<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>gauss</title> <link rel="stylesheet" type="text/css" href="csound.css" /> <link rel="stylesheet" type="text/css" href="syntax-highlighting.css" /> <meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /> <link rel="home" href="index.html" title="The Canonical Csound Reference Manual" /> <link rel="up" href="OpcodesTop.html" title="Orchestra Opcodes and Operators" /> <link rel="prev" href="gainslider.html" title="gainslider" /> <link rel="next" href="gaussi.html" title="gaussi" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">gauss</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="gainslider.html">Prev</a> </td> <th width="60%" align="center">Orchestra Opcodes and Operators</th> <td width="20%" align="right"> <a accesskey="n" href="gaussi.html">Next</a></td> </tr> </table> <hr /> </div> <div class="refentry"> <a id="gauss"></a> <div class="titlepage"></div> <a id="IndexGaussXClass" class="indexterm"></a> <a id="IndexGauss" class="indexterm"></a> <div class="refnamediv"> <h2> <span class="refentrytitle">gauss</span> </h2> <p>gauss — Gaussian distribution random number generator. </p> </div> <div class="refsect1"> <a id="idm281472927869096"></a> <h2>Description</h2> <p> Gaussian distribution random number generator. This is an x-class noise generator. </p> </div> <div class="refsect1"> <a id="idm281472927796616"></a> <h2>Syntax</h2> <pre class="synopsis">ares <span class="command"><strong>gauss</strong></span> krange</pre> <pre class="synopsis">ires <span class="command"><strong>gauss</strong></span> krange</pre> <pre class="synopsis">kres <span class="command"><strong>gauss</strong></span> krange</pre> </div> <div class="refsect1"> <a id="idm281472927791656"></a> <h2>Performance</h2> <p> <span class="emphasis"><em>krange</em></span> -- the range of the random numbers (-<span class="emphasis"><em>krange</em></span> to +<span class="emphasis"><em>krange</em></span>). Outputs both positive and negative numbers. </p> <p> <span class="emphasis"><em>gauss</em></span> returns random numbers following a normal distribution centered around 0.0 (mu = 0.0) with a variance (sigma) of <span class="emphasis"><em>krange</em></span> / 3.83. Thus more than 99.99% of the random values generated are in the range -<span class="emphasis"><em>krange</em></span> to +<span class="emphasis"><em>krange</em></span>. If a mean value different of 0.0 is desired, this mean value has to be added to the generated numbers (see example below). </p> <p> For more detailed explanation of these distributions, see: </p> <div class="orderedlist"> <ol class="orderedlist" type="1"> <li class="listitem"> <p>C. Dodge - T.A. Jerse 1985. Computer music. Schirmer books. pp.265 - 286</p> </li> <li class="listitem"> <p>D. Lorrain. A panoply of stochastic cannons. In C. Roads, ed. 1989. Music machine . Cambridge, Massachusetts: MIT press, pp. 351 - 379.</p> </li> </ol> </div> <p> </p> </div> <div class="refsect1"> <a id="idm281472927783544"></a> <h2>Examples</h2> <p> Here is an example of the gauss opcode. It uses the file <a class="ulink" href="examples/gauss.csd" target="_top"><em class="citetitle">gauss.csd</em></a>. </p> <div class="example"> <a id="idm281472927781688"></a> <p class="title"> <strong>Example 371. Example of the gauss opcode.</strong> </p> <div class="example-contents"> <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p> <div class="refsect1"> <a id="idm281472757923848"></a> <pre class="programlisting"> <span class="nt"><CsoundSynthesizer></span> <span class="nt"><CsOptions></span> -d -o dac <span class="nt"></CsOptions></span> <span class="nt"><CsInstruments></span> <span class="kd">instr</span> <span class="nf">1</span> i<span class="n">range</span> <span class="o">=</span> <span class="nb">p4</span> i<span class="n">mu</span> <span class="o">=</span> <span class="nb">p5</span> i<span class="n">samples</span> <span class="o">=</span> <span class="nb">p6</span> i<span class="n">ndx</span> <span class="o">=</span> <span class="mi">0</span> i<span class="n">count</span> <span class="o">=</span> <span class="mi">1</span> i<span class="n">x</span> <span class="o">=</span> <span class="mf">0.0</span> i<span class="n">x2</span> <span class="o">=</span> <span class="mf">0.0</span> <span class="nl">loop</span><span class="p">:</span> i<span class="n">1</span> <span class="nb">gauss</span> i<span class="n">range</span> i<span class="n">1</span> <span class="o">=</span> i<span class="n">1</span> <span class="o">+</span> i<span class="n">mu</span> i<span class="n">x</span> <span class="o">=</span> i<span class="n">x</span> <span class="o">+</span> i<span class="n">1</span> i<span class="n">x2</span> <span class="o">=</span> i<span class="n">x2</span> <span class="o">+</span> i<span class="n">1</span><span class="o">*</span>i<span class="n">1</span> <span class="k">if</span> i<span class="n">1</span> <span class="o">>=</span> <span class="o">-</span><span class="p">(</span>i<span