[SciPy-user] How to get sqrt(-1) = 1j per default?

Martin Kirsch xyz.account@arcor...
Sun Jul 12 11:22:37 CDT 2009


Robert Kern <robert.kern <at> gmail.com> writes:

> ... forgetting that the scipy namespace
> aliases the numpy functions and only use the subpackages in scipy. Use
> the functions from numpy or numpy.lib.scimath directly, as needed.
> 

Ok, using only the scipy subpackages helps to decouple the interdependencies
between numpy and scipy (many pitfalls for newcomers).
But why it makes a difference doing "from scipy import *"
(1) per ipy_profile_scipy.py (ipython -pylab -p scipy) => sqrt(-1)= NaN
(2) per console input => sqrt(-1)= 1j
?
Originally I guessed that in both cases sqrt comes from scipy because of the
preceding "from scipy import *" in both cases, but case (1) references
numpy.sqrt despite "from scipy import *" in ipy_profile_scipy.py and I don't
know the reason.





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