?axpyi

Syntax

FORTRAN 77:

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)

Fortran 95:

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

Include Files

The FORTRAN 77 interfaces are specified in the mkl_blas.fi include file, the Fortran 95 interfaces are specified in the blas.f90 include file, and the C interfaces are specified in the mkl_blas.h include file.

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, DIMENSION at least nz.

indx

INTEGER. Specifies the indices for the elements of x.

Array, DIMENSION at least nz.

y

REAL for saxpyi

DOUBLE PRECISION for daxpyi

COMPLEX for caxpyi

DOUBLE COMPLEX for zaxpyi

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

Output Parameters

y

Contains the updated vector y.

Fortran 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 Fortran 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.