[SciPy-user] casting complex numbers

Travis Oliphant oliphant.travis at ieee.org
Fri Feb 17 00:55:33 CST 2006

Ryan Krauss wrote:

>Is there a way to make python return a complex number number instead
>of nan when taking the sqrt of a negative float?  I have an
>automatically generated function based on Maxima symbolic output that
>is giving bad output because of this.  Basically, part of the symoblic
>expression includes sqrt(-s**2*x) where s is complex and this
>expression would evaluate nicely in python.  For whatever reason,
>Maxima prefers to output this expression as sqrt(-x)*s, which would
>also evaluate correctly if sqrt(-x) gave 1.0j*sqrt(x), but since x is
>a float it is returning nan.  I am hoping for flag similar to from
>__future__ import division instead of having to declare all my
>variables as complex.
import numpy.lib.scimath as nls



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