On Saturday, January 4, 2014 2:21:29 AM UTC+1, Thierry (sage-googlesucks@xxx)
wrote:
>
> On my Sage 6.0, i first get a warning (according to
> http://sourceforge.net/projects/numpy/files/NumPy/1.5.0/NOTES.txt/view
> the message comes from numpy):
> sage: 1j / np.float64(2)
>
> /opt/sagemath/sage-6.0-i686-Linux/src/bin/sage-ipython:1:
> ComplexWarning: Casting complex values to real discards the imaginary
> part
> #!/usr/bin/env python
> 0.0
>
> So, this is not really a bug ;)
Issuing a warning doesn't make the result more correct. So in my eyes it is a
bug. Actually, I don't see why a complex value should be casted to real in the
process of the calculation above. Perhaps a real value could be casted to
complex but not the other way round.
Note also, that the problem does not occur in a python only environment
(python/numpy without Sage):
>>> import numpy as np
>>> 1j / np.float64(2)
0.5j
Cheers,
Bernhard
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