caxpyi

NAME

caxpyi, daxpyi, saxpyi, zaxpyi - Compute y := alpha * x + y

SYNOPSIS

  SUBROUTINE CAXPYI( NZ, A, X, INDX, Y)
  COMPLEX A
  COMPLEX X(*), Y(*)
  INTEGER NZ
  INTEGER INDX(*)
 
  SUBROUTINE CAXPYI_64( NZ, A, X, INDX, Y)
  COMPLEX A
  COMPLEX X(*), Y(*)
  INTEGER*8 NZ
  INTEGER*8 INDX(*)

F95 INTERFACE

  SUBROUTINE AXPYI( [NZ], [A], X, INDX, Y)
  COMPLEX :: A
  COMPLEX, DIMENSION(:) :: X, Y
  INTEGER :: NZ
  INTEGER, DIMENSION(:) :: INDX
 
  SUBROUTINE AXPYI_64( [NZ], [A], X, INDX, Y)
  COMPLEX :: A
  COMPLEX, DIMENSION(:) :: X, Y
  INTEGER(8) :: NZ
  INTEGER(8), DIMENSION(:) :: INDX

PURPOSE

caxpyi 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 10, i = 1, n
               y(indx(i)) = alpha * x(i) + y(indx(i))
          10 continue

ARGUMENTS

* 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.