Listing 1. Example HPF Subroutine
SUBROUTINE GAUSS_ELIM_90 ( A, X, Y )
REAL, DIMENSION(:,:), INTENT(INOUT) :: A
REAL, DIMENSION(:), INTENT(INOUT) :: X, Y
REAL TEMP
REAL SWAP(SIZE(X))
!HPF$ ALIGN SWAP(:) WITH A(*,:)
!HPF$ ALIGN Y(:) WITH *A(:,*)
!HPF$ ALIGN X(:) WITH *A(:,*)
!HPF$ DISTRIBUTE A *(CYCLIC,*)
INTEGER i,j, n, location, location_array(1)
character*10 time
n = SIZE( X )
DO i = 1, n-1
location_array = MAXLOC( ABS(A(i:n,i)) )
location = location_array(1)+i-1
SWAP(i:n) = A(location,i:n)
TEMP = Y(location)
IF (location /= i) THEN
A(location,i:n) = A(i,i:n)
A(i,i:n) = SWAP(i:n)
Y(location) = Y(i)
Y(i) = TEMP
ENDIF
DO j = i+1, n
A(j,i) = A(j, i) / swap(i)
A(j, i+1:n) = A(j, i+1:n ) - a(j, i) &
* SWAP(i+1:n)
Y(j) = Y(j) - a(j,i) * TEMP
ENDDO
ENDDO
X(n) = Y(n) / A(n,n)
DO i = n-1, 1, -1
Y(1:i) = Y(1:i) - X(i+1) * A(1:i, i+1)
X(i) = Y(i) / A(i,i)
ENDDO
END SUBROUTINE GAUSS_ELIM_90
Copyright © 1994 - 2019 Linux Journal. All rights reserved.