exprand — Exponential distribution random number generator (positive values only).
Exponential distribution random number generator (positive values only). This is an x-class noise generator.
klambda -- reciprocal of lambda parameter for the exponential distribution.
The probablity density function of an exponential distribution is an exponential curve, whose median is log(2)/lambda. For more detailed explanation of these distributions, see:
C. Dodge - T.A. Jerse 1985. Computer music. Schirmer books. Second edition, section 11.1B4
D. Lorrain. A panoply of stochastic cannons. In C. Roads, ed. 1989. Music machine . Cambridge, Massachusetts: MIT press, pp. 351 - 379.
Here is an example of the exprand opcode. Play exprand.csd
Example 280. Example of the exprand 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 exprand.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 instr 1 ; every run time same values klamda exprand 20 printk .2, klamda ; look aout oscili 0.8, 440+klamda, 1 ; & listen outs aout, aout endin instr 2 ; every run time different values seed 0 klamda exprand 20 printk .2, klamda ; look aout oscili 0.8, 440+klamda, 1 ; & listen outs aout, aout endin </CsInstruments> <CsScore> ; sine wave f 1 0 16384 10 1 i 1 0 2 i 2 3 2 e </CsScore> </CsoundSynthesizer>
Its output should include lines like this:
i 1 time 0.00033: 4.09813 i 1 time 0.20033: 56.39567 i 1 time 0.40033: 3.23362 i 1 time 0.60033: 0.24277 i 1 time 0.80033: 13.71228 i 1 time 1.00000: 12.71885 i 1 time 1.20033: 32.36737 i 1 time 1.40033: 0.29747 i 1 time 1.60033: 4.04450 i 1 time 1.80000: 35.75676 i 1 time 2.00000: 3.69845 Seeding from current time 3034472128 i 2 time 3.00033: 6.67934 i 2 time 3.20033: 2.72431 i 2 time 3.40033: 14.51822 i 2 time 3.60000: 12.10120 i 2 time 3.80033: 1.12266 i 2 time 4.00000: 26.90772 i 2 time 4.20000: 0.43554 i 2 time 4.40033: 28.59836 i 2 time 4.60033: 27.01831 i 2 time 4.80033: 18.19911 i 2 time 5.00000: 4.45125