need help inverting DerivVar array (Numpy/Scientific Python Q uestion)

PoulsenL at capecon.com PoulsenL at capecon.com
Wed Jun 6 16:55:38 CEST 2001


Scientific provides a derivable object which can be operated upon.  The
problem is that it does not implement an invert method and I was wondering
if there was a workaround.

-----Original Message-----
From: Robin Becker [mailto:robin at jessikat.fsnet.co.uk] 
Sent: Wednesday, June 06, 2001 5:21 AM
To: python-list at python.org
Subject: Re: need help inverting DerivVar array (Numpy/Scientific Python
Quest ion)

In article <mailman.991779129.1056.python-list at python.org>,
PoulsenL at capecon.com writes
>

Are you trying to differentiate the inverse of a matrix? What are
DerivVars?

>    I am having trouble inverting an array of DerivVar objects.  Here is 
>    the code and error:
>
>     
>
>    >>> a = 
>
Numeric.array([[DerivVar(-2.5,0,1),DerivVar(.45,1,1)],[DerivVar(5.5,2,1),Der
ivVar(-4.5,3,1)]])
>
>    >>> Numeric.sum(a)
>
>    array([(3.0, [1, 0, 1]) , (-4.0499999999999998, [0, 1, 0, 1]) 
>    ],'O')
>
>    >>> Numeric.invert(a)
>
>    Traceback (most recent call last):
>
>      File "<interactive input>", line 1, in ?
>
>    AttributeError: DerivVar instance has no attribute '__invert__'
>
>     
>
>    Any help would be greatly appreciated.
>
>     
>
>    Thanks, 
>
>     
>
>    Loren Poulsen

-- 
Robin Becker
-- 
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