43 lines
948 B
Text
43 lines
948 B
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{(standard-l rate freq k xi yi)}
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(standard-n rate freq k xi yi)
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Standard map chaotic generator.
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freq - iteration frequency in Hertz
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k - perturbation amount
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xi - initial value of x
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yi - initial value of y
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A linear-interpolating sound generator based on the difference
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equations:
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xn+1 = (xn + yn+1) % 2pi
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yn+1 = (yn + ksin(xn)) % 2pi
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The standard map is an area preserving map of a cylinder discovered by
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the plasma physicist Boris Chirikov.
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Vary frequency
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(audition
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(out 0 (mul (standard-l ar (mouse-x kr 20 sample-rate 0 0.1) 1 0.5 0) 0.3)))
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Mouse-controlled parameter.
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(let ((f (fdiv sample-rate 2))
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(x (mouse-x kr 0.9 4 0 0.1)))
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(audition
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(out 0 (mul (standard-l ar f x 0.5 0) 0.3))))
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As a frequency control
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(let* ((x (mouse-x kr 0.9 4 0 0.1))
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(f (mul-add (standard-l ar 40 x 0.5 0) 800 900)))
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(audition
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(out 0 (mul (sin-osc ar f 0) 0.4))))
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