Re: Submission of Matrix Kronecker Product for calc

["Vincent Belaïche" <vincent.b.1@hotmail.fr>]

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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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