NAME

daxpyi - Compute y := alpha * x + y

SYNOPSIS

 SUBROUTINE DAXPYI(NZ, A, X, INDX, Y)

 DOUBLE PRECISION A
 DOUBLE PRECISION X(*), Y(*)
 INTEGER NZ
 INTEGER INDX(*)

 SUBROUTINE DAXPYI_64(NZ, A, X, INDX, Y)

 DOUBLE PRECISION A
 DOUBLE PRECISION X(*), Y(*)
 INTEGER*8 NZ
 INTEGER*8 INDX(*)

F95 INTERFACE SUBROUTINE AXPYI([NZ], [A], X, INDX, Y)

 REAL(8) :: A
 REAL(8), DIMENSION(:) :: X, Y
 INTEGER :: NZ
 INTEGER, DIMENSION(:) :: INDX

 SUBROUTINE AXPYI_64([NZ], [A], X, INDX, Y)

 REAL(8) :: A
 REAL(8), DIMENSION(:) :: X, Y
 INTEGER(8) :: NZ
 INTEGER(8), DIMENSION(:) :: INDX

DAXPYI Compute y := alpha * x + y where alpha is a scalar, x is a sparse vector, and y is a vector in full storage form

 do i = 1, n
   y(indx(i)) = alpha * x(i) + y(indx(i))
 enddo

NZ (input) - INTEGER: Number of elements in the compressed form. Unchanged on exit.
A (input): On entry, ALPHA specifies the scaling value. Unchanged on exit.
X (input): Vector containing the values of the compressed form. Unchanged on exit.
INDX (input) - INTEGER: Vector containing the indices of the compressed form. It is assumed that the elements in INDX are distinct and greater than zero. Unchanged on exit.
Y (output): Vector on input which contains the vector Y in full storage form. On exit, only the elements corresponding to the indices in INDX have been modified.