Hello, I tried different arcsin functions on a complex number (z=0.52+0j) and obtained the following results: cmath.asin(z) gives (0.54685095069594414+0j) #okay -1j*log(1j*z+sqrt(1-z**2)) gives (0.54685095069594414+0j) #okay, by definition numarray.arcsin(z) gives (0.54685095069594414+0j) #still okay but numpy.arcsin(z) gives (0.54685095069594414+0.54685095069594414j) #bug?? Is it really a bug in numpy, or is there another explanation? Thanks Daniel Poitras Ottawa
Daniel Poitras wrote:
Hello,
I tried different arcsin functions on a complex number (z=0.52+0j) and obtained the following results:
cmath.asin(z) gives (0.54685095069594414+0j) #okay
-1j*log(1j*z+sqrt(1-z**2)) gives (0.54685095069594414+0j) #okay, by definition
numarray.arcsin(z) gives (0.54685095069594414+0j) #still okay
but
numpy.arcsin(z) gives (0.54685095069594414+0.54685095069594414j) #bug??
Is it really a bug in numpy, or is there another explanation?
It's a bug. I seem to remember fixing this one before, but I guess it crept back in (or the bug I fixed was a similar one in another piece of code. Should be fixed in SVN now. -Travis
participants (2)
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Daniel Poitras
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Travis Oliphant