kml_sparse_?csrsv

Solve a system of equations for a triangular sparse matrix that is stored in the CSR format. The operation is defined as follows:

A * y = alpha * x or A^T * y = alpha * x or A^H * y = alpha * x

x and y are vectors, and A is a sparse matrix (m x m) in the CSR format.

Interface Definition

C interface:

kml_sparse_status_t kml_sparse_scsrsv(const kml_sparse_operation_t opt, const KML_INT m, const float alpha, const char *matdescra, const float *val, const KML_INT *indx,

const KML_INT *pntrb, const KML_INT *pntre, const float *x, float *y);

kml_sparse_status_t kml_sparse_dcsrsv(const kml_sparse_operation_t opt, const KML_INT m, const double alpha, const char *matdescra, const double *val, const KML_INT *indx, const KML_INT *pntrb, const KML_INT *pntre, const double *x, double *y);

kml_sparse_status_t kml_sparse_ccsrsv(const kml_sparse_operation_t opt, const KML_INT m, const KML_Complex8 alpha, const char *matdescra, const KML_Complex8 *val, const KML_INT *indx, const KML_INT *pntrb, const KML_INT *pntre, const KML_Complex8 *x, KML_Complex8 *y);

kml_sparse_status_t kml_sparse_zcsrsv(const kml_sparse_operation_t opt, const KML_INT m, const KML_Complex16 alpha, const char *matdescra, const KML_Complex16 *val,

const KML_INT *indx, const KML_INT *pntrb, const KML_INT *pntre, const KML_Complex16 *x, KML_Complex16 *y);

Fortran interface:

RES = KML_SPARSE_SCSRSV(OPT, M, ALPHA, MATDESCRA, VAL, INDX, PNTRB, PNTRE, X, Y);

RES = KML_SPARSE_DCSRSV(OPT, M, ALPHA, MATDESCRA, VAL, INDX, PNTRB, PNTRE, X, Y);

RES = KML_SPARSE_CCSRSV(OPT, M, ALPHA, MATDESCRA, VAL, INDX, PNTRB, PNTRE, X, Y);

RES = KML_SPARSE_ZCSRSV(OPT, M, ALPHA, MATDESCRA, VAL, INDX, PNTRB, PNTRE, X, Y);

Parameters

Parameter	Type	Description	Input/Output
opt	Enumeration type kml_sparse_operation_t	Operation on matrix A. If opt=KML_SPARSE_OPERATION_NON_TRANSPOSE, then A * y = alpha * x. If opt=KML_SPARSE_OPERATION_TRANSPOSE, then A^T * y = alpha * x. If opt=KML_SPARSE_OPERATION_CONJUGATE_TRANSPOSE, then A^H * y = alpha * x.	Input
m	Integer	Number of rows in matrix A. The value range is [1, MAX_MAL_INT].	Input
alpha	For scsrsv, alpha is of the single-precision floating-point type. For dcsrsv, alpha is of the double-precision floating-point type. For ccsrsv, alpha is a single-precision complex number. For zcsrsv, alpha is a double-precision complex number.	Coefficient	Input
matdescra	Char pointer	Matrix operation attribute. For details, see the description of matdescra.	Input
val	For scsrsv, val is a single-precision floating-point array. For dcsrsv, val is a double-precision floating-point array. For ccsrsv, val is a single-precision complex array. For zcsrsv, val is a double-precision complex array.	Non-zero elements in matrix A	Input
indx	Integer array	indx[i] indicates the column number of the ith element of the val array in matrix A.	Input
pntrb	Integer array	Array of length m, containing row indices of matrix A. pntrb[i] - pntrb[0] indicates the subscript of the first non-zero element in row i in the val and indx arrays.	Input
pntre	Integer array	Array of length m, containing row indices of matrix A. pntre[i] - pntrb[0]-1 indicates the subscript of the last non-zero element in row i in the val and indx arrays.	Input
x	For scsrsv, x is a single-precision floating-point array. For dcsrsv, x is a double-precision floating-point array. For ccsrsv, x is a single-precision complex array. For zcsrsv, x is a double-precision complex array.	Vector x	Input
y	For scsrsv, y is a single-precision floating-point array. For dcsrsv, y is a double-precision floating-point array. For ccsrsv, y is a single-precision complex array. For zcsrsv, y is a double-precision complex array.	Vector y. This parameter is output after update.	Input/Output

The function does not verify the integrity of parameters. Ensure that the elements in pntrb and pntre do not exceed the maximum index value of the input matrix.

Return Value

Function execution status. The enumeration type is kml_sparse_status_t.

Dependencies

C: "kspblas.h"

Fortran: "kspblas.f03"

Examples

C interface:

    kml_sparse_operation_t opt = KML_SPARSE_OPERATION_NON_TRANSPOSE; 
    KML_INT m = 4; 
    float alpha = 1.0; 
    char *matdescra = "TLNF"; // General matrix with one-based indexing
    float val[9] = {2, -3, 7, 1, -6, 8, -4, 5, 9}; 
    KML_INT indx[9] = {1, 2, 4, 2, 4, 1, 3, 1, 4}; 
    KML_INT pntrb[4] = {1, 4, 6, 8}; 
    KML_INT pntre[4] = {4, 6, 8, 10}; 
    float x[4] = {1, 3, -2, 5}; 
    float y[4] = {0, 0, 0, 0}; 
    kml_sparse_status_t status = kml_sparse_scsrsv(opt, m, alpha, matdescra, val, indx, pntrb, pntre, x, y); 
    /* 
     *  Output Y: 
     *     0.500000   3.000000   1.500000   0.277778 
     * 
     */

Fortran interface:

    INTEGER(C_INT) :: OPT = KML_SPARSE_OPERATION_NON_TRANSPOSE 
    INTEGER(C_INT) :: M = 4 
    REAL(C_FLOAT) :: ALPHA = 1.0 
    CHARACTER(KIND=C_CHAR, LEN=4) :: MATDESCRA = "TLNF" ! General matrix with one-based indexing
    REAL(C_FLOAT) :: VAL(9), X(4), Y(4) 
    INTEGER(C_INT) :: INDX(9), PNTRB(4),PNTRE(4) 
    INTEGER(C_INT) :: STATUS  
    DATA VAL /2, -3, 7, 1, -6, 8, -4, 5, 9/ 
    DATA INDX /1, 2, 4, 2, 4, 1, 3, 1, 4/ 
    DATA PNTRB /1, 4, 6, 8/ 
    DATA PNTRE/4, 6, 8, 10/ 
    DATA X/1, 3, -2, 5/ 
    DATA Y/0, 0, 0, 0/ 
    STATUS = KML_SPARSE_SCSRSV(OPT, M, ALPHA, MATDESCRA, VAL, INDX, PNTRB, PNTRE, X, Y); 
    ! 
    !  OUTPUT Y: 
    !     0.500000   3.000000   1.500000   0.277778 
    !

Parent topic: Sparse BLAS Level 2 and Level 3 Functions