libgomp/testsuite/libgomp.fortran/omp_reduction.f

   1 C******************************************************************************
   2 C FILE: omp_reduction.f
   3 C DESCRIPTION:
   4 C   OpenMP Example - Combined Parallel Loop Reduction - Fortran Version
   5 C   This example demonstrates a sum reduction within a combined parallel loop
   6 C   construct.  Notice that default data element scoping is assumed - there
   7 C   are no clauses specifying shared or private variables.  OpenMP will
   8 C   automatically make loop index variables private within team threads, and
   9 C   global variables shared.
  10 C AUTHOR: Blaise Barney  5/99
  11 C LAST REVISED:
  12 C******************************************************************************
  13
  14       PROGRAM REDUCTION
  15
  16       INTEGER I, N
  17       REAL A(100), B(100), SUM
  18
  19 !     Some initializations
  20       N = 100
  21       DO I = 1, N
  22         A(I) = I *1.0
  23         B(I) = A(I)
  24       ENDDO
  25       SUM = 0.0
  26
  27 !$OMP PARALLEL DO REDUCTION(+:SUM)
  28       DO I = 1, N
  29         SUM = SUM + (A(I) * B(I))
  30       ENDDO
  31
  32       PRINT *, '   Sum = ', SUM
  33       END