[Numpy-discussion] numpy.arccos(numpy.inf)????
Stuart Brorson
sdb at cloud9.net
Fri May 16 12:47:59 EDT 2008
Hi --
Sorry to be a pest with corner cases, but I found another one.
In this case, if you try to take the arccos of numpy.inf in the
context of a complex array, you get a bogus return (IMO). Like this:
In [147]: R = numpy.array([1, numpy.inf])
In [148]: numpy.arccos(R)
Warning: invalid value encountered in arccos
Out[148]: array([ 0., NaN])
In [149]: C = numpy.array([1+1j, numpy.inf])
In [150]: numpy.arccos(C)
Warning: invalid value encountered in arccos
Out[150]: array([ 0.90455689-1.06127506j, NaN -Infj])
The arccos(numpy.inf) in the context of a real array is OK, but taking
arcocs(numpy.inf) in the context of a complex array should return
NaN + NaNj, IMO.
Thoughts?
Stuart Brorson
Interactive Supercomputing, inc.
135 Beaver Street | Waltham | MA | 02452 | USA
http://www.interactivesupercomputing.com/
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