87 lines
1.3 KiB
Text
87 lines
1.3 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{Pgbrown}
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geometric brownian motion pattern@section{related}
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Classes/BrownNoise, Classes/Pbrown
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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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Returns a stream that behaves like a geometric brownian motion.
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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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lo
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lower boundary of values.
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@section{argument}
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hi
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upper boundary of values.
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@section{argument}
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step
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maximum multiplication factor per step (omega) - the distribution is xrand2.
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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, b;
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a = Pgbrown(0.0, 1.0, 0.2, inf);
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b = a.asStream;
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7.do({ b.next.postln; });
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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 = Pgbrown(1.0, 2.0, 0.1, inf).asStream;
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Routine({
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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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}).play;
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)
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// compare with normal brownian motion:
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(
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var a;
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a = Pbrown(1.0, 2.0, 0.1, inf).asStream;
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Routine({
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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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}).play;
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)
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::
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]
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