What does the means of struct matrix_descr in mol_sparse_XXX routines?

Hi all,

    In many mkl_sparse_XXX routines (version 11.3), there is a a parameter of type matrix_descr, just like :

sparse_status_t mkl_sparse_s_trsv (sparse_operation_t operation, float alpha, const sparse_matrix_t A, struct matrix_descr descr, const float *x, float *y);

The explanation of this parameter in manual is:

descr : Structure specifying sparse matrix properties. ......But it is confusing. Following is the code snippet in MKL example sparse_trsv.c,
 
 

   //*******************************************************************************
    //     Declaration and initialization of parameters for sparse representation of
    //     the matrix A in the compressed sparse row format:
    //*******************************************************************************
#define M 5
#define N 5
#define NNZ 13
    //*******************************************************************************
    //    Sparse representation of the matrix A
    //*******************************************************************************
    double csrVal[NNZ]    = { 1.0, -1.0,     -3.0,
                             -2.0,  5.0,
                                         4.0, 6.0, 4.0,
                             -4.0,       2.0, 7.0,
                                    8.0,          -5.0 };
    MKL_INT    csrColInd[NNZ] = { 0,      1,        3,
                              0,      1,
                                           2,   3,   4,
                              0,           2,   3,
                                      1,             4 };
    MKL_INT    csrRowPtr[M+1] = { 0, 3, 5, 8, 11, 13 };
    // Descriptor of main sparse matrix properties
    struct matrix_descr descrA;
    // Structure with sparse matrix stored in CSR format
    sparse_matrix_t       csrA;

......

    // Create matrix descriptor
    descrA.type = SPARSE_MATRIX_TYPE_TRIANGULAR;
    descrA.mode = SPARSE_FILL_MODE_LOWER;
    descrA.diag = SPARSE_DIAG_UNIT;

    // Compute y = alpha * A^{-1} * x
    mkl_sparse_d_trsv ( SPARSE_OPERATION_NON_TRANSPOSE,
                        alpha,
                        csrA,
                        descrA,
                        x,
                        y );

Obviously, the matrix csrA is not a triangular matrix, and the diagnoal is not unit. Why set the properties of descrA to TRIANGULAR and DIAG_UNIT?
If I change the properties to other option, for example:
     

    descrA.type = SPARSE_MATRIX_TYPE_GENERAL;
    descrA.diag = SPARSE_DIAG_NON_UNIT;

Now it can not get correct result. 

How to setting the properties of matrix_descr correctly?

Best regards,

Tianxiong Lu