[SciPy-dev] Numpy example for arctan2 perhaps wrong/misleading/confusing?

Samuel John scipy@SamuelJohn...
Mon Jun 9 07:30:00 CDT 2008


Hi all,

the page

http://www.scipy.org/Numpy_Example_List_With_Doc#head-ad8dc60988f26f59ebe565e4af24dc95fcb8a7e9

describes the numpy.arctan2 function and gives an example:

> arctan2(array([0, 1]), array([1, 0]))

However in the example there are used two arrays as arguments to
arctan2, where it should probably be the x and y component of a single
2D vector. What arctan2(x,y) returns is the angle between the 2D
vector (x,y) and the x axis. The example made me assume that it can
compute the angle between two vectors, which it does obviously not.

Wikipedia has a nice article on atan2. I think arctan2 works the same, or?
http://en.wikipedia.org/wiki/Atan2

What could be the reason of using arrays in arctan2? Could someone
update the documentation?
Also help(numpy.arctan2) is not very helpful, to be honest.

cheers,
 Samuel


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