Re: Submission of Matrix Kronecker Product for calc

[Vincent Belaïche]

Dear Jay,

1) No problem if you like to tidy up. Please do as you like.

2) For the legal paper, no problem either. Please send me the form and
make me know whether I can fill it electronically, or if I need a postal
real paper send.

3) Concerning whether the result should or should not be a matrix, I am
not sure that this is 100% useful. My intent was not to add extra
useless bracketing. However the counterpart of this is that if you use
the calc-Funckron in Lisp you would may need in the sequel extra testing
in order to know into what level of bracketing it has resulted. Maybe
some extra optional argument telling whether to minimize bracketing or
not would therefore be useful.

However, not being a Lisp expert I did not know how to make this on the
Lisp function on the one hand, and have it compatible with Stack
manipulation on the other hand (in case of Stack manipulation some "C-u
+ digit" before calling function could serve telling whether bracketing
is to be minimized or not).

In fact, for my own purpose (I wanted to computed some Walsh codes by
"kron"-ing some 2x2 Hadamard matrices together) and having
systematically matrices and not vectors was sufficient.

4) note that the function name "kron" has already some publicity as it
is borrowed from Matlab and Scilab (a license-free equivalent made by
INRIA and ENPC France). So I suggest to keep the same.

BR,
Vincent.



Jay Belanger a écrit :
> Vincent Belaïche writes:
> ...
>
>> Maybe this can be useful to somebody else.
>>
>
> Yes. Would there be a problem if I tidied it up a bit?
> Altogether, it would end up 20 lines or so; to be included in Calc,
> we would need legal papers from you.
>
>
>> (defun calcFunc-kron (x y)
>> "Kronecker product of matrices x and y.
>>
>
> If x and y are not explicitly matrices, I take it they will be
> implicitly considered matrices.
>
>
>> After computation the result may be desembedded from matrix so that
>> the Kronecker product of two scalars is a scalar,
>>
> ...
>
> Why should the result not be a matrix? Is it useful?
>
> Jay
>
>
>

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