Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 6/24/2024
Public

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?axpyi

Adds a scalar multiple of compressed sparse vector to a full-storage vector.

Syntax

call saxpyi(nz, a, x, indx, y)

call daxpyi(nz, a, x, indx, y)

call caxpyi(nz, a, x, indx, y)

call zaxpyi(nz, a, x, indx, y)

call axpyi(x, indx, y [, a])

Include Files

  • mkl.fi, blas.f90

Description

The ?axpyi routines perform a vector-vector operation defined as

y := a*x + y

where:

a is a scalar,

x is a sparse vector stored in compressed form,

y is a vector in full storage form.

The ?axpyi routines reference or modify only the elements of y whose indices are listed in the array indx.

The values in indx must be distinct.

Input Parameters

nz

INTEGER. The number of elements in x and indx.

a

REAL for saxpyi

DOUBLE PRECISION for daxpyi

COMPLEX for caxpyi

DOUBLE COMPLEX for zaxpyi

Specifies the scalar a.

x

REAL for saxpyi

DOUBLE PRECISION for daxpyi

COMPLEX for caxpyi

DOUBLE COMPLEX for zaxpyi

Array, size at least nz.

indx

INTEGER. Specifies the indices for the elements of x.

Array, size at least nz.

y

REAL for saxpyi

DOUBLE PRECISION for daxpyi

COMPLEX for caxpyi

DOUBLE COMPLEX for zaxpyi

Array, size at least max(indx(i)).

Output Parameters

y

Contains the updated vector y.

BLAS 95 Interface Notes

Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see BLAS 95 Interface Conventions.

Specific details for the routine axpyi interface are the following:

x

Holds the vector with the number of elements nz.

indx

Holds the vector with the number of elements nz.

y

Holds the vector with the number of elements nz.

a

The default value is 1.