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Topic: Kronecker product reversal, or division
Replies: 1   Last Post: Feb 7, 2013 5:34 PM

 Ray Koopman Posts: 3,383 Registered: 12/7/04
Re: Kronecker product reversal, or division
Posted: Feb 7, 2013 5:34 PM

On Feb 7, 12:54 pm, carolinebal...@gmail.com wrote:
> I have a Kronecker product (A) of an unknown (B) and a known (A) matrix: A = B ? C. Again, A and C are known - I wish to calculate B. Incidentally, C is an identity matrix times a known constant.
>
> Is it possible to recover B?
>
> If so, does anyone have a bit of code to do this? (I write in IDL.)
>
> Thanks,
> Caroline

If B is 4 x 2 and C is 3 x 3 then A should look like this:

b11*c 0 0 b12*c 0 0
0 b11*c 0 0 b12*c 0
0 0 b11*c 0 0 b12*c
b21*c 0 0 b22*c 0 0
0 b21*c 0 0 b22*c 0
0 0 b21*c 0 0 b22*c
b31*c 0 0 b32*c 0 0
0 b31*c 0 0 b32*c 0
0 0 b31*c 0 0 b32*c
b41*c 0 0 b42*c 0 0
0 b41*c 0 0 b42*c 0
0 0 b41*c 0 0 b42*c

Just divide by c. You should get 3 copies of each element of B.