urd

urd — A discrete user-defined-distribution random generator that can be used as a function.

Description

A discrete user-defined-distribution random generator that can be used as a function.

Syntax

aout = urd(ktableNum)
iout = urd(itableNum)
kout = urd(ktableNum)

Initialization

itableNum -- number of table containing the random-distribution function. Such table is generated by the user. See GEN40, GEN41, and GEN42. The table length does not need to be a power of 2

Performance

ktableNum -- number of table containing the random-distribution function. Such table is generated by the user. See GEN40, GEN41, and GEN42. The table length does not need to be a power of 2

urd is the same opcode as duserrnd, but can be used in function fashion.

For a tutorial about random distribution histograms and functions see:

  • D. Lorrain. "A panoply of stochastic cannons". In C. Roads, ed. 1989. Music machine. Cambridge, Massachusetts: MIT press, pp. 351 - 379.

Examples

Here is an example of the urd opcode. It uses the file urd.csd.

Example 934. Example of the urd opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac   ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o urd.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr 1 

ktab  = 1			;ftable 1
kurd  = urd(ktab) 
ktrig metro 5			;triggers 5 times per second
kres  samphold kurd, ktrig	;sample and hold value of kurd
      printk2 kres		;print it
asig  poscil .5, 220+kres, 2
      outs asig, asig
endin

instr 2

seed 0	;every run new values

ktab  = 1 			;ftable 1
kurd  = urd(ktab) 
ktrig metro 5			;triggers 5 times per second
kres  samphold kurd, ktrig	;sample and hold value of kurd
      printk2 kres		;print it
asig  poscil .5, 220+kres, 2
      outs asig, asig

endin
</CsInstruments>
<CsScore>
f1 0 -20 -42  10 20 .3 100 200 .7 ;30% choose between 10 and 20 and 70% between 100 and 200
f2 0 8192 10 1			  ;sine wave

i 1 0 5
i 2 6 5
e
</CsScore>
</CsoundSynthesizer>


Its output should include lines like these:

 i1   184.61538
 i1   130.76923
 i1   169.23077
 i1    12.00000
.......

WARNING: Seeding from current time 3751086165

 i2   138.46154
 i2    12.00000
 i2   123.07692
 i2   161.53846
 i2   123.07692
 i2   153.84615
......
      

See Also

cuserrnd, duserrnd

Credits

Author: Gabriel Maldonado

New in Version 4.16