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<ul>
<li>
go to marked position</li>

<li>
until <a href="#container_and_populator">current end of population</a>
is reached do</li>

<ul>
<li>
flip a coin according to the operator rate.</li>

<ul>
<li>
If true, apply the operator to the parents. The current parents can be
modified, or some can be deleted from the list, or some offspring can be
inserted in the list.</li>

<li>
If false, move the pointer over the required number of parents (i.e. don't
modify thoses parents)</li>
</ul>

<li>
Next pending parent</li>
</ul>

<li>
Next operator</li>
</ul>
<b><font color="#FF6600">Warning</font></b>: the way <b><tt><font color="#993300">rate</font></tt></b>
will be used is highly dependent on the type of <b><font color="#CC33CC">eoOpContainer</font></b>
your are creating there:
<ul>
<li>
The rates for <b><font color="#CC33CC">eoProportionalOpContainer</font></b>
will be used in a roulette wheel choice among all operators. They can take
any value, the only important thing is their <b><font color="#FF6600">relative
values</font></b>.</li>

<li>
The "rates" for <b><font color="#CC33CC">eoSequentialOpContainer </font></b>actually
are <b><font color="#FF6600">probabilities</font></b>, i.e. they will be
used in a coin-flipping to determine whether that particuler operator will
be applied to the next candidates at hand. They should be <b><font color="#FF6600">in
[0,1]</font></b> (no error will happen if they are not, but the operator
will be applied systematically - this is equivalent of a rate equal to
1).</li>
</ul>
<font color="#FF6600">Remark:</font>The eoSGATransform presented in <a href="eoLesson2.html#transform">Lesson2</a>
can be viewed as a particular type of <b><font color="#CC33CC">eoSequentialOpContainer</font></b>.
It was not coded that way in order to provide a gradual introduction to
all concepts.
<br><font color="#FF6600">Exercise</font>: write the code to perform an
eoSGA using the eoOpContainer constructs.
<p><b><font color="#FF0000">Adding operators to a container:</font></b>
<br>The way to add an operator to an <b><font color="#CC33CC">eoOpContainer</font></b>
is the method
<b><tt><font color="#993300">add</font></tt></b>. It is similar
to all other <b><tt><font color="#993300">add</font></tt></b> methods in
other Combined things in eo (as the simple eoProportionalCombinedXXXop
described above, but also the eoCombinedContinue class or the eoCheckPoint
class).
<br>The syntax is straightforward, and it works with any of the operator
classes <b><font color="#CC33CC">eoXXXOp</font></b>, where XXX stands for
<b><font color="#CC33CC">Mon,
Bin, Quad </font></b><font color="#000000">or</font><b><font color="#CC33CC">
Gen</font></b>:
<p><b><tt><font color="#993300">someOperatorType&lt;Indi> myOperator;</font></tt></b>
<br><b><tt><font color="#993300">eoYYYOpContainer&lt;Indi> myOpContainer;</font></tt></b>
<br><tt><font color="#993300"><b>myOpContainer.add(myOperator, rate); </b>//
rate: double whose <b>meaning depends on YYY</b></font></tt>
<p>where YYY can be one of Proportional and Sequential. Note that before
being added to the container, all simple operators are wrapped into the
corresponding eoGenOp (see e.g. how an <b><font color="#CC33CC">eoMonOp</font></b><a href="../../doc/html/eo_gen_op_8h-source.html#l00084">is
wrapped</a> into an <b><font color="#CC33CC">eoMonGenOp</font></b>- or
how <a href="../../doc/html/eo_gen_op_8h-source.html#l00169">any operator
is handled</a> by calling the appropriate wrapper). In particular, the
wrapper ensures that <b><font color="#FF6600">individuals who have been
modified are invalidated</font></b>.
<p><a NAME="container_and_populator"></a><b><font color="#FF0000">Containers,
Selectors and Populators</font></b>
<br>The way the <b><font color="#CC33CC">eoOpContainer</font></b> are applied
on a population using an <b><font color="#999900">eoPopulator</font></b>
object. But, whereas the behavior of <b><font color="#CC33CC"><a href="#prop_container">eoProportionalOpContainer</a></font></b>
does not depend on the type of <b><font color="#999900">eoPopulator</font></b>,(one
operator is chosen by roulette_wheel, and applied once before control is
given back to the caller), the main loop in method <b><tt><font color="#993300">operator()
</font></tt></b>of
class <b><font color="#CC33CC"><a href="#seqential_container">eoSequentialOpContainer</a></font></b>
iterates <b><tt><font color="#993300">while (!_pop.exhausted())</font></tt></b>
which is interpreted differently depending on the <a href="#populators">type
of <b><font color="#CC33CC">eoPopulator</font></b></a>:
<ul>
<li>
if the argument is an <b><font color="#999900">eoSelectivePopulator</font></b>,
the default position of the eoPopulator, considered as a population iterator,
is at end of population. Individuals are added upon demand of an operator,
and in most cases all operators are applied once. This also depends, however,
on the arities of all operators:</li>

<ul>
<li>
Consider an <b><font color="#CC33CC">eoSequentialOpContainer</font></b>
containing an eoQuadOp and an eoMonOp. The eoQuadOp first asks for two
parents and modifies them. The eoMonOp is then called starting from the
forst of thoses two modified individuals, and is hence applied twice, once
on each parent.</li>

