Iterative linear solver for sparse array.

Hi,

I see that there is a feature request:
https://github.com/arrayfire/arrayfire/issues/2234
for the function "solve" to support sparse array. I suppose "solve" function would use a direct solver.

I also see that there is a feature request for an iterative linear solver:
https://github.com/arrayfire/arrayfire/issues/1568
I suppose this request is for dense array.

It would be nice if there was a way to solve linear systems using sparse array and iterative solvers. In fact, any linear solver for sparse array could be useful. I'm just adding this specific request as I think it is not in any feature request.

Thanks