kml_sparse_?doti

Compute the dot product of real vectors (Euclidean space).

res = x[0] * y[indx[0]] + x[1] * y[indx[1]] + ... + x[nz-1] * y[indx[nz-1]]

Interface Definition

C interface:

kml_sparse_status_t kml_sparse_sdoti(const KML_INT nz, const float *x,const KML_INT *indx, const float *y, float *doti);

kml_sparse_status_t kml_sparse_ddoti(const KML_INT nz, const double *x,const KML_INT *indx, const double *y, double *doti);

Fortran interface:

RES = KML_SPARSE_SDOTI(NZ, X, INDX, Y, DOTI);

RES = KML_SPARSE_DDOTI(NZ, X, INDX, Y, DOTI);

Parameters

Parameter	Type	Description	Input/Output
nz	Integer	Number of elements in the x and indx arrays.	Input
x	For sdoti, x is a single-precision floating-point array. For ddoti, x is a double-precision floating-point array.	Array x for storing non-zero elements. The size is at least nz.	Input
indx	Integer array	indx[i] indicates the serial number of the i-th element in the x array in the dense vector. The array size is at least nz.	Input
y	For sdoti, y is a single-precision floating-point array. For ddoti, y is a double-precision floating-point array.	Array y. The size is at least max(indx[i]).	Input
doti	For sdoti, doti is of the single-precision floating-point type. For ddoti, doti is of the double-precision floating-point type.	Dot product of x and y.	Input/Output

Return Value

Function execution status. The enumeration type is kml_sparse_status_t.

Dependencies

C: "kspblas.h"

Fortran: "kspblas.f03"

Examples

C interface:

    KML_INT nz = 2; 
    float doti = 0; 
    KML_INT indx[2] = {1, 2}; 
    float x[2] = {1, 3}; 
    float y[4] = {-1, 1, 5, 3}; 
    kml_sparse_status_t status = kml_sparse_sdoti(nz, x, indx, y, &doti); 
 
    /* 
     *  Output doti: 
     *    16.000000 
     */

Fortran interface:

    INTEGER(C_INT) :: NZ = 2 
    REAL(C_FLOAT), TARGET :: DOTI 
    TYPE(C_PTR) :: PDOTI 
    INTEGER(C_INT) :: STATUS 
    INTEGER(C_INT) INDX(2) 
    REAL(C_FLOAT) X(2) 
    REAL(C_FLOAT) Y(2) 
    DATA INDX/1, 2/ 
    DATA X/1, 3/ 
    DATA Y/-1, 1, 5, 3/ 
    PDOTI = C_LOC(DOTI) 
    STATUS = KML_SPARSE_SDOTI(NZ, X, INDX, Y, PDOTI) 
    /* 
     *  OUTPUT DOTI: 
     *    16.000000 
     */

Parent topic: Sparse BLAS Level 1 Functions