mkl_?skymv

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 3/22/2024

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mkl_?skymv

Computes matrix - vector product for a sparse matrix in the skyline storage format with one-based indexing (deprecated).

Syntax

call mkl_sskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

call mkl_dskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

call mkl_cskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

call mkl_zskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

Include Files

mkl.fi

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_?skymv routine performs a matrix-vector operation defined as

y := alpha*A*x + beta*y

y := alpha*A^T*x + beta*y,

where:

alpha and beta are scalars,

x and y are vectors,

A is an m-by-k sparse matrix stored using the skyline storage scheme, A^T is the transpose of A.

NOTE:

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

Input Parameters

Parameter descriptions are common for all implemented interfaces with the exception of data types that refer here to the FORTRAN 77 standard types. Data types specific to the different interfaces are described in the section "Interfaces" below.

transa

CHARACTER*1. Specifies the operation.

If transa = 'N' or 'n', then y := alpha*A*x + beta*y

If transa = 'T' or 't' or 'C' or 'c', then y := alpha*A^T*x + beta*y,

m

INTEGER. Number of rows of the matrix A.

k

INTEGER. Number of columns of the matrix A.

alpha

REAL for mkl_sskymv.

DOUBLE PRECISION for mkl_dskymv.

COMPLEX for mkl_cskymv.

DOUBLE COMPLEX for mkl_zskymv.

Specifies the scalar alpha.

matdescra

CHARACTER. 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(1)='G') is not supported.

val

REAL for mkl_sskymv.

DOUBLE PRECISION for mkl_dskymv.

COMPLEX for mkl_cskymv.

DOUBLE COMPLEX for mkl_zskymv.

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

If matdescrsa(2)= 'L', then val contains elements from the low triangle of the matrix A.

If matdescrsa(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

INTEGER. 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

REAL for mkl_sskymv.

DOUBLE PRECISION for mkl_dskymv.

COMPLEX for mkl_cskymv.

DOUBLE COMPLEX for mkl_zskymv.

Array, size at least k if transa = 'N' or 'n' and at least m otherwise. On entry, the array x must contain the vector x.

beta

REAL for mkl_sskymv.

DOUBLE PRECISION for mkl_dskymv.

COMPLEX for mkl_cskymv.

DOUBLE COMPLEX for mkl_zskymv.

Specifies the scalar beta.

y

REAL for mkl_sskymv.

DOUBLE PRECISION for mkl_dskymv.

COMPLEX for mkl_cskymv.

DOUBLE COMPLEX for mkl_zskymv.

Array, size at least m if transa = 'N' or 'n' and at least k otherwise. On entry, the array y must contain the vector y.

Output Parameters

y: Overwritten by the updated vector y.

Interfaces

FORTRAN 77:

SUBROUTINE mkl_sskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

  CHARACTER*1   transa

  CHARACTER     matdescra(*)

  INTEGER       m, k

  INTEGER       pntr(*)

  REAL          alpha, beta

  REAL          val(*), x(*), y(*)

SUBROUTINE mkl_dskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

  CHARACTER*1   transa

  CHARACTER     matdescra(*)

  INTEGER       m, k

  INTEGER       pntr(*)

  DOUBLE PRECISION        alpha, beta

  DOUBLE PRECISION        val(*), x(*), y(*)

SUBROUTINE mkl_cdskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

  CHARACTER*1   transa

  CHARACTER     matdescra(*)

  INTEGER       m, k

  INTEGER       pntr(*)

  COMPLEX        alpha, beta

  COMPLEX        val(*), x(*), y(*)

SUBROUTINE mkl_zskymv(transa, m, k, alpha, matdescra, val, pntr, x, beta, y)

  CHARACTER*1   transa

  CHARACTER     matdescra(*)

  INTEGER       m, k

  INTEGER       pntr(*)

  DOUBLE COMPLEX        alpha, beta

  DOUBLE COMPLEX        val(*), x(*), y(*)

Parent topic: Sparse BLAS Level 2 and Level 3 Routines.

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

mkl_?skymv

Syntax

Include Files

Description

Input Parameters

Output Parameters

Interfaces

FORTRAN 77: