150 lines
7.6 KiB
HTML
150 lines
7.6 KiB
HTML
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta name="GENERATOR" content="Mozilla/4.73 [en] (X11; I; Linux 2.2.15-4mdk i686) [Netscape]">
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<title>Variation Operators</title>
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</head>
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<body text="#000000" link="#0000EF" vlink="#51188E" alink="#FF0000" background="beige009.jpg">
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<b><font color="#FF0000">General</font></b>: <a href="eoTopDown.html">Algorithm-Based</a>
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- <a href="eoBottomUp.html">Component-Based</a> - <a href="eoProgramming.html">Programming
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hints</a> - <b><font face="Arial,Helvetica"><font size=+1><a href="../../doc/html/index.html">EO
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documentation</a></font></font></b>
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<br>
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<hr WIDTH="100%">
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<br><b><font color="#FF0000">Local</font></b>: <a href="#introduction">Introduction</a>
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- <a href="#continuator">Continuators</a> - <a href="#combined_continue">Combined
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continuators</a> - <a href="#checkpoint">Checkpoints</a> - <a href="#statistic">Statistics</a>
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- <a href="#monitor">Monitors</a> - <a href="#updater">Updaters</a>
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<br>
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<hr WIDTH="100%">
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<center>
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<h1>
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<b><font color="#CC0000">CheckPointing</font></b></h1></center>
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<a NAME="introduction"></a><b><font color="#000099"><font size=+2>What
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is Checkpointing about?</font></font></b>
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<br>Evolutionary Algorithms are almost all timely ticked, the basic time
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unit being what is called a generation. EO checkpointing mechanism allow
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you to program things that you want to be done at the end of every generation.
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This includes deciding to stop, outputing some statistics on the current
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state of the algorithm, updating some dynamical variables of your
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algorithm, saving the population to disk, ...
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<p><b><font color="#FF0000">EO classes described in this page</font></b>:
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<ul>
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<li>
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<b><font color="#FF0000">Base classes</font></b>: eoCheckPoint, <a href="#continuator">eoContinue</a>,
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eoStat, eoSortedStat, eoMonitor, eoUpdater</li>
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<li>
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<b><font color="#FF0000">Derived classes</font></b>: eoCombinedContinue,</li>
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<li>
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<b><font color="#FF0000">Related classes</font></b>: eoGnuPlot1DMonitor,
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eoGnuPlot1DSnapshotMonitor,</li>
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</ul>
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<br>
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<p>
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<hr WIDTH="100%"><a NAME="continuator"></a><b><font color="#000099"><font size=+1>Continuators:</font></font></b>
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<p>Continuators are functors that compute stopping critera. They receive
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a population and return a boolean value which is set to false only when
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some stopping vriterion is met. All algorithms in EO have a loop that goes
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<b><font color="#993300">do{...}while(continuator(pop)</font></b>which
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means that the algorithm stops only when the continuator returns <b><font color="#993300">false</font></b>.
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<p><b><font color="#FF0000">Interface</font></b>: The abstract class
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for computing stopping conditions is <b><font color="#3366FF">eoContinue</font></b>,
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and the interface for its operator() is
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<p>
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<b><tt><font color="#993300"><font size=+1>bool operator()(const eoPop<EOT>&
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)</font></font></tt></b>
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<p>which you could have guessed from the <a href="../../doc/html/classeo_continue.html">inheritance
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diagram</a> for class <b><font color="#3366FF">eoContinue</font></b>, as
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you see there that <b><font color="#3366FF">eoContinue</font></b> derives
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from class <b><tt><font color="#993300"><font size=+1>eoUF<const eoPop<EOT>&,
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bool></font></font></tt></b>.
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<p><b><font color="#FF0000">Using a continuator</font></b>:
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<br>You can find an first example of using a continuator in the code for
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<a href="FirstBitGA.html#stop">FirstBitEA</a>
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ior more sophisticated continue conditions in <a href="eoLesson2.html#combinedContinue">Lesson2</a>.
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<br>If you want to find out how it is used inside an algorithm, go and
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see for instance in eoSGA, the simplest EA within EO.
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<p><a NAME="writing_continuator"></a><b><font color="#FF0000">Writing a
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continuator:</font></b>
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<br>There are only two things to modify in the <a href="../Templates/continue.tmpl">template
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class definitions</a> provided (apart from the name of the class you are
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creating!)
