XL Fortran Enterprise Edition for AIX : User's Guide - IBM

close(10)
open(10, file="fun10.out", form="formatted")
do j = 1, number_of_threads
read(10, *) array1
do i = 1, 1000
if (array1(i) /= array(i)) then
print *, "Result is wrong."
stop
endif
end do
end do
close(10, status="delete")
print *, "Normal ending."
end
subroutine f_mt_exec(thread_number)
integer thread_number
integer array(1000)
common /x/ array
write(10, *) array
end
Example 3 - Valid Fortran SMP Source File
!*****************************************************************
!* This example uses a PARALLEL construct and a DO construct *
!* to calculate the value of pi. *
!*****************************************************************
program compute_pi
integer n, i
real*8 w, x, pi, f, a
f(a) = 4.d0 /(1.d0 + a*a) !! function to integrate
pi = 0.0d0
!$OMP PARALLEL private(x, w, n), shared(pi)
n = 10000
!! number of intervals
w = 1.0d0/n
!! calculate the interval size
!$OMP DO reduction(+: pi)
do i = 1, n
x = w * (i - 0.5d0)
pi = pi + f(x)
enddo
!$OMP END DO
!$OMP END PARALLEL
print *, "Computed pi = ", pi
end
Example 4 - Invalid Fortran SMP Source File
!*****************************************************************
!* In this example, fort_sub is invