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    <title>User Guide - Overview</title>
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<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>Fitting a curve to a set of data points</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://commons.apache.org/mail-lists.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 sixteen subpackages, based on functionality provided.
    <ul>
      <li><a href="stat.html">org.apache.commons.math3.stat</a> - statistics, statistical tests</li>
      <li><a href="analysis.html">org.apache.commons.math3.analysis</a> - rootfinding, integration, interpolation, polynomials</li>
      <li><a href="random.html">org.apache.commons.math3.random</a> - random numbers, strings and data generation</li>
      <li><a href="special.html">org.apache.commons.math3.special</a> - special functions (Gamma, Beta) </li>
      <li><a href="linear.html">org.apache.commons.math3.linear</a> - matrices, solving linear systems </li>
      <li><a href="utilities.html">org.apache.commons.math3.util</a> - common math/stat functions extending java.lang.Math </li>
      <li><a href="complex.html">org.apache.commons.math3.complex</a> - complex numbers</li>
      <li><a href="distribution.html">org.apache.commons.math3.distribution</a> - probability distributions</li>
      <li><a href="fraction.html">org.apache.commons.math3.fraction</a> - rational numbers</li>
      <li><a href="transform.html">org.apache.commons.math3.transform</a> - transform methods (Fast Fourier)</li>
      <li><a href="geometry.html">org.apache.commons.math3.geometry</a> - geometry (Euclidean spaces and Binary Space Partitioning)</li>
      <li><a href="optimization.html">org.apache.commons.math3.optim</a> - function maximization or minimization</li>
      <li><a href="ode.html">org.apache.commons.math3.ode</a> - Ordinary Differential Equations integration</li>
      <li><a href="genetics.html">org.apache.commons.math3.genetics</a> - Genetic Algorithms</li>
      <li><a href="fitting.html">org.apache.commons.math3.fitting</a> - Curve Fitting</li>
      <li><a href="ml.html">org.apache.commons.math3.ml</a> - Machine Learning</li>
    </ul>
    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, a
    <a href="../apidocs/org/apache/commons/math3/exception/MathIllegalArgumentException.html">
      MathIllegalArgumentException</a> or
    <a href="../apidocs/org/apache/commons/math3/exception/MathIllegalStateException.html">
    MathIllegalStateException</a> 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 <code>Double.NaN</code> values. Conditions under which <code>Double.NaN</code>
    or other special values are returned are fully specified in the javadoc method comments.
  </p>
  <p>
    As of version 2.2, the policy for dealing with null references is as
    follows: When an argument is unexpectedly null, a
    <a href="../apidocs/org/apache/commons/math3/exception/NullArgumentException.html">
    NullArgumentException</a> is raised to signal the illegal argument. Note that this
    class does not inherit from the standard <code>NullPointerException</code> but is a subclass
    of <code>MathIllegalArgumentException</code>.
  </p>
</subsection>

<subsection name="0.5 Dependencies" href="dependencies">
    <p>
    Commons Math requires JDK 1.5+ and has no runtime dependencies.
    </p>
</subsection>

<subsection name="0.6 License" href="license">
    <p>
    Commons Math is distributed under the terms of the Apache License, Version 2.0:
    <a href="http://www.apache.org/licenses/LICENSE-2.0"/>.
    </p>

    <p>
    This product includes software developed by other third parties and
    distributed under licenses terms compatible with Apache License, Version 2.0.
    All the licenses of such third parties products are available in the distribution
    in the LICENSE.txt file. Some products require additional attribution, these
    attributions can be found in the NOTICE.txt file. These files are available
    both in the source packages and in the binaries distribution jar files.
    </p>

</subsection>

</section>

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