a name="line.241"></a> <FONT color="green">242</FONT> // properly ends exactly at the event occurrence<a name="line.242"></a> <FONT color="green">243</FONT> return false;<a name="line.243"></a> <FONT color="green">244</FONT> }<a name="line.244"></a> <FONT color="green">245</FONT> // either we were not waiting for the event or it has<a name="line.245"></a> <FONT color="green">246</FONT> // moved in such a way the step cannot be accepted<a name="line.246"></a> <FONT color="green">247</FONT> pendingEvent = true;<a name="line.247"></a> <FONT color="green">248</FONT> return true;<a name="line.248"></a> <FONT color="green">249</FONT> }<a name="line.249"></a> <FONT color="green">250</FONT> <a name="line.250"></a> <FONT color="green">251</FONT> } else {<a name="line.251"></a> <FONT color="green">252</FONT> // no sign change: there is no event for now<a name="line.252"></a> <FONT color="green">253</FONT> ta = tb;<a name="line.253"></a> <FONT color="green">254</FONT> ga = gb;<a name="line.254"></a> <FONT color="green">255</FONT> }<a name="line.255"></a> <FONT color="green">256</FONT> <a name="line.256"></a> <FONT color="green">257</FONT> }<a name="line.257"></a> <FONT color="green">258</FONT> <a name="line.258"></a> <FONT color="green">259</FONT> // no event during the whole step<a name="line.259"></a> <FONT color="green">260</FONT> pendingEvent = false;<a name="line.260"></a> <FONT color="green">261</FONT> pendingEventTime = Double.NaN;<a name="line.261"></a> <FONT color="green">262</FONT> return false;<a name="line.262"></a> <FONT color="green">263</FONT> <a name="line.263"></a> <FONT color="green">264</FONT> } catch (FunctionEvaluationException e) {<a name="line.264"></a> <FONT color="green">265</FONT> final Throwable cause = e.getCause();<a name="line.265"></a> <FONT color="green">266</FONT> if ((cause != null) && (cause instanceof DerivativeException)) {<a name="line.266"></a> <FONT color="green">267</FONT> throw (DerivativeException) cause;<a name="line.267"></a> <FONT color="green">268</FONT> } else if ((cause != null) && (cause instanceof EventException)) {<a name="line.268"></a> <FONT color="green">269</FONT> throw (EventException) cause;<a name="line.269"></a> <FONT color="green">270</FONT> }<a name="line.270"></a> <FONT color="green">271</FONT> throw new EventException(e);<a name="line.271"></a> <FONT color="green">272</FONT> }<a name="line.272"></a> <FONT color="green">273</FONT> <a name="line.273"></a> <FONT color="green">274</FONT> }<a name="line.274"></a> <FONT color="green">275</FONT> <a name="line.275"></a> <FONT color="green">276</FONT> /** Get the occurrence time of the event triggered in the current<a name="line.276"></a> <FONT color="green">277</FONT> * step.<a name="line.277"></a> <FONT color="green">278</FONT> * @return occurrence time of the event triggered in the current<a name="line.278"></a> <FONT color="green">279</FONT> * step.<a name="line.279"></a> <FONT color="green">280</FONT> */<a name="line.280"></a> <FONT color="green">281</FONT> public double getEventTime() {<a name="line.281"></a> <FONT color="green">282</FONT> return pendingEventTime;<a name="line.282"></a> <FONT color="green">283</FONT> }<a name="line.283"></a> <FONT color="green">284</FONT> <a name="line.284"></a> <FONT color="green">285</FONT> /** Acknowledge the fact the step has been accepted by the integrator.<a name="line.285"></a> <FONT color="green">286</FONT> * @param t value of the independent <i>time</i> variable at the<a name="line.286"></a> <FONT color="green">287</FONT> * end of the step<a name="line.287"></a> <FONT color="green">288</FONT> * @param y array containing the current value of the state vector<a name="line.288"></a> <FONT color="green">289</FONT> * at the end of the step<a name="line.289"></a> <FONT color="green">290</FONT> * @exception EventException if the value of the event<a name="line.290"></a> <FONT color="green">291</FONT> * handler cannot be evaluated<a name="line.291"></a> <FONT color="green">292</FONT> */<a name="line.292"></a> <FONT color="green">293</FONT> public void stepAccepted(final double t, final double[] y)<a