87 lines
1.6 KiB
Text
87 lines
1.6 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{Pgauss}
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random values that follow a Gaussian Distribution@section{related}
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Classes/Ppoisson
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@section{categories}
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Streams-Patterns-Events>Patterns>Random
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@section{description}
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This pattern uses the Box-Muller transform to generate a gaussian distribution from uniformly distributed values:
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@racketblock[sqrt(-2 * log(1.0.rand)) * sin(2pi.rand)::
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]
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@section{ClassMethods}
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@section{method}
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new
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@section{argument}
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mean
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The mean of the distribution.
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@section{argument}
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dev
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The spread of values around the mean (standard deviation).
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@section{argument}
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length
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Number of values produced.
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@section{Examples}
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@racketblock[
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(
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var a;
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a = Pgauss(0.0, 100, inf);
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c = a.asStream.nextN(500);
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w = Window.new("Pgauss", Rect(10, 10, 540, 800));
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// plot the values
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c.plot(bounds: Rect(10, 10, 520, 380), discrete: true, parent: w);
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// a histogram of the values
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c.histo(500).plot(bounds: Rect(10, 410, 520, 380), parent: w);
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)
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(
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var a, c, w;
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a = Pgauss(0.0, 10.0, inf);
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c = a.asStream.nextN(500);
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w = Window.new("Pgauss", Rect(10, 10, 540, 800));
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// plot the values
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c.plot(bounds: Rect(10, 10, 520, 380), discrete: true, parent: w);
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// a histogram of the values
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c.histo(500).plot(bounds: Rect(10, 410, 520, 380), parent: w);
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)
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// sound example
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(
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SynthDef(\help_sinegrain,
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{ arg out=0, freq=440, sustain=0.05;
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var env;
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env = EnvGen.kr(Env.perc(0.01, sustain, 0.2), doneAction: Done.freeSelf);
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Out.ar(out, SinOsc.ar(freq, 0, env))
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}).add;
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)
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(
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var a;
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a = Pgauss(0.0, 1.0,inf).asStream;
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{
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loop {
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Synth(\help_sinegrain, [\freq, a.next * 600 + 300]);
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0.02.wait;
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}
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}.fork;
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)
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::
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]
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