Direct Sparse Solver (DSS) Interface Routines

Intel MKL supports the DSS interface, an alternative to the Intel MKL PARDISO interface for the direct sparse solver. The DSS interface implements a group of user-callable routines that are used in the step-by-step solving process and utilizes the general scheme described in Appendix A Linear Solvers Basics for solving sparse systems of linear equations. This interface also includes one routine for gathering statistics related to the solving process and an auxiliary routine for passing character strings from Fortran routines to C routines.

The DSS interface also supports the out-of-core (OOC) mode.

Table "DSS Interface Routines" lists the names of the routines and describes their general use.

DSS Interface Routines
Routine Description

Initializes the solver and creates the basic data structures necessary for the solver. This routine must be called before any other DSS routine.


Informs the solver of the locations of the non-zero elements of the matrix.


Based on the non-zero structure of the matrix, computes a permutation vector to reduce fill-in during the factoring process.

dss_factor_real, dss_factor_complex

Computes the LU, LDLT or LLT factorization of a real or complex matrix.

dss_solve_real, dss_solve_complex

Computes the solution vector for a system of equations based on the factorization computed in the previous phase.


Deletes all data structures created during the solving process.


Returns statistics about various phases of the solving process.


Passes character strings from Fortran routines to C routines.

To find a single solution vector for a single system of equations with a single right-hand side, invoke the Intel MKL DSS interface routines in this order:

  1. dss_create
  2. dss_define_structure
  3. dss_reorder
  4. dss_factor_real, dss_factor_complex
  5. dss_solve_real, dss_solve_complex
  6. dss_delete

However, in certain applications it is necessary to produce solution vectors for multiple right-hand sides for a given factorization and/or factor several matrices with the same non-zero structure. Consequently, it is sometimes necessary to invoke the Intel MKL sparse routines in an order other than that listed, which is possible using the DSS interface. The solving process is conceptually divided into six phases. Figure "Typical order for invoking DSS interface routines" indicates the typical order in which the DSS interface routines can be invoked.

Typical order for invoking DSS interface routines

Typical order for invoking DSS interface routines

See the code examples that use the DSS interface routines to solve systems of linear equations in the Intel MKL installation directory (dss_*.f and dss_*.c).

  • Fortran examples: examples/solverf/source

  • C examples: examples/solverc/source

For more complete information about compiler optimizations, see our Optimization Notice.