name="line.293"></a> <FONT color="green">294</FONT> throws EventException {<a name="line.294"></a> <FONT color="green">295</FONT> <a name="line.295"></a> <FONT color="green">296</FONT> t0 = t;<a name="line.296"></a> <FONT color="green">297</FONT> g0 = handler.g(t, y);<a name="line.297"></a> <FONT color="green">298</FONT> <a name="line.298"></a> <FONT color="green">299</FONT> if (pendingEvent) {<a name="line.299"></a> <FONT color="green">300</FONT> // force the sign to its value "just after the event"<a name="line.300"></a> <FONT color="green">301</FONT> previousEventTime = t;<a name="line.301"></a> <FONT color="green">302</FONT> g0Positive = increasing;<a name="line.302"></a> <FONT color="green">303</FONT> nextAction = handler.eventOccurred(t, y, !(increasing ^ forward));<a name="line.303"></a> <FONT color="green">304</FONT> } else {<a name="line.304"></a> <FONT color="green">305</FONT> g0Positive = g0 >= 0;<a name="line.305"></a> <FONT color="green">306</FONT> nextAction = EventHandler.CONTINUE;<a name="line.306"></a> <FONT color="green">307</FONT> }<a name="line.307"></a> <FONT color="green">308</FONT> }<a name="line.308"></a> <FONT color="green">309</FONT> <a name="line.309"></a> <FONT color="green">310</FONT> /** Check if the integration should be stopped at the end of the<a name="line.310"></a> <FONT color="green">311</FONT> * current step.<a name="line.311"></a> <FONT color="green">312</FONT> * @return true if the integration should be stopped<a name="line.312"></a> <FONT color="green">313</FONT> */<a name="line.313"></a> <FONT color="green">314</FONT> public boolean stop() {<a name="line.314"></a> <FONT color="green">315</FONT> return nextAction == EventHandler.STOP;<a name="line.315"></a> <FONT color="green">316</FONT> }<a name="line.316"></a> <FONT color="green">317</FONT> <a name="line.317"></a> <FONT color="green">318</FONT> /** Let the event handler reset the state if it wants.<a name="line.318"></a> <FONT color="green">319</FONT> * @param t value of the independent <i>time</i> variable at the<a name="line.319"></a> <FONT color="green">320</FONT> * beginning of the next step<a name="line.320"></a> <FONT color="green">321</FONT> * @param y array were to put the desired state vector at the beginning<a name="line.321"></a> <FONT color="green">322</FONT> * of the next step<a name="line.322"></a> <FONT color="green">323</FONT> * @return true if the integrator should reset the derivatives too<a name="line.323"></a> <FONT color="green">324</FONT> * @exception EventException if the state cannot be reseted by the event<a name="line.324"></a> <FONT color="green">325</FONT> * handler<a name="line.325"></a> <FONT color="green">326</FONT> */<a name="line.326"></a> <FONT color="green">327</FONT> public boolean reset(final double t, final double[] y)<a name="line.327"></a> <FONT color="green">328</FONT> throws EventException {<a name="line.328"></a> <FONT color="green">329</FONT> <a name="line.329"></a> <FONT color="green">330</FONT> if (! pendingEvent) {<a name="line.330"></a> <FONT color="green">331</FONT> return false;<a name="line.331"></a> <FONT color="green">332</FONT> }<a name="line.332"></a> <FONT color="green">333</FONT> <a name="line.333"></a> <FONT color="green">334</FONT> if (nextAction == EventHandler.RESET_STATE) {<a name="line.334"></a> <FONT color="green">335</FONT> handler.resetState(t, y);<a name="line.335"></a> <FONT color="green">336</FONT> }<a name="line.336"></a> <FONT color="green">337</FONT> pendingEvent = false;<a name="line.337"></a> <FONT color="green">338</FONT> pendingEventTime = Double.NaN;<a name="line.338"></a> <FONT color="green">339</FONT> <a name="line.339"></a> <FONT color="green">340</FONT> return (nextAction == EventHandler.RESET_STATE) ||<a name="line.340"></a> <FONT color="green">341</FONT> (nextAction == EventHandler.RESET_DERIVATIVES);<a name="line.341"></a> <FONT color="green">342</FONT> <a name="line.342"></a> <FONT color="green">343</FONT> }<a name="line.343"></a> <FONT color="green">344</FONT> <a name="line.344"></a> <FONT color="green">345</FONT> }<a name="line.345"></a> </PRE> </BODY> </HTML>