Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 3/22/2024
Public

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Document Table of Contents

mkl_?skysv

Solves a system of linear equations for a sparse matrix in the skyline format with one-based indexing (deprecated).

Syntax

void mkl_sskysv (const char *transa , const MKL_INT *m , const float *alpha , const char *matdescra , const float *val , const MKL_INT *pntr , const float *x , float *y );

void mkl_dskysv (const char *transa , const MKL_INT *m , const double *alpha , const char *matdescra , const double *val , const MKL_INT *pntr , const double *x , double *y );

void mkl_cskysv (const char *transa , const MKL_INT *m , const MKL_Complex8 *alpha , const char *matdescra , const MKL_Complex8 *val , const MKL_INT *pntr , const MKL_Complex8 *x , MKL_Complex8 *y );

void mkl_zskysv (const char *transa , const MKL_INT *m , const MKL_Complex16 *alpha , const char *matdescra , const MKL_Complex16 *val , const MKL_INT *pntr , const MKL_Complex16 *x , MKL_Complex16 *y );

Include Files

  • mkl.h

Description

This routine is deprecated, but no replacement is available yet in the Inspector-Executor Sparse BLAS API interfaces. You can continue using this routine until a replacement is provided and this can be fully removed.

The mkl_?skysv routine solves a system of linear equations with matrix-vector operations for a sparse matrix in the skyline storage format:

y := alpha*inv(A)*x

or

y := alpha*inv(AT)*x,

where:

alpha is scalar, x and y are vectors, A is a sparse upper or lower triangular matrix with unit or non-unit main diagonal, AT is the transpose of A.

NOTE:

This routine supports only one-based indexing of the input arrays.

Input Parameters

transa

Specifies the system of linear equations.

If transa = 'N' or 'n', then y := alpha*inv(A)*x

If transa = 'T' or 't' or 'C' or 'c', then y := alpha*inv(AT)* x,

m

Number of rows of the matrix A.

alpha

Specifies the scalar alpha.

matdescra

Array of six elements, specifies properties of the matrix used for operation. Only first four array elements are used, their possible values are given in Table “Possible Values of the Parameter matdescra (descra)”. Possible combinations of element values of this parameter are given in Table “Possible Combinations of Element Values of the Parameter matdescra.

NOTE:

General matrices (matdescra[0]='G') is not supported.

val

Array containing the set of elements of the matrix A in the skyline profile form.

If matdescra[2]= 'L', then val contains elements from the low triangle of the matrix A.

If matdescsa[2]= 'U', then val contains elements from the upper triangle of the matrix A.

Refer to values array description in Skyline Storage Scheme for more details.

pntr

Array of length (m + 1) for lower triangle, and (k + 1) for upper triangle.

It contains the indices specifying in the val the positions of the first element in each row (column) of the matrix A. Refer to pointers array description in Skyline Storage Scheme for more details.

x

Array, size at least m.

On entry, the array x must contain the vector x. The elements are accessed with unit increment.

y

Array, size at least m.

On entry, the array y must contain the vector y. The elements are accessed with unit increment.

Output Parameters

y

Contains solution vector x.