taninv2 — Returns an arctangent.


Returns the arctangent of iy/ix, ky/kx, or ay/ax.


ares taninv2 ay, ax
ires taninv2 iy, ix
kres taninv2 ky, kx
...taninv2(ky, kx)... (no rate restriction)

Returns the arctangent of iy/ix, ky/kx, or ay/ax. If y is zero, taninv2 returns zero regardless of the value of x. If x is zero, the return value is:

  • π/2, if y is positive.

  • -π/2, if y is negative.

  • 0, if y is 0.


iy, ix -- values to be converted


ky, kx -- control rate signals to be converted

ay, ax -- audio rate signals to be converted


Here is an example of the taninv2 opcode. It uses the file taninv2.csd.

Example 1051. Example of the taninv2 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 taninv2.wav -W ;;; for file output any platform

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

; Instrument #1.
instr 1
  ; Returns the arctangent for 1/2.
  i1 taninv2 1, 2

  print i1


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


Its output should include a line like this:

instr 1:  i1 = 0.464

See Also



Author: John ffitch
University of Bath/Codemist Ltd.
Bath, UK
April 1998

Example written by Kevin Conder.

New in Csound version 3.48

Corrected on May 2002, thanks to Istvan Varga.

Available as a function in version 6.00