Tim Wesserman or Edward Shore

[Thomas Klemm]

(03-15-2019 10:44 PM)mathnovice Wrote:  I need to extend the function atan2(y,x).

Not sure if this helps, but you can emulate atan2:

\(atan2(y, x) = 2 \arctan \frac{y}{r+x}\) where \(r=\sqrt{x^2+y^2}\)

In Python:

Code:

from math import pi, sqrt, atan

def atan2(y, x):
    r = sqrt(x*x + y*y)
    return 0.0 if r == 0.0 else pi if r + x == 0.0 else 2 * atan(y / (r + x))

Code:

>>> atan2(0, 0)
0.0

>>> atan2(0, 3)
0.0

>>> atan2(0, -3)
3.141592653589793

>>> atan2(2, 3)
0.5880026035475675

>>> atan2(-2, 3)
-0.5880026035475675

>>> atan2(2, -3)
2.5535900500422257

>>> atan2(-2, -3)
-2.5535900500422257

Quote:It is in FORTRAN and I have no idea about that.

Me neither.

Cheers
Thomas