I'm using UMFPACK to solve Ax = B where both A and B are matrices. Currently in my implementation, I'm solving x(:,i) = A\b(:,i) one by one to get x. Is there a way to directly get x without having to loop through each columns of B like LAPACK does?
I'm afraid not. UMFPACK user guide p59, about umfpack_*_solve routine(s):
This routine does not solve for multiple right-hand-sides, nor does it allow b to be stored in a sparse-column form.
Also, under "Future work":
The solve routines could handle multiple right-hand sides, and sparse right-hand sides.
Which rather implies that it isn't supported presently.