log — Returns a natural log of a number, or an array (with optional arbitrary base).


Returns the natural log of x (x positive only). In the case of an array input, the operation can have an optional arbitrary base.

The argument value is restricted for log, log10, and sqrt.


log(x) (no rate
log(k/i[]) (k- or i-arrays )
kout[]log kin[],ibas

where the argument within the parentheses may be an expression. Value converters perform arithmetic translation from units of one kind to units of another. The result can then be a term in a further expression. In the case of an array input, ibas is the optional arbitrary base, which defaults to e (natural log base).


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

Example 540. Example of the log 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 log.wav -W ;;; for file output any platform

; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1

; Instrument #1.
instr 1
  i1 = log(8)
  print i1


; Play Instrument #1 for one second.
i 1 0 1


Its output should include a line like this:

instr 1:  i1 = 2.079

See also

Mathematical Functions


Written by John ffitch.

New in version 3.47

Example written by Kevin Conder.