Re: Help with [] for defined types

[Paul Kienzle]

On Jul 27, 2004, at 6:57 PM, David Bateman wrote:

> QUESTION 3
> ----------
>
> The load_binary and save_binary functions are for the octave binary
> format (i.e. save -binary ) and have nothing to do with the
> -mat-binary format. We have no control over the Matlab file formats
> and so there is no way to extend them and thus splitting their 
> functioning
> into the octave_value as was done for the ascii, binary and hdf5 
> formats
> makes less sense. This might be done however, with new save_mat_ascii,
> save_mat4_binary and save_mat5_binary methods of the octave_value 
> class.
> But my feeling is that is pretty ugly.
>
> So unfortunately as it stands unless sparse actually goes into octave
> you'll have difficulties using the -mat-binary or even -mat-ascii
> formats.  You should be able to use an HDF5 format to exchange data
> with matlab however.

I've considered adding sparse support to mex by calling the
functions "spfind" to get the matrix out of the octave value and
"sparse" to put the matrix back into a sparse value.  You could
do something similar in load/save for the matlab binary type.
Until octave has a sparse type of its own it can include fake
sparse m-files for these two functions which save the result
in full matrices.  If octave-forge is present, then it will pick up
Andy's version of the functions.  I guess you will also need
"issparse" to detect whether the matrix type is a sparse matrix
before storing it.

- Paul