Hi Michael,<br><br>The java code can be downloaded from:<br><a href="http://sourceforge.net/projects/java-galib/">http://sourceforge.net/projects/java-galib/</a><br><br>Best Regards,<br>Zyed<br><br><br><div class="gmail_quote">
On Tue, Mar 17, 2009 at 9:29 PM, Kupfer, Michael (ARC-TH)[San Jose State University Foundation] <span dir="ltr"><<a href="mailto:michael.kupfer@nasa.gov">michael.kupfer@nasa.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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<p><span style="font-size: 11pt; color: rgb(31, 73, 125);">Hello Zyed!</span></p>
<p><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p><span style="font-size: 11pt; color: rgb(31, 73, 125);">I read you’re using the Java version of GAlib? Where did you get
it from? Is it an exact representation of the C++ version (could I translate my
C++ code 1-1 into Java)?</span></p>
<p><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p><span style="font-size: 11pt; color: rgb(31, 73, 125);">Best,</span></p>
<p><span style="font-size: 11pt; color: rgb(31, 73, 125);">Michael.</span></p>
<p><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
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<p><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;">
<a href="mailto:galib-bounces@mit.edu" target="_blank">galib-bounces@mit.edu</a> [mailto:<a href="mailto:galib-bounces@mit.edu" target="_blank">galib-bounces@mit.edu</a>] <b>On Behalf Of </b>Zyed
Bouzarkouna<br>
<b>Sent:</b> Tuesday, March 17, 2009 9:13 AM<br>
<b>To:</b> <a href="mailto:galib@mit.edu" target="_blank">galib@mit.edu</a><br>
<b>Subject:</b> Re: [galib] Ellitism</span></p>
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<p style="margin-bottom: 12pt;">Thanks Robert for your reply.<br>
In fact, I'm using The java version of GALib. <br>
<br>
//Elitism--fittest chromosome
automatically go on to next gen (in 2 offspring)<br>
<br>
this.chromNextGen[iCnt].copyChromGenes(this.chromosomes[this.bestFitnessChromIndex]);<br>
iCnt++;<br>
<br>
this.chromNextGen[iCnt].copyChromGenes(this.chromosomes[this.bestFitnessChromIndex]);<br>
iCnt++;<br>
<br>
And here I don't see any reason to put it twice especially since we don't allow
any mutation on the best indiv.<br>
<br>
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<p>On Tue, Mar 17, 2009 at 4:56 PM, Robert Burbidge <<a href="mailto:rvb@aber.ac.uk" target="_blank">rvb@aber.ac.uk</a>> wrote:</p>
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<p style="margin-bottom: 12pt;">On 17 Mar 2009, at 15:35, Zyed
Bouzarkouna wrote:</p>
<p>I was wondering why to apply elitism, GALib choooses the
fittest chromosome to go automatically to next gen in 2 offspring.<br>
I don't see why the fittest is put twice in the next generation?</p>
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<p>Hi Zyed,<br>
<br>
I assume you are using a simple GA as elitism doesn't make sense for a steady
state or incremental GA. The relevant code snippet is:<br>
<br>
>>>>>>>><br>
void<br>
GASimpleGA::step()<br>
{<br>
...<br>
// If we are supposed to be elitist, carry the best individual from the old<br>
// population into the current population. Be sure to check whether we are<br>
// supposed to minimize or maximize.<br>
<br>
if(minimaxi() == GAGeneticAlgorithm::MAXIMIZE) {<br>
if(el && oldPop->best().score() >
pop->best().score())<br>
oldPop->replace(pop->replace(&(oldPop->best()),
GAPopulation::WORST),<br>
GAPopulation::BEST);<br>
}<br>
else {<br>
if(el && oldPop->best().score() <
pop->best().score())<br>
oldPop->replace(pop->replace(&(oldPop->best()),
GAPopulation::WORST),<br>
GAPopulation::BEST);<br>
}<br>
...<br>
}<br>
<<<<<<<<<<<br>
<br>
We can see that the best individual from the old population replaces the worst
individual in the current population, provided that it is better than the best
individual in the current population. This only results in one copy of the best
in the current population.<br>
<br>
It is of course possible to obtain more than one copy of the best through
selection if it happens that it is not crossed over or mutated. Try running
with pcross = 1.0 and you should only see (at most) one copy of the best in the
next generation with elitism (except for the hopefully rare case where the
crossover has no effect).<br>
<br>
Rgds,<br>
<span style="color: rgb(136, 136, 136);">Robert</span></p>
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<br clear="all">
<br>
-- <br>
Zyed Bouzarkouna<br>
<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Zyed Bouzarkouna<br> <br> <br>