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cycle_floyd.html
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<html>
<head>
<title>
CYCLE_FLOYD - Cycle Detection by Floyd's Method
</title>
</head>
<body bgcolor="#EEEEEE" link="#CC0000" alink="#FF3300" vlink="#000055">
<h1 align = "center">
CYCLE_FLOYD <br> Cycle Detection by Floyd's Method
</h1>
<hr>
<p>
<b>CYCLE_FLOYD</b>
is a FORTRAN90 library which
analyzes a cycle in an iterated function sequence using Floyd's method.
</p>
<p>
Suppose we a repeatedly apply a function f(), starting with the argument
x0, then f(x0), f(f(x0)) and so on. Suppose that the range of f is finite.
Then eventually the iteration must reach a cycle. Once the cycle is reached,
succeeding values stay within that cycle.
</p>
<p>
Starting at x0, there is a "nearest element" of the cycle, which is
reached after MU applications of f.
</p>
<p>
Once the cycle is entered, the cycle has a length LAM, which is the number
of steps required to first return to a given value.
</p>
<p>
This function uses Floyd's method to determine the values of MU and LAM,
given F and X0.
</p>
<h3 align = "center">
Licensing:
</h3>
<p>
The computer code and data files described and made available on this
web page are distributed under
<a href = "../../txt/gnu_lgpl.txt">the GNU LGPL license.</a>
</p>
<h3 align = "center">
Languages:
</h3>
<p>
<b>CYCLE_FLOYD</b> is available in
<a href = "../../c_src/cycle_floyd/cycle_floyd.html">a C version</a> and
<a href = "../../cpp_src/cycle_floyd/cycle_floyd.html">a C++ version</a> and
<a href = "../../f77_src/cycle_floyd/cycle_floyd.html">a FORTRAN77 version</a> and
<a href = "../../f_src/cycle_floyd/cycle_floyd.html">a FORTRAN90 version</a> and
<a href = "../../m_src/cycle_floyd/cycle_floyd.html">a MATLAB version</a>.
</p>
<h3 align = "center">
Related Data and Programs:
</h3>
<p>
<a href = "../../f_src/cycle_brent/cycle_brent.html">
CYCLE_BRENT</a>,
a FORTRAN90 library which
carries out an iterated function evaluation, and seeks to determine the
nearest element of a cycle, and the cycle's length, using Brent's method.
</p>
<h3 align = "center">
Reference:
</h3>
<p>
<ol>
<li>
Donald Knuth,<br>
The Art of Computer Programming,<br>
Volume 2, Seminumerical Algorithms,<br>
Third Edition,<br>
Addison Wesley, 1997,<br>
ISBN: 0201896842,<br>
LC: QA76.6.K64.
</li>
</ol>
</p>
<h3 align = "center">
Source Code:
</h3>
<p>
<ul>
<li>
<a href = "cycle_floyd.f90">cycle_floyd.f90</a>, the source code.
</li>
<li>
<a href = "cycle_floyd.sh">cycle_floyd.sh</a>,
BASH commands to compile the source code.
</li>
</ul>
</p>
<h3 align = "center">
Examples and Tests:
</h3>
<p>
<ul>
<li>
<a href = "cycle_floyd_prb.f90">cycle_floyd_prb.f90</a>,
a sample calling program.
</li>
<li>
<a href = "cycle_floyd_prb.sh">cycle_floyd_prb.sh</a>,
BASH commands to compile and run the sample program.
</li>
<li>
<a href = "cycle_floyd_prb_output.txt">cycle_floyd_prb_output.txt</a>,
the output file.
</li>
</ul>
</p>
<h3 align = "center">
List of Routines:
</h3>
<p>
<ul>
<li>
<b>CYCLE_FLOYD</b> finds a cycle in an iterated mapping using Floyd's method.
</li>
<li>
<b>TIMESTAMP</b> prints the current YMDHMS date as a time stamp.
</li>
</ul>
</p>
<p>
You can go up one level to <a href = "../f_src.html">
the FORTRAN90 source codes</a>.
</p>
<hr>
<i>
Last revised on 14 June 2012.
</i>
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</body>
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</html>