Subject: What is wrong in multiplication of matrices
From: Rupert Swarbrick
Date: Tue, 20 Jul 2010 15:20:33 +0100
Zbigniew Komarnicki <cblasius at gmail.com> writes:
> I see that in the multiplication were used operator * but I declare that
> A,C,P,Q are nonscalars and it should use the . operator. Why it is not done?
> Or how I can multiply matrices as block matrices? I want only operate on
> symbolic matrices as A,C,P,Q not as real i.e.
I think you want to change the variable matrix_element_mult (section
25.2 of the manual).
> A: matrix([1,2],[3,4]) <---- not on such matrices, where are values
>
> I want to work on symbolic matrices. Is maybe any chance to introduce in
> future versions of maxima something such as:
>
> declare([A,C,P,Q], symbolic_matrix)
>
> to tell maxima that I operate on matrices in symbolic way?
>
> I also want to ask how to simplify r1[1,1]
> -P*(P^^(-1))^2
>
> it should simplify to
> -P
>
> but there is * not . so it couldn't simplify.
>
> When I write with . it also do not simplify, why?
> -P . (P^^(-1))^2
> I got:
> <- 1> 2
> - P . (P )
>
> But when I write
> -P . P^^(-1);
> then I got correct results:
> - 1
I can't check now, but this might be related to the do<stuff> flags that
are defined on the same page of the manual as matrix_element_mult.
Rupert
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