vrandi — Generate a sort of 'vectorial band-limited noise'
ifn - number of the table where the vectorial signal will be generated
ielements - number of elements to process
idstoffset - (optional, default=0) -- index offset for the destination table
iseed (optional, default=0.5) -- seed value for the recursive pseudo-random formula. A value between 0 and +1 will produce an initial output of kamp * iseed. A negative value will cause seed re-initialization to be skipped. A value greater than 1 will seed from system time, this is the best option to generate a different random sequence for each run.
isize (optional, default=0) -- if zero, a 16 bit number is generated. If non-zero, a 31-bit random number is generated. Default is 0.
ioffset - (optional, default=0) -- a base value added to the random result.
krange - range of random elements (from -krange to krange)
kcps - rate of generated elements in cycles per seconds
This opcode is similar to randi, but operates on vectors instead of with scalar values.
Though argument isize defaults to 0, thus using a 16-bit random number generator, using the newer 31-bit algorithm is recommended, as this will produce a random sequence with a longer period (more random numbers before the sequence starts repeating).
The output is a vector contained in ifn (that must be previously allocated).
All these operators are designed to be used together with other opocdes that operate with vector such as bmscan, adsynt etc.
Note: bmscan not yet available on Canonical Csound
Here is an example of the vrandi opcode. It uses the file vrandi.csd.
Example 508. Example of the vrandi 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 ; Audio out Audio in No messages -odac -iadc -d ;;;RT audio I/O ; For Non-realtime ouput leave only the line below: ; -o vrandi.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr=44100 ksmps=128 nchnls=2 ;Example by Andres Cabrera gitab ftgen 0, 0, 16, -7, 0, 128, 0 instr 1 krange init p4 kcps init p5 ioffset init p6 ; table krange kcps ielements idstoffset iseed isize ioffset vrandi gitab, krange, kcps, 3, 3, 2, 1, ioffset kfreq1 table 3, gitab kfreq2 table 4, gitab kfreq3 table 5, gitab ;Change the frequency of three oscillators according to the random values aosc1 oscili 4000, kfreq1, 1 aosc2 oscili 2000, kfreq2, 1 aosc3 oscili 4000, kfreq3, 1 outs aosc1+aosc2, aosc3+aosc2 endin </CsInstruments> <CsScore> f 1 0 2048 10 1 ; krange kcps ioffset i 1 0 5 100 1 300 i 1 5 5 5 1 400 i 1 10 5 100 2 1000 i 1 15 5 400 4 1000 i 1 20 5 1000 8 2000 i 1 20 5 300 32 350 e </CsScore> </CsoundSynthesizer>