Tim Wesserman or Edward Shore
03-17-2019, 02:59 AM (This post was last modified: 03-17-2019 03:08 AM by toml_12953.)
Post: #9
 toml_12953 Senior Member Posts: 1,889 Joined: Dec 2013
RE: Tim Wesserman or Edward Shore
(03-16-2019 02:20 AM)Thomas Klemm Wrote:
(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

I get the same answers with ARG(Y+X) without having to write a function.

Code:
>>> ARG(0+0i) 0.0 >>> ARG(3+0i) 0.0 >>> ARG(-3+0i) 3.141592653589793 >>> ARG(3+2i) 0.5880026035475675 >>> ARG(3-2i) -0.5880026035475675 >>> ARG(-3+2i) 2.5535900500422257 >>> ARG(-3-2i) -2.5535900500422257

Tom L
Cui bono?
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 Messages In This Thread Tim Wesserman or Edward Shore - mathnovice - 03-15-2019, 10:44 PM RE: Tim Wesserman or Edward Shore - chromos - 03-15-2019, 11:09 PM RE: Tim Wesserman or Edward Shore - Thomas Klemm - 03-16-2019, 02:20 AM RE: Tim Wesserman or Edward Shore - toml_12953 - 03-17-2019 02:59 AM RE: Tim Wesserman or Edward Shore - ijabbott - 03-16-2019, 08:59 AM RE: Tim Wesserman or Edward Shore - JMB - 03-16-2019, 01:49 PM RE: Tim Wesserman or Edward Shore - Albert Chan - 03-16-2019, 09:11 PM RE: Tim Wesserman or Edward Shore - mathnovice - 03-16-2019, 03:39 PM RE: Tim Wesserman or Edward Shore - SammysHP - 03-16-2019, 06:25 PM

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