2a93bba7e6
Also added all replacement procedures in eoEngine.html and the general operator interface in eoOperators.html
256 lines
13 KiB
HTML
256 lines
13 KiB
HTML
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
|
<meta name="GENERATOR" content="Mozilla/4.75 [en] (X11; U; Linux 2.2.17-21mdksmp i686) [Netscape]">
|
|
<title>EO Programming guide</title>
|
|
</head>
|
|
<body text="#000000" link="#0000EE" vlink="#551A8B" alink="#FF0000" background="beige009.jpg">
|
|
<a href="eoTutorial.html">Tutorial main page </a>-
|
|
<a href="eoTopDown.html">Algorithm-Based
|
|
page</a> - <a href="eoBottomUp.html">Component-Based</a> - <a href="eoProgramming.html">Programming
|
|
hints</a> - <font face="Arial,Helvetica"><a href="../../doc/html/index.html">EO
|
|
documentation</a></font>
|
|
<br>
|
|
<hr WIDTH="100%"><!-- -------------- End of header ------------------ --><!-- ----------------------------------------------- -->
|
|
<center>
|
|
<h1>
|
|
<font color="#FF0000">EO Programming guide</font></h1></center>
|
|
<!-- ----------------------------------------------- --><a href="#templates">Templates</a>,
|
|
<a href="#functors">Functors</a>,
|
|
<a href="#STL">STL
|
|
Library</a>, random numbers, <a href="#notations">EO programming style</a>!
|
|
<br>
|
|
<hr WIDTH="100%">
|
|
<br><a NAME="templates"></a><b><font color="#000099"><font size=+1>Templates</font></font></b>
|
|
<br>Most EO code is written using templates. This allows to write generic
|
|
code, i.e. involving a class which doesn't have to be known when writing
|
|
the code -- but only when compiling it. In some sense this is similar to
|
|
naming variables in algebra: you can write a lot of equations involving
|
|
some variable $x$ without knowing even it if will be an integer or a float
|
|
(or a matrix or ...). The main basic type that is templatized in EO is
|
|
the fitness: an EO object is some object which has a fitness of some type
|
|
F that can be anything. The definition for that is (see<font face="Arial,Helvetica"><a href="doc/EO.h-source.html">EO.h</a></font>)
|
|
<p><b><tt><font color="#999900"><font size=+1>template<F> class EO</font></font></tt></b>
|
|
<p>The idea is that, later in your code, you can declare for instance as
|
|
in <a href="FirstBitGA.html#representation">FirstBitGA.cpp</a>
|
|
<p><b><tt><font color="#999900"><font size=+1>typedef eoBin<double>
|
|
Genotype;</font></font></tt></b>
|
|
<p>meaning that in that file, you will manipulate as <b><tt><font color="#999900"><font size=+1>Genotype</font></font></tt></b>
|
|
objects that are EO objects <font color="#000000">whose</font><b><font color="#FF6600">fitness</font></b><font color="#000000">
|
|
is a </font><font color="#FF6600"><b>double</b>.</font>
|
|
<p>Whereas the advantages are obvious (writing generic reusable code instead
|
|
of having to rewrite the same pieces of code for different types), there
|
|
are some drawbacks: namely, it makes some of the compiler error messages
|
|
hard to understand; and it forbids the compilation of most parts of EO
|
|
into an object library file, as the actual types are not known in advance.
|
|
<p>
|
|
<hr WIDTH="100%">
|
|
<br><a NAME="functors"></a><b><font color="#000099"><font size=+1>Functors</font></font></b>
|
|
<p>Though EO is a library, it contains almost no functions!
|
|
<br>EO only contains functors, that are objects which have a method called
|
|
<b><tt><font color="#FF6600"><font size=+1>operator()</font></font></tt></b>.
