As Jordi said, it is unlikely that Octave will add a sparse-single type.  Although it is a "fixed" Matlab, it shouldn't become bloated.

What type should sparse*single return?  If the single is a scalar, then I suppose a sparse is best, but if the single is a matrix, then I suppose a single matrix is best.  Is that right?

OK thanks for the info Jordi. I spent some time looking in sparse.cc and MSparse.cc

http://octave.sourceforge.net/doxygen41/d2/dc3/sparse_8cc_source.html

http://octave.sourceforge.net/doxygen41/d7/d5b/MSparse_8cc_source.html

and saw the latter is templated so I wondered if it was a simple change. BTW is this fall-back code if SuiteSparse is not used?


Also, interesting about single*sparse. I had to check it out - unfortunately it looks like it has the same limitation.

x'*A

error: binary operator '*' not implemented for 'float matrix' by 'sparse matrix' operations

I would like to request thoughts on implementing sparse single matrices. The main reason would be so that addition and multiply can be performed on non-sparse single matrices and vectors. E.g.

 A = sparse(randn(10));
 x = randn(10,1,"single");
 b = A*x;

error: binary operator '*' not implemented for 'sparse matrix' by 'float matrix' operations

I have an application that uses a sparse matrix multiply in amongst other operations (FFT, dense multiplies, etc.) and it all has to be done in doubles because of the sparse operator. The data comes in as 16-bit ints so single precision is plenty.