PETSC_EXTERN_TYPEDEF typedef PetscErrorCode(DSNEPMatrixFunctionFn)(DS ds,PetscScalar lambda,PetscBool deriv,DSMatType mat,void *ctx);
| ds | - the direct solver object | |
| lambda | - point where T(lambda) or T'(lambda) must be evaluated | |
| deriv | - if true compute T'(lambda), otherwise compute T(lambda) | |
| mat | - the DS matrix where the result must be stored | |
| ctx | - [optional] user-defined context for private data for the matrix evaluation routine (may be `NULL`) |