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<h2>
<span class="refentrytitle">randi</span>
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<p>rand —
Generates a controlled random number series with interpolation between each new number.
</p>
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<div class="refsect1" title="Description">
<a id="id3150954"></a>
<h2>Description</h2>
<p>
Generates a controlled random number series with interpolation between each new number.
</p>
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<div class="refsect1" title="Syntax">
<a id="id3150967"></a>
<h2>Syntax</h2>
<pre class="synopsis">ares <span class="command"><strong>randi</strong></span> xamp, xcps [, iseed] [, isize] [, ioffset]</pre>
<pre class="synopsis">kres <span class="command"><strong>randi</strong></span> kamp, kcps [, iseed] [, isize] [, ioffset]</pre>
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<div class="refsect1" title="Initialization">
<a id="id3151196"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>iseed</em></span> (optional, default=0.5) -- seed value for the recursive pseudo-random formula. A value between 0 and +1 will produce an initial output of <span class="emphasis"><em>kamp * iseed.</em></span> A negative value will cause seed re-initialization to be skipped. A value greater than 1 will seed from system time, this is the best option to generate a different random sequence for each run.
</p>
<p>
<span class="emphasis"><em>isize</em></span> (optional, default=0) -- if zero, a 16 bit number is generated. If non-zero, a 31-bit random number is generated. Default is 0.
</p>
<p>
<span class="emphasis"><em>ioffset</em></span> (optional, default=0) -- a base value added to the random result. New in Csound version 4.03.
</p>
</div>
<div class="refsect1" title="Performance">
<a id="id3151832"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>kamp, xamp</em></span> -- range over which random numbers are distributed.
</p>
<p>
<span class="emphasis"><em>kcps, xcps</em></span> -- the frequency which new random numbers are generated.
</p>
<p>
The internal pseudo-random formula produces values which are uniformly distributed over the range <span class="emphasis"><em>kamp</em></span> to <span class="emphasis"><em>-kamp</em></span>. <span class="emphasis"><em>rand</em></span> will thus generate uniform white noise with an R.M.S value of <span class="emphasis"><em>kamp / root 2</em></span>.
</p>
<p>
The remaining units produce band-limited noise: the <span class="emphasis"><em>kcps</em></span> and <span class="emphasis"><em>xcps</em></span> parameters permit the user to specify that new random numbers are to be generated at a rate less than the sampling or control frequencies. <span class="emphasis"><em>randi</em></span> will produce straight-line interpolation between each new number and the next.
</p>
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<div class="refsect1" title="Examples">
<a id="id3151898"></a>
<h2>Examples</h2>
<p>
Here is an example of the randi opcode. It uses the file <a class="ulink" href="examples/randi.csd" target="_top"><em class="citetitle">randi.csd</em></a>.
</p>
<div class="example">
<a id="id3151915"></a>
<p class="title">
<b>Example 513. Example of the randi opcode.</b>
</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>
<pre class="programlisting">
<span class="csdtag"><CsoundSynthesizer></span>
<span class="csdtag"><CsOptions></span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out Audio in</span>
-odac -iadc <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o randi.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="comment">; Initialize the global variables.</span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 4410
<span class="ohdr">ksmps</span> <span class="op">=</span> 10
<span class="ohdr">nchnls</span> <span class="op">=</span> 1
<span class="comment">; Instrument #1.</span>
<span class="oblock">instr</span> 1
<span class="comment">; Choose a random frequency between 4,100 and 44,100.</span>
<span class="comment">; Generate new random numbers at 10 Hz.</span>
<span class="comment">; kamp = 40000</span>
<span class="comment">; kcps = 10</span>
<span class="comment">; iseed = 0.5</span>
<span class="comment">; isize = 0</span>
<span class="comment">; ioffset = 4100</span>
kcps <span class="opc">randi</span> 40000, 10, 0.5, 0, 4100
a1 <span class="opc">oscil</span> 30000, kcps, 1
<span class="opc">out</span> a1
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="comment">; Table #1, a sine wave.</span>
<span class="stamnt">f</span> 1 0 16384 10 1
<span class="comment">; Play Instrument #1 for one second.</span>
<span class="stamnt">i</span> 1 0 1
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
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<p><br class="example-break" />
</p>
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<div class="refsect1" title="See Also">
<a id="id3151953"></a>
<h2>See Also</h2>
<p>
<a class="link" href="rand.html" title="rand"><em class="citetitle">rand</em></a>,
<a class="link" href="randh.html" title="randh"><em class="citetitle">randh</em></a>
</p>
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<div class="refsect1" title="Credits">
<a id="id3151979"></a>
<h2>Credits</h2>
<p>Example written by Kevin Conder.</p>
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