atan2 function

This function calculates the angle (or complex argument) of the argument and returns the result. The return value is always in the correct quadrant. This function is very useful for many transformations and coloring algorithms, and acts the same as the atan2 function in the C programming language library.

Here is some sample code to illustrate the behaviour of atan2:

  angle = atan2(arg)    

is equivalent to

  if real(arg) > 0    angle = atan(imag(arg) / real(arg))  elseif real(arg) == 0    if imag(arg) > 0      angle = 0.5 * #pi    else      angle = -0.5 * #pi    endif  else    if imag(arg) > 0      angle = #pi + atan(imag(arg) / real(arg))    else      angle = -#pi + atan(imag(arg) / real(arg))    endif  endif    

Examples:

  atan2((1, 1))    ; 0.25 * pi  atan2((-1, -1))  ; -0.75 * pi    

See Also
sin function
cos function
atan function

atan2 function