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<ul>
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<li>
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The <font color="#FF6600">constructor</font>, where you pass to the object
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any useful parameter (see the private data at end of class definition).</li>
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<li>
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The <font color="#FF6600">operator()</font> method, which performs the
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computation of the actual test using the population plus any other parameter
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passed at construct time. Don't forget to <b><font color="#FF6600">returnfalse</font></b>
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when the stopping criterion <b><font color="#FF6600">is met!</font></b></li>
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</ul>
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<a NAME="existingContinue"></a><b><font color="#FF0000">Existing continuators:
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</font></b>Of
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course you can find out all existing (non-virtual!) subclasses of eoContinue
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by looking at its <a href="../../doc/html/classeo_continue.html">inheritance
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diagram</a>. But you might find it more convenient to have them listed
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here:
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<ul>
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<li>
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</li>
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</ul>
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<p><br>
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<hr WIDTH="100%"><a NAME="combined_continue"></a><b><font color="#000099"><font size=+1>Combining
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continuators:</font></font></b>
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<p>
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<hr WIDTH="100%"><a NAME="checkpoint"></a><b><font color="#000099"><font size=+1>CheckPoints:</font></font></b>
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<p><b><font color="#FF0000">Interface</font></b>:
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<p><b><font color="#FF0000">Using a checkpoint</font></b>: An eoCheckPoint
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being an eoContinue, its usage is exactly the same. However, an eoCheckPoint
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will actually do many more things than an eoContinue before returning its
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boolean result as an eoContinue.
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<p><a NAME="writing_checkpoint"></a><b><font color="#FF0000">Writing a
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checkpoint:</font></b>
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<br>This is something you should never have to do. However, should you
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feel you have to do it, please do - and send us both the reasons that lead
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you to that (what is it you couldn't do with existing eoCheckPoint), and
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the resulting code, of course.
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<br>
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<hr WIDTH="100%"><a NAME="statistic"></a><b><font color="#000099"><font size=+1>Statistics:</font></font></b>
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<p><b><font color="#FF0000">Interface</font></b>:
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<p><b><font color="#FF0000">Using statistics</font></b>:
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<p><a NAME="writing_statistic"></a><b><font color="#FF0000">Writing a statitic</font></b>:
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<br>
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<hr WIDTH="100%"><a NAME="monitor"></a><b><font color="#000099"><font size=+1>Monitors:</font></font></b>
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<p><b><font color="#FF0000">Interface</font></b>:
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<p><b><font color="#FF0000">Using monitors</font></b>:
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<p><a NAME="writing_monitor"></a><b><font color="#FF0000">Writing a monitor</font></b>:
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<p>
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<hr WIDTH="100%"><a NAME="updater"></a><b><font color="#000099"><font size=+1>Updater:</font></font></b>
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<p><b><font color="#FF0000">Interface</font></b>:
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<p><b><font color="#FF0000">Using updaters</font></b>:
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<p><a NAME="writing_updater"></a><b><font color="#FF0000">Writing an updater</font></b>:
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<br>
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<p>
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<hr WIDTH="100%"><b><font color="#FF0000">Local</font></b>: <a href="#introduction">Introduction</a>
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- <a href="#continuator">Continuators</a> - <a href="#combined_continue">Combined
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continuators</a> - <a href="#checkpoint">Checkpoints</a> - <a href="#statistic">Statistics</a>
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- <a href="#monitor">Monitors</a> - <a href="#updater">Updaters</a>
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<br>
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<hr WIDTH="100%"><b><font color="#FF0000">General</font></b>: <a href="eoTopDown.html">Algorithm-Based</a>
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- <a href="eoBottomUp.html">Component-Based</a> - <a href="eoProgramming.html">Programming
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hints</a> -<b><font face="Arial,Helvetica"><font size=+1><a href="../../doc/html/index.html">EO
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documentation</a></font></font></b>
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<br>
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<hr>
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<address>
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<a href="mailto:Marc.Schoenauer@inria.fr">Marc Schoenauer</a></address>
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<br><!-- Created: Mon Oct 30 07:27:13 CET 2000 --><!-- hhmts start -->Last
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modified: Fri Dec. 8 2000 <!-- hhmts end -->
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<br>
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</body>
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</html>
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