commons-math/xdocs/userguide/overview.xml

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<?xml version="1.0"?>
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<document>
<properties>
<title>User Guide - Overview</title>
</properties>
<body>
<section name="Overview">
<subsection name="0.1 About The User Guide" href="about">
<p>
This guide is intended to help programmers quickly find what they need to develop
solutions using Commons Math. It also provides a supplement to the javadoc API documentation,
providing a little more explanation of the mathematical objects and functions included
in the package.
</p>
</subsection>
<subsection name="0.2 What's in commons-math" href="summary">
<p>
Commons Math is made up of a small set of math/stat utilities addressing
programming problems like the ones in the list below. This list is not exhaustive,
it's just meant to give a feel for the kinds of things that Commons Math provides.
<ul>
<li>Computing means, variances and other summary statistics for a list of numbers</li>
<li>Fitting a line to a set of data points using linear regression</li>
<li>Finding a smooth curve that passes through a collection of points (interpolation)</li>
<li>Fitting a parametric model to a set of measurements using least-squares methods</li>
<li>Solving equations involving real-valued functions (i.e. root-finding)</li>
<li>Solving systems of linear equations</li>
<li>Solving Ordinary Differential Equations</li>
<li>Minimizing multi-dimensional functions</li>
<li>Generating random numbers with more restrictions (e.g distribution, range) than what
is possible using the JDK</li>
<li>Generating random samples and/or datasets that are "like" the data in an input file</li>
<li>Performing statistical significance tests</li>
<li>Miscellaneous mathematical functions such as factorials, binomial
coefficients and "special functions" (e.g. gamma, beta functions)</li>
</ul></p>
<p>
We are actively seeking ideas for additional components that fit into the
<a href="../index.html#summary">Commons Math vision</a> of a set of lightweight,
self-contained math/stat components useful for solving common programming problems.
Suggestions for new components or enhancements to existing functionality are always welcome!
All feedback/suggestions for improvement should be sent to the
<a href="http://jakarta.apache.org/site/mail.html">commons-dev mailing list</a> with
[math] at the beginning of the subject line.
</p>
</subsection>
<subsection name="0.3 How commons-math is organized" href="organization">
<p>
Commons Math is divided into fourteen subpackages, based on functionality provided.
<ol>
<li><a href="stat.html">org.apache.commons.math.stat</a> - statistics, statistical tests</li>
<li><a href="analysis.html">org.apache.commons.math.analysis</a> - rootfinding and interpolation</li>
<li><a href="random.html">org.apache.commons.math.random</a> - random numbers, strings and data generation</li>
<li><a href="special.html">org.apache.commons.math.special</a> - special functions (Gamma, Beta) </li>
<li><a href="linear.html">org.apache.commons.math.linear</a> - matrices, solving linear systems </li>
<li><a href="utilities.html">org.apache.commons.math.util</a> - common math/stat functions extending java.lang.Math </li>
<li><a href="complex.html">org.apache.commons.math.complex</a> - complex numbers</li>
<li><a href="distribution.html">org.apache.commons.math.distribution</a> - probability distributions</li>
<li><a href="fraction.html">org.apache.commons.math.fraction</a> - rational numbers</li>
<li><a href="transform.html">org.apache.commons.math.transform</a> - transform methods (Fast Fourier)</li>
<li><a href="geometry.html">org.apache.commons.math.geometry</a> - 3D geometry (vectors and rotations)</li>
<li><a href="estimation.html">org.apache.commons.math.estimation</a> - parametric estimation problems</li>
<li><a href="optimization.html">org.apache.commons.math.optimization</a> - multi-dimensional functions minimization</li>
<li><a href="ode.html">org.apache.commons.math.ode</a> - Ordinary Differential Equations integration</li>
</ol>
Package javadocs are <a href="../apidocs/index.html">here</a>
</p>
</subsection>
<subsection name="0.4 How interface contracts are specified in commons-math javadoc" href="contracts">
<p>
You should always read the javadoc class and method comments carefully when using
Commons Math components in your programs. The javadoc provides references to the algorithms
that are used, usage notes about limitations, performance, etc. as well as interface contracts.
Interface contracts are specified in terms of preconditions (what has to be true in order
for the method to return valid results), special values returned (e.g. Double.NaN)
or exceptions that may be thrown if the preconditions are not met, and definitions for returned
values/objects or state changes.</p>
<p>
When the actual parameters provided to a method or the internal state of an object
make a computation meaningless, an IllegalArgumentException or IllegalStateException may
be thrown. Exact conditions under which runtime exceptions (and any other exceptions) are
thrown are specified in the javadoc method comments. In some cases, to be consistent with
the <a href="http://grouper.ieee.org/groups/754/">IEEE 754 standard</a> for floating point
arithmetic and with java.lang.Math, Commons Math methods return Double.NaN values.
Conditions under which Double.NaN or other special values are returned are fully specified
in the javadoc method comments.
</p>
</subsection>
<subsection name="0.5 Dependencies" href="dependencies">
<p>
Commons Math requires JDK 1.3+ and has no runtime dependencies. Commons
Discovery is used to enable pluggable implementations in the
<code>distributions, analysis</code> and <code>stat</code> packages; but
default implementations are used if the commons-discovery and
commons-logging (a dependency of commons-discovery) jars are not present in
the classpath. To compile the sources, the following versions of these
components are required:
<ul>
<li>commons-discovery 0.2 </li>
<li>commons-logging 1.0.3 </li>
</ul>
</p>
</subsection>
</section>
</body>
</document>