<li>
But consider now an <b><font color="#CC33CC">eoSequentialOpContainer</font></b>
containing an <b><font color="#CC33CC">eoGenOp</font></b> that takes one
parent and generates three offspring, followed by an <b><font color="#CC33CC">eoQuadOp</font></b>.
The <b><font color="#CC33CC">eoGenOp</font></b> will call the selector
to get the parent its need and will modify it and put 2 additional offspring
at end of the population. The <b><font color="#CC33CC">eoQuadOp</font></b>
will then be called on the first of the three outputs of the <b><font color="#CC33CC">eoGenOp</font></b>,
and hence will act upon the frist two of them. But at that point, the populator
iterator will point to the third of the individuals resulting from the
<b><font color="#CC33CC">eoGenOp</font></b>,
and the test <b><tt><font color="#993300">_pop.exhausted()</font></tt></b>
will return false, so the <b><font color="#CC33CC">eoQuadOp</font></b>
will again be called. The second parent it needs will be given by a new
call to the embedded <b><font color="#009900">eoSelectOne</font></b> of
the&nbsp; and everything will go on smoothly, except that a total of 4
offspring will have been generated by application of this particular <b><font color="#CC33CC">eoSequentialOpContainer</font></b>.</li>
</ul>

<li>
if the argument is an <b><font color="#999900">eoSeqPopulator</font></b>,
the position of the iterator starts from the beginning of an existing population
(the source populations), and hence when an&nbsp; an <b><font color="#CC33CC">eoSequentialOpContainer</font></b>
is called, it goes through the whole remaining of the population (the test
<b><tt><font color="#993300">_pop.exhausted()</font></tt></b>
only returns true at end of the source population).</li>

<li>
From the above it is easy to see that passing an <b><font color="#999900">eoSeqPopulator</font></b>
to an <b><font color="#CC33CC">eoProportionalOpContainer</font></b> that
contains an <b><font color="#CC33CC">eoSequentialOpContainer</font></b>,
though not technically forbiddden, will most produce something&nbsp; totally
unpredictable, and hence should probably not be used without great care.</li>
</ul>

<hr WIDTH="100%"><a NAME="advanced_general"></a><b><font color="#000099"><font size=+2>Advanced
general operators:</font></font></b>
<p>It is sometimes useful to be able to use a selector from inside an operator
(a typical example is when you want to implement <b><font color="#FF6600">sexual
preferences</font></b>, i.e. choose a mate for a first parent according
to some characteritics of that first parent).
<br>This is made possible in EO because the general operators have a handle
on the initial population through the method <b><tt><font color="#993300">source()</font></tt></b>
of the argument eoPopulator they work on. Their <b><tt><font color="#993300">apply()</font></tt></b>
method shoudl look like
<p><b><tt><font color="#993300">void apply()(</font><font color="#999900">eoPopulator</font><font color="#993300">&amp;
_pop)</font></tt></b>
<br><b><tt><font color="#993300">{</font></tt></b>
<br><tt><font color="#993300"><b>&nbsp; EOT &amp; eo1 = *_pop; </b>// get
(select if necessary) the first guy</font></tt>
<br><b><tt><font color="#993300">&nbsp; EOT maBlonde = </font><font color="#009900">findBlonde</font><font color="#993300">(_pop.source());
</font></tt></b><tt><font color="#993300">//
select mate</font></tt>
<br><tt><font color="#993300">&nbsp; // do whatever the operator is supposed
to do, e.g</font></tt>
<br><tt><font color="#993300">&nbsp; <b>cross(eo1, maBonde);</b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
// cross is some embedded crossover</font></tt>
<br><tt><font color="#993300">&nbsp; <b>...</b></font></tt>
<br><tt><font color="#993300">&nbsp; // if you don't want to put maBlonde
into the offspring,</font></tt>
<br><tt><font color="#993300">&nbsp; // stop here (and use a reference
to maBlonde above). Otherwise</font></tt>
<br><tt><font color="#993300">&nbsp; <b>maBonde.invalidate();</b></font></tt>
<br><tt><font color="#993300"><b>&nbsp;++_pop;&nbsp;&nbsp;&nbsp; </b>//
advance</font></tt>
<br><tt><font color="#993300">&nbsp; <b>_pop.insert(maBlonde);</b>&nbsp;&nbsp;&nbsp;
// and insert it</font></tt>
<br><b><tt><font color="#993300">}</font></tt></b>
<p>Where does that <b><tt><font color="#009900">findBlonde</font></tt></b>
selector comes from? As usual, you have to attach it to the operator,&nbsp;
in its constructor for instance, which should give something like:
<p><b><tt><font color="#993300">sexualSelectorType&lt;Indi>&nbsp; findBlonde;</font></tt></b>
<br><b><tt><font color="#993300">sexualOperatorType&lt;Indi> yourBrainAndMyBeauty(cross,
findBlonde);</font></tt></b>
<p>
<hr WIDTH="100%"><b><font color="#FF0000">Local</font></b>: <a href="#introduction">Introduction</a>
- <a href="#crossover">Crossover</a> - <a href="#mutation">Mutation</a>
- <a href="#proportional_simple">Combinations</a> - <a href="#general">General
Operators</a> - <a href="#populators">Populators</a> - <a href="#general_combination">General
combinations</a>- <a href="#advanced_general">Advanced operators
<hr WIDTH="100%"></a><b><font color="#FF0000">General</font></b>: <a href="eoTopDown.html">Algorithm-Based</a>
- <a href="eoBottomUp.html">Component-Based</a> - <a href="eoProgramming.html">Programming
hints</a> -<b><font face="Arial,Helvetica"><font size=+1><a href="../../doc/html/index.html">EO
documentation</a></font></font></b>
<br>
<hr>
<address>
<a href="mailto:[e-mail]">Marc Schoenauer</a></address>

<br><!-- Created: Mon Oct 30 07:27:13 CET 2000 --><!-- hhmts start -->Last
modified: Sat. Feb. 17 2002&nbsp;<!-- hhmts end -->
<br>&nbsp;
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