class="n">range</span><span class="o">+</span>i<span class="n">mu</span><span class="p">)</span> <span class="o">&&</span> i<span class="n">1</span> <span class="o"><=</span> <span class="p">(</span>i<span class="n">range</span><span class="o">+</span>i<span class="n">mu</span><span class="p">)</span> <span class="k">then</span> i<span class="n">count</span> <span class="o">=</span> i<span class="n">count</span><span class="o">+</span><span class="mi">1</span> <span class="k">endif</span> <span class="k">loop_lt</span> i<span class="n">ndx</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> i<span class="n">samples</span><span class="p">,</span> <span class="nl">loop</span> i<span class="n">mean</span> <span class="o">=</span> i<span class="n">x</span> <span class="o">/</span> i<span class="n">samples</span> <span class="c1">;mean value</span> i<span class="n">std</span> <span class="o">=</span> <span class="nb">sqrt</span><span class="p">(</span>i<span class="n">x2</span><span class="o">/</span>i<span class="n">samples</span> <span class="o">-</span> i<span class="n">mean</span><span class="o">*</span>i<span class="n">mean</span><span class="p">)</span> <span class="c1">;standard deviation</span> <span class="nb">prints</span> <span class="s">"mean = %3.3f, std = %3.3f, "</span><span class="p">,</span> i<span class="n">mean</span><span class="p">,</span> i<span class="n">std</span> <span class="nb">prints</span> <span class="s">"samples inside the given range: %3.3f\%</span><span class="se">\n</span><span class="s">"</span><span class="p">,</span> i<span class="n">count</span><span class="o">*</span><span class="mf">100.0</span><span class="o">/</span>i<span class="n">samples</span> <span class="kd">endin</span> <span class="nt"></CsInstruments></span> <span class="nt"><CsScore></span> <span class="nb">i</span> <span class="mi">1</span> <span class="mi">0</span> <span class="mf">0.1</span> <span class="mf">1.0</span> <span class="mi">0</span> <span class="mi">100000</span> <span class="c1">; range = 1, mu = 0.0, sigma = 1/3.83 = 0.261</span> <span class="nb">i</span> <span class="mi">1</span> <span class="mf">0.1</span> <span class="mf">0.1</span> <span class="mf">3.83</span> <span class="mi">0</span> <span class="mi">100000</span> <span class="c1">; range = 3.83, mu = 0.0, sigma = 1</span> <span class="nb">i</span> <span class="mi">1</span> <span class="mf">0.2</span> <span class="mf">0.1</span> <span class="mf">5.745</span> <span class="mf">2.7</span> <span class="mi">100000</span> <span class="c1">; range = 5.745, mu = 2.7, sigma = 5.745/3.83 = 1.5</span> <span class="nt"></CsScore></span> <span class="nt"></CsoundSynthesizer></span> </pre> </div> </div> </div> <p><br class="example-break" /> Its output should include lines like this: </p> <pre class="screen"> mean = 0.000, std = 0.260, samples inside the given range: 99.993% mean = 0.005, std = 0.999, samples inside the given range: 99.998% mean = 2.700, std = 1.497, samples inside the given range: 100.000%</pre> <p> </p> </div> <div class="refsect1"> <a id="idm281472927776472"></a> <h2>See Also</h2> <p> <a class="link" href="seed.html" title="seed"><em class="citetitle">seed</em></a>, <a class="link" href="betarand.html" title="betarand"><em class="citetitle">betarand</em></a>, <a class="link" href="bexprnd.html" title="bexprnd"><em class="citetitle">bexprnd</em></a>, <a class="link" href="cauchy.html" title="cauchy"><em class="citetitle">cauchy</em></a>, <a class="link" href="exprand.html" title="exprand"><em class="citetitle">exprand</em></a>, <a class="link" href="linrand.html" title="linrand"><em class="citetitle">linrand</em></a>, <a class="link" href="pcauchy.html" title="pcauchy"><em class="citetitle">pcauchy</em></a>, <a class="link" href="poisson.html" title="poisson"><em class="citetitle">poisson</em></a>, <a class="link" href="trirand.html" title="trirand"><em class="citetitle">trirand</em></a>, <a class="link" href="unirand.html" title="unirand"><em class="citetitle">unirand</em></a>, <a class="link" href="weibull.html" title="weibull"><em class="citetitle">weibull</em></a> </p> </div> <div class="refsect1"> <a id="idm281472927764792"></a> <h2>Credits</h2> <p> </p> <table border="0" summary="Simple list" class="simplelist"> <tr> <td>Author: Paris Smaragdis</td> </tr> <tr> <td>MIT, Cambridge</td> </tr> <tr> <td>1995</td> </tr> </table> <p> </p> <p>Precisions about mu and sigma added by François Pinot after a discussion with Joachim Heintz on the Csound List, December 2010.</p> <p>Example written by François Pinot, adapted from a csd file by Joachim Heintz, December 2010.</p> <p>Existed in 3.30</p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="gainslider.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="OpcodesTop.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="gaussi.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">gainslider </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> gaussi</td> </tr> </table> </div> </body> </html>