Re: load sparse matrix from matlab hdf5 file

[Martin Helm]

Am Donnerstag, den 31.03.2011, 18:41 +0200 schrieb Christian Fischer: 
> Hi
> 
> I want to load a sparse matrix from hdf5 file created by matlab.
> I ended up with a struct like:
> 
> octave3.3.54:3> a
> a =
> {
>   data =
> 
>      1   2   3
> 
>   ir =
> 
>     0  1  2
> 
>   jc =
> 
>     0  1  2  3
> 
> }
> 
> Is it possible to load the matrix as sparse matrix? Or is there a quick way to
> convert the struct into a sparse matrix in octave.
> 
> Thank you for your help
> Christian
> 

This is most probably compressed column storage with zero based indexes,
but to be sure can you post the output from a bit more complex matrix to
identify it really.

In matlab create sparse(magic(4)) export that and show the output after
export to hdf5 and input into octave.

I do not have matlab so I cannot check it myself.

Assuming it is ccs something like that should do:

        n = length(a.jc)-1;
        ii = repelems(1:n, [1:n; diff(a.jc)]);
        mat = sparse(a.ir+1, ii, a.data);

mat should now contain the correct sparse matrix, but please check that
with some tests.