Dear karthiksrao,

It is a good question. Let me say more before answer it :).
MKL provide BLAS and LAPACK., where BLAS for general vector and matrix operation and LAPACK is for solving systems of linear equations and performing a number of related computational tasks.
The function mkl_zcsrsm is for solves a system of linear matrix equations for a sparse matrix in the CSR format,
and it is corresponding function ?trsm, Solves a matrix equation (one matrix operand is triangular).
Both are for solve a system of linear matrix, you may ask why they are not in LAPACK, but in BLAS domain and sparse BLAS Level 2 and Level 3 Routines (matrix-vector and matrix-matrix operations)

You may figure out the answer yourself: only special linear system which have matrix like upper triangle or upper or lower triangular matrix, you can use simple operation like marix to vector or marix to matrix to solve it.
Otherwise, you need to use the driver routine or computation routines like LU descompose etc to solve the linear system.

So as you see, it is impossible to extend it directly. You may look for the domain like the sparse solver Routines or convert the Sparse matrix to General matrix, then use Lapack function to solve a linear equation with a general unsymmetric sparse matrix.

You may reference some docs like Appendix A: Linear Solvers Basics in MKL reference manual and c/fortran code example in there or in MKL install directory.

Best Regards,
Ying

Dear Kathirksrao,

Input matrix for mkl_zcsrsm can be general. The value of matdescra(1)-matdescra(3) indicates which triangle should be used and MKL Sparse BLAS triangular solvers automatically exctract the needed triangle.. Please look art the section "Interface consideration" in chapter "Sparse BLAS level 2 and level 3" in the MKL Reference Manual. The Table "Possible Combinations of Element Values of the Parameter matdescra" lists all possible combinations of element values for of matdescra both multiplication routines and triangular solvers.

Sergey