vexp — Performs power-of operations between a vector and a scalar


Performs power-of operations between a vector and a scalar


vexp  ifn, kval, kelements [, kdstoffset] [, kverbose]


ifn - number of the table hosting the vectorial signal to be processed


kval - scalar operand to be processed

kelements - number of elements of the vector

kdstoffset - index offset for the destination table (Optional, default = 0)

kverbose - Selects whether or not warnings are printed (Default=0)

vexp rises kval to each element contained in a vector from table ifn,starting from table index kdstoffset. This enables you to process a specific section of a table by specifying the offset and the number of elements to be processed. Offset is counted starting from 0, so if no offset is specified (or set to 0), the table will be modified from the beginning.

Note that this opcode runs at k-rate so the value of kval is processed every control period. Use with care or you will end up with very large (or small) numbers (or use vexp_i).

These opcodes (vadd, vmult, vpow and vexp) perform numeric operations between a vectorial control signal (hosted by the table ifn), and a scalar signal (kval). Result is a new vector that overrides old values of ifn. All these opcodes work at k-rate.

Negative values for kdstoffset are valid. Elements from the vector that are outside the table, will be discarded, and they will not wrap around the table.

If the optional kverbose argument is different to 0, the opcode will print warning messages every k-pass if table lengths are exceeded.

In all these opcodes, the resulting vectors are stored in ifn, overriding the intial vectors. If you want to keep initial vector, use vcopy or vcopy_i to copy it in another table. All these operators are designed to be used together with other opcodes that operate with vectorial signals such as vcella, adsynt, adsynt2, etc. They can also be useful in conjunction with the spectral opcodes pvsftw and pvsftr.

[Note] Note

Please note that the elements argument has changed in version 5.03 from i-rate to k-rate. This will change the opcode's behavior in the unusual cases where the i-rate variable ielements is changed inside the instrument, for example in:

    instr 1
ielements  =        10
           vadd     1, 1, ielements
ielements  =        20
           vadd     2, 1, ielements


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

Example 1203. Example of the vexp opcode.

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

; Select audio/midi flags here according to platform
; Audio out   Audio in
-odac           -iadc     ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o cigoto.wav -W ;;; for file output any platform


	instr 1
ifn1 = p4
ival = p5
ielements = p6
idstoffset = p7
kval init 25
vexp ifn1, ival, ielements, idstoffset, 1

	instr 2	;Printtable
itable = p4
isize = ftlen(itable)
kcount init 0
kval table kcount, itable
printk2 kval

if (kcount == isize) then

kcount = kcount + 1 



f 1 0 16 -7 1 16 17

i2	0.0	0.2	1
i1	0.4	0.01	1	2	3	4
i2	0.8	0.2	1
i1	1.0	0.01	1	0.5	5	-3
i2	1.2	0.2	1
i1	1.4	0.01	1	1.5	10	12
i2	1.6	0.2	1



See also

Operations Vectorial/Scalar Signal


Written by Gabriel Maldonado. Optional arguments added by Andres Cabrera and Istvan Varga.

New in Csound 5 (Previously available only on CsoundAV)