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class:: Pgbrown
summary:: geometric brownian motion pattern
related:: Classes/BrownNoise, Classes/Pbrown
categories:: Streams-Patterns-Events>Patterns>Random
description::
Returns a stream that behaves like a geometric brownian motion.
ClassMethods::
method::new
argument::lo
lower boundary of values.
argument::hi
upper boundary of values.
argument::step
maximum multiplication factor per step (omega) - the distribution is xrand2.
argument::length
number of values produced.
Examples::
code::
(
var a, b;
a = Pgbrown(0.0, 1.0, 0.2, inf);
b = a.asStream;
7.do({ b.next.postln; });
)
// sound example
(
SynthDef(\help_sinegrain,
{ arg out=0, freq=440, sustain=0.05;
var env;
env = EnvGen.kr(Env.perc(0.01, sustain, 0.2), doneAction: Done.freeSelf);
Out.ar(out, SinOsc.ar(freq, 0, env))
}).add;
)
(
var a;
a = Pgbrown(1.0, 2.0, 0.1, inf).asStream;
Routine({
loop({
Synth(\help_sinegrain, [\freq, a.next * 600 + 300]);
0.02.wait;
})
}).play;
)
// compare with normal brownian motion:
(
var a;
a = Pbrown(1.0, 2.0, 0.1, inf).asStream;
Routine({
loop({
Synth(\help_sinegrain, [\freq, a.next * 600 + 300]);
0.02.wait;
})
}).play;
)
::
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