71 lines
1.1 KiB
Text
71 lines
1.1 KiB
Text
|
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;
|
||
|
|
)
|
||
|
|
::
|