# [Matrix-SIG] Power of trigs

**Paul F. Dubois
**
Paul F. Dubois" <dubois1@llnl.gov

*Thu, 19 Mar 1998 07:25:51 -0800*

Complex literals are of the form n.nnnn j. In this case, Numeric needs you
to help it know that you want a complex power.
>>>* import Numeric
*>>>* Numeric.power(2., .5)
*1.41421356237
>>>* Numeric.power(-2.0, .5)
*Traceback (innermost last):
File "<stdin>", line 1, in ?
ValueError: math domain error
>>>* Numeric.power(-2.0+0j, .5)
*(8.65927457072e-017+1.41421356237j)
>>>*
*
-----Original Message-----
From: Dave Stinchcombe <dars@soton.ac.uk>
To: matrix-sig@python.org <matrix-sig@python.org>
Date: Thursday, March 19, 1998 3:48 AM
Subject: [Matrix-SIG] Power of trigs
>*Hi again,
*>*This morning I needed to write a quick and easy root finder, so obviously I
*>*grabbed Numeric Python.
*>*
*>*I have a problem though. I wrote the line:
*>*Numeric.power(Numeric.cos(phi),1-2*nus)
*>*
*>*where nus is a constant of 0.3. phi is an array holding a list of values
*>*I'm searching through. The problem comes that this line fails when phi is
*>*greater than pi/2.
*>*
*>*Now obviously this is due to the fact I'm trying to calculate a complex (or
*>*at the very least an imaginary) number. But I want to. Can any one give
*>*some suggestions as to how to cope, or in some way make python also believe
*>*in complex numbers.
*>*
*>*Yours
*>*Dave
*>*
*>*
*>*
*>*------------------------------------------------------
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*>*
*