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matrix class

DarrenWeber Darren.Weber at radiology.ucsf.edu
Tue Jun 12 21:56:52 EDT 2007 
On Jun 12, 6:20 pm, Dan Bishop <danb... at yahoo.com> wrote:
> On Jun 12, 7:31 pm, DarrenWeber <Darren.We... at radiology.ucsf.edu>
> wrote:
>
>
>
> > Below is a module (matrix.py) with a class to implement some basic
> > matrix operations on a 2D list.  Some things puzzle me about the best
> > way to do this (please don't refer to scipy, numpy and numeric because
> > this is a personal programming exercise for me in creating an
> > operational class in pure python for some *basic* matrix operations).
>
> > 1.  Please take a look at the __init__ function and comment on the
> > initialization of the list data with respect to unique memory
> > allocation.
>
> > 2.  In the operator overloading of __add__, __sub__, etc., the
> > statement isinstance(q, Matrix) raises exceptions every time.  This
> > statement works fine outside of the class definition, but not during
> > the operator evaluation.  What is going here?
> ...
>
> >     def __add__(self, q):
> >         'matrix addition: m3 = m1 + m2'
> > #         if isinstance(q, Matrix):
> > #             arg = ("q is not a matrix instance", q)
> > #             raise TypeError, arg
>
> Wouldn't it make more sense to raise an exception if q is NOT an
> instance of Matrix?


Duh, yea!  I don't recommend programming and sleep deprivation ;-)
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