|
|
Such objects are used as if they were a function, but the big differences
|
|
are that
|
|
<ul>
|
|
<li>
|
|
functors are functions with private data</li>
|
|
|
|
<li>
|
|
you can have different functors objects of the same class, i.e. you can
|
|
use the same functionality with different parameters</li>
|
|
|
|
<li>
|
|
you can heave a hierarchy of functors objects, which means that you have
|
|
a hierarchy of functions with defaults behaviors and specialized sub-functions</li>
|
|
|
|
<li>
|
|
...</li>
|
|
</ul>
|
|
Functors are so intimately linked to EO that a base class (<a href="../../doc/html/class_eofunctorbase.html">eoFunctorBase</a>)
|
|
has been designed to hold all functors. This base class is itself divided
|
|
into three derived class. These classes tell you immediately what kind
|
|
of arguments the <font color="#993300">operator()</font> method requires
|
|
and what kind of result it produces. See <a href="#notations">EO conventions</a>,
|
|
and
|
|
the <a href="doc/class_eofunctorbase.html">inheritance diagram of class
|
|
eoFunctorBase</a>.
|
|
<p><b><font color="#000099">Example</font></b>
|
|
<p>A good example is given by the <tt><font color="#990000"><font size=+1>eoEvalFuncPtr</font></font></tt>
|
|
class
|
|
<p><tt><font color="#993300">class MyClass</font></tt>
|
|
<br><tt><font color="#993300">{ ...</font></tt>
|
|
<br><tt><font color="#993300"> void operator()(ArgType
|
|
arg)</font></tt>
|
|
<br><tt><font color="#993300"> {</font></tt>
|
|
<br><tt><font color="#993300">
|
|
// do what you have to do</font></tt>
|
|
<br><tt><font color="#993300"> }</font></tt>
|
|
<br><tt><font color="#993300">}; // end of class declaration</font></tt>
|
|
<p>is used later in the code in something like
|
|
<br>
|
|
<p><tt><font color="#993300">ArgType myArgument;</font></tt>
|
|
<br><tt><font color="#993300">MyClass myObject; // myObject
|
|
is an object of class MyClass ...</font></tt>
|
|
<br><tt><font color="#993300">myObject(myArgument); // calls method
|
|
operator() of object myObject with argument myArgument ...</font></tt>
|
|
<br>
|
|
<br>
|
|
<br>
|
|
<h2>
|
|
Why not plain C functions?</h2>
|
|
Consider for instance variation operators. Of course, we could declare
|
|
them as function acting on some objects.
|
|
<p><tt>Blabla</tt>
|
|
<p>
|
|
<hr WIDTH="100%">
|
|
<br><a NAME="STL"></a><b><font color="#000099"><font size=+1>A very brief
|
|
introduction to STL</font></font></b>
|
|
<p>All EO heavily relies on <b><font color="#FF6600">STL, the Standard
|
|
Template Library</font></b>.
|
|
<br>But <font color="#FF6600">you don't have to know more than a few words
|
|
of STL</font> to use EO (like with "hello", "please" and "goodbye" you
|
|
can survive in a foreign country :-) and even to contribute to new EO features.
|
|
<p>You will only find here the basics of STL that you will need to understand
|
|
most of EO code - and to guess what the parts you don't understand are
|
|
actually doing. Don't worry, <b><font color="#FF6600">I </font></b>don't
|
|
understand everything :-)
|
|
<p>STL provides the user with <b><font color="#FF6600">container</font></b>
|
|
and <b><font color="#FF6600">algorithms</font></b>. And you can apply (almost)
|
|
all algorithms on (almost) all containers.
|
|
<p><b><font color="#000099">Containers</font></b>
|
|
<br>Containers are high level data types used to hold simpler data - the
|
|
most widely used example of a container is the <b><font color="#FF6600">vector</font></b>
|
|
construct.
|
|
<br>The use of STL containers relieve the user from memory management.
