atan2

Purpose

Computes an angle from an x, y coordinate.

Format

z = atan2(y, x)
Parameters:
  • y (matrix) – NxK matrix or P-dimensional array where the last two dimensions are NxK, the y coordinate.
  • x (matrix) – LxM matrix or P-dimensional array where the last two dimensions are LxM, ExE conformable with y, the x coordinate.
Returns:

z (matrix) – max(N,L) by max(K,M) matrix or P-dimensional array where the last two dimensions are max(N,L) by max(K,M).

Examples

// Create the sequence -π, -π/2, 0, π/2, π
x = seqa(-pi, pi/2, 5);
y = 1;

zpol = atan2(y, x);
zdeg = zpol*(180/pi);

print "x = " x;
print "zpol = " zpol;
print "zdeg = " zdeg;

After the code above:

   -3.142         2.833         162.343
   -1.571         2.575         147.518
x = 0.000  zpol = 1.571  zdeg =  90.000
    1.571         0.567          32.482
    3.142         0.308          17.657

Remarks

Given a point x, y in a Cartesian coordinate system, atan2() will give the correct angle with respect to the positive x-axis. The answer will be in radians from \(-\pi\) to \(+\pi\).

To convert radians to degrees, multiply by \(180/π\).

atan2() operates only on the real component of x, even if x is complex.

See also

Functions atan(), sin(), cos(), pi(), tan(), arcsin(), arccos()