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<h2>
<span class="refentrytitle">GEN04</span>
</h2>
<p>GEN04 —
Generates a normalizing function.
</p>
</div>
<div class="refsect1" title="Description">
<a id="idp77170840"></a>
<h2>Description</h2>
<p>
This subroutine generates a normalizing function by examining the contents of an existing table.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="idp77171552"></a>
<h2>Syntax</h2>
<pre class="synopsis"><span class="command"><strong>f</strong></span> # time size 4 source# sourcemode</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="idp77229880"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>size</em></span> -- number of points in the table. Should be power-of-2 plus 1. Must not exceed (except by 1) the size of the source table being examined; limited to just half that size if the sourcemode is of type offset (see below).
</p>
<p>
<span class="emphasis"><em>source #</em></span> -- table number of stored function to be examined.
</p>
<p>
<span class="emphasis"><em>sourcemode</em></span> -- a coded value, specifying how the source table is to be scanned to obtain the normalizing function. Zero indicates that the source is to be scanned from left to right. Non-zero indicates that the source has a bipolar structure; scanning will begin at the mid-point and progress outwards, looking at pairs of points equidistant from the center.
</p>
<div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;">
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<th align="left">Note</th>
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<p>
</p>
<div class="itemizedlist">
<ul class="itemizedlist" type="disc">
<li class="listitem">
<p>
The normalizing function derives from the progressive absolute maxima of the source table being scanned. The new table is created left-to-right, with stored values equal to 1/(absolute maximum so far scanned). Stored values will thus begin with 1/(first value scanned), then get progressively smaller as new maxima are encountered. For a source table which is normalized (values <= 1), the derived values will range from 1/(first value scanned) down to 1. If the first value scanned is zero, that inverse will be set to 1.
</p>
</li>
<li class="listitem">
<p>
The normalizing function from <span class="emphasis"><em>GEN04</em></span> is not itself normalized.
</p>
</li>
<li class="listitem">
<p>
<span class="emphasis"><em>GEN04</em></span> is useful for scaling a table-derived signal so that it has a consistent peak amplitude. A particular application occurs in waveshaping when the carrier (or indexing) signal is less than full amplitude.
</p>
</li>
</ul>
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<p>
</p>
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</div>
<div class="refsect1" title="Examples">
<a id="idp77235624"></a>
<h2>Examples</h2>
<p>
Here is a simple example of the GEN04 routine. It uses the files <a class="ulink" href="examples/gen04.csd" target="_top"><em class="citetitle">gen04.csd</em></a>.
</p>
<div class="example">
<a id="idp77236600"></a>
<p class="title">
<strong>Example 1040. An example of the GEN04 routine.</strong>
</p>
<div class="example-contents">
<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>
-odac <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o gen04.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 2
<span class="ohdr">0dbfs</span> <span class="op">=</span> 1
gisine <span class="ohdr">ftgen</span> 0, 0, 16384, 10, 1 <span class="comment">;sine wave</span>
<span class="oblock">instr</span> 1
ihertz <span class="op">=</span> <span class="opc">cpspch</span>(p4)
ipkamp <span class="op">=</span> p5
iwsfn <span class="op">=</span> p6 <span class="comment">;waveshaping function </span>
inmfn <span class="op">=</span> p7 <span class="comment">;normalization function </span>
agate <span class="opc">linen</span> 1, .01, p3, .1 <span class="comment">;overall amp envelope</span>
kctrl <span class="opc">linen</span> .9, 2, p3, 2 <span class="comment">;waveshaping index control</span>
aindex <span class="opc">poscil</span> kctrl<span class="op">/</span>2, ihertz, gisine <span class="comment">;sine wave to be distorted</span>
asignal <span class="opc">tablei</span> .5<span class="op">+</span>aindex, iwsfn, 1 <span class="comment">;waveshaping</span>
knormal <span class="opc">tablei</span> 1<span class="op">/</span>kctrl, inmfn , 1 <span class="comment">;amplitude normalization</span>
<span class="opc">outs</span> asignal<span class="op">*</span>knormal<span class="op">*</span>ipkamp<span class="op">*</span>agate, asignal<span class="op">*</span>knormal<span class="op">*</span>ipkamp<span class="op">*</span>agate
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="stamnt">f</span>1 0 64 21 6 <span class="comment">;Gaussian (random) distribution</span>
<span class="stamnt">f</span>2 0 33 4 1 1 <span class="comment">;normalizing function with midpoint bipolar offset</span>
<span class="stamnt">s</span>
<span class="comment">; st dur pch amp wsfn inmfn</span>
<span class="stamnt">i</span>1 0 4 6.00 .7 1 2
<span class="stamnt">i</span>1 4 . 7.00 .
<span class="stamnt">i</span>1 8 . 8.00 .
<span class="comment">;-------------------------------------------------------------------------------------</span>
<span class="stamnt">f</span>3 0 1025 13 1 1 0 5 0 5 0 10 <span class="comment">;Chebyshev algorithm</span>
<span class="stamnt">f</span>4 0 513 4 3 1 <span class="comment">;normalizing function with midpoint bipolar offset</span>
<span class="stamnt">s</span>
<span class="comment">; st dur pch amp wsfn inmfn</span>
<span class="stamnt">i</span>1 0 4 6.00 .9 3 4
<span class="stamnt">i</span>1 4 . 7.00 .
<span class="stamnt">i</span>1 8 . 8.00 .
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
</div>
<p><br class="example-break" />
<span>These are the diagrams of the waveforms of the GEN04 routines, as used in the example:</span>
</p>
<div class="mediaobject">
<img src="images/gen04_1.png" alt="f1 0 64 21 6 - Gaussian (random) distribution" />
<div class="caption">
<p>f1 0 64 21 6 - Gaussian (random) distribution</p>
</div>
</div>
<p>
</p>
<div class="mediaobject">
<img src="images/gen04_2.png" alt="f2 0 33 4 1 1 - AND its normalizing function with midpoint bipolar offset" />
<div class="caption">
<p>f2 0 33 4 1 1 - AND its normalizing function with midpoint bipolar offset</p>
</div>
</div>
<p>
</p>
<div class="mediaobject">
<img src="images/gen04_3.png" alt="f3 0 1025 13 1 1 0 5 0 5 0 10 - Chebyshev algorithm" />
<div class="caption">
<p>f3 0 1025 13 1 1 0 5 0 5 0 10 - Chebyshev algorithm</p>
</div>
</div>
<p>
</p>
<div class="mediaobject">
<img src="images/gen04_4.png" alt="f4 0 513 4 3 1 - AND its normalizing function with midpoint bipolar offset" />
<div class="caption">
<p>f4 0 513 4 3 1 - AND its normalizing function with midpoint bipolar offset</p>
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