|
|
<ul>
|
|
<li>
|
|
<b><tt><font color="#000099"><font size=+1>vector </font></font></tt></b><font color="#000000">The
|
|
most widely used container is a one-dimensional array of items.</font></li>
|
|
|
|
<br><font color="#000000">Data manipulation: suppose </font><font color="#FF6600">v
|
|
is an STL </font><tt><font color="#993300"><font size=+1>vector<AtomType></font></font></tt><font color="#000000">.
|
|
Then</font>
|
|
<br><tt><font color="#993300"><font size=+1>v[i]</font></font></tt><font color="#000000">
|
|
is the ith element of v, as in standard C arrays</font>
|
|
<br><tt><font color="#993300"><font size=+1>v.size()</font></font></tt><font color="#000000">
|
|
is the number of elements of v</font>
|
|
<br><tt><font color="#993300"><font size=+1>v.push_back(atom)</font></font></tt><font color="#000000">
|
|
appends the </font><tt><font color="#993300"><font size=+1>atom</font></font></tt><font color="#000000">
|
|
at end of </font><tt><font color="#993300"><font size=+1>v</font></font></tt><font color="#000000">,
|
|
provided of course that </font><tt><font color="#993300"><font size=+1>atom</font></font></tt><font color="#000000">
|
|
is of type </font><tt><font color="#993300"><font size=+1>AtomType</font></font></tt>
|
|
<br><font color="#000000">blabla</font>
|
|
<li>
|
|
<b><tt><font color="#000099"><font size=+1>pair</font></font></tt></b></li>
|
|
|
|
<br><font color="#000000">This simple container allows you to hold two
|
|
data types together. It is very handy for temporary data handling. Assuming
|
|
p is a </font><tt><font color="#993300"><font size=+1>pair<AtomType1,
|
|
AtomType2></font></font></tt><font color="#000000">,</font>
|
|
<br><tt><font color="#993300"><font size=+1>p.first()</font></font></tt><font color="#000000">
|
|
and </font><tt><font color="#993300"><font size=+1>p.second()</font></font></tt><font color="#000000">
|
|
refer to the encapsulated data, of respective types </font><tt><font color="#993300"><font size=+1>AtomType1</font></font></tt><font color="#000000">and
|
|
</font><tt><font color="#993300"><font size=+1>AtomType2.</font></font></tt>
|
|
<li>
|
|
<b><tt><font color="#000099"><font size=+1>Blabla</font></font></tt></b></li>
|
|
</ul>
|
|
There are many other types of containers that are not used in EO and that
|
|
we will not present here.
|
|
<p><b><font color="#000099">STL Algorithms</font></b>
|
|
<br>Algorithms are functions acting on containers - the most widely used
|
|
example of a STL algorithm is the <b><font color="#FF6600">sort</font></b>
|
|
function.
|
|
<br>Blabla
|
|
<p><b><font color="#000099">Drawbacks</font></b>
|
|
<br>The main drawback I see in using STL is that it makes it almost
|
|
<b><font color="#FF6600">impossible
|
|
to use a debugger </font></b>normally: whereas access to data is made simple
|
|
to the programmer, data structures are actually so complex, and debuggers
|
|
so willing to display everything that you get lines of template instantiation
|
|
when asking your debugger what is inside some container! For instance I
|
|
could never visualize some
|
|
<tt><font color="#FF6600"><font size=+1>v[i]</font></font></tt>
|
|
with <tt><font color="#FF6600"><font size=+1>gbd</font></font></tt>, v
|
|
being an STL vector!
|
|
<br>But there nonetheless are so many advantages !!!
|
|
<p>
|
|
<hr WIDTH="100%">
|
|
<br><a NAME="random"></a><b><font color="#000099"><font size=+1>Random
|
|
numbers</font></font></b>
|
|
<br>Evolutionary Algorithms make intensive use of random numbers. Random
|
|
numbers are simulated in computers by using <font color="#FF6600">pseudo-random</font>
|
|
number generators (RNGs for short), i.e. functions that return series of
|
|
numbers who look random (w.r.t. some statistical criteria).
|
|
<p>To make sure the random number generator is as good as possible, and
|
|
to ensure reproducibility of the results across different platforms, EO
|
|
has its own RNG, the ``<font color="#FF6600">Mersenne Twister</font>''
|
|
random number generator MT19937 (thanks to <font color="#FF0000">Takuji
|
|
Nishimura</font>, see <font face="Arial,Helvetica"><font size=+1><a href="../../../../doc/html/class_eorng.html">eoRNG.h</a></font></font>
|
|
comments).
|
|
<p>Though you can define and use as many RNGs as you wish in EO, the library
|
|
also provides you with a global RNG termed rng: using only that single
|
|
RNG in all calls to random numbers allows one to be able to <b><font color="#FF6600">reproduce
|
|
a given run</font></b>:
|
|
<ul>
|
|
<li>
|
|
as strange it seems for a random algorithm, it is mandatory for debugging
|
|
purposes</li>
|
|
|
|
<li>
|
|
random numbers are computed starting from a seed - starting from the same
|
|
seed will lead to the same series of pseudo-random numbers, and hence to
|
|
the same results of the algorithms. All examples in this tutorial will
|
|
use the RNG seeding procedure, see e.g. in <a href="FirstBitGA.html#random">Lesson1</a>.</li>
|
|
|
|
<li>
|
|
to simulate "true" random runs, you can just seed the RNG with a machine-clock
|
|
related number, e.g. calling time(0), as done for instance in <a href="SecondBitEA.html#random">Lesson3</a>
|
|
(and after).</li>
|
|
</ul>
|
|
As RNGs only produce (by definition) numbers that are uniformly distributed
|
|
integers between 0 and some maximal number, EO provides you with random
|
|
numbers following <b><font color="#FF6600">different probability distribution</font></b>
|
|
(e.g. floating point following <font face="Arial,Helvetica"><font size=+1><a href="../../../../doc/html/class_eorng.html#a8">normal
|
|
distribution</a></font></font>).
|
|
<p>EO also provides <a href="../../../../doc/html/rnd_generators.h-source.html">random_generators</a>
|
|
that can be used in STL call to generate series of random numbers, as in
|
|
<a href="eoInit.html">eoPop
|
|
initializers</a>.
|
|
<p>
|
|
<hr WIDTH="100%">
|
|
<br><a NAME="notations"></a><b><font color="#000099"><font size=+1>EO conventions
|
|
and naming style</font></font></b>
|
|
<br>A few naming conventions should help you to navigate more easily through
|
|
EO:
|
|
<ul>
|
|
<li>
|
|
The name of local variables should start with a lower case letter</li>
|
|
|
|
<li>
|
|
The name of the parameters to a function should start with an underscore
|
|
(_)</li>
|
|
|
|
<br>The initialization parameters of constructors, for instance,
|
|
should be named from the names of the variables they are used to initialize.
|
|
<li>
|
|
The names of classes should start with eo + an Uppercase letter</li>
|
|
|
|
<li>
|
|
Blabla</li>
|
|
</ul>
|
|
|
|
<hr WIDTH="100%">
|
|
<br><a href="eoTutorial.html">Tutorial main page </a>- <a href="eoTopDown.html">Algorithm-Based
|
|
page</a> - <a href="eoBottomUp.html">Component-Based</a> - <a href="eoProgramming.html">Programming
|
|
hints</a> - <font face="Arial,Helvetica"><a href="../../doc/html/index.html">EO
|
|
documentation</a></font>
|
|
<br>
|
|
<hr>
|
|
<address>
|
|
<a href="mailto:Marc.Schoenauer@polytechnique.fr">Marc Schoenauer</a></address>
|
|
|
|
<br><!-- Created: Mon Oct 30 19:04:58 CET 2000 --><!-- hhmts start -->Last
|
|
modified: Mon Nov 6 07:01:57 CET 2000<!-- hhmts end -->
|
|
</body>
|
|
</html>
|