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-   -   Re: Matrix operations on character matrix element? (http://www.velocityreviews.com/forums/t678228-re-matrix-operations-on-character-matrix-element.html)

 Robert Kern 04-02-2009 12:27 AM

Re: Matrix operations on character matrix element?

On 2009-04-01 19:12, Terry Reedy wrote:
> olusina eric wrote:
>> I hope somebody will be able to help me here.
>> I am trying to solve some physical problems that will require the
>> generation of some function in terms of some parameters. These
>> functions are derived from matrix operation on “characters”. Are there
>> ways numpy/scipy perform matrix operations on characters?
>>
>> For example A = matrix([[a, b,c],[d,e,f],[1,2,3]])
>> B = matrix([[g,h,4],[I,j,5],[k,l,6]])

>
> A to l are identifiers, not characters, and must be bound to objects for
> the above to make any sense. Did you mean 'a' to 'l'?
>
>> Is it possible to perform operations like A*B or A+B
>>
>> And most especially: linalg.solve(A,eye(3,3))

>
> If you mean, operate on symbols to do symbolic computation, the same way
> one might with paper and pencil, the simple answer is no. Numpy is not a
> computer algebra system.
>
> Computer algebra requires that one define classes such as Symbol, with
> all the usual arithmetic operations. I am not sure whether numpy
> algorithms can work on arrays of instances of user-defined classes such
> as this.

They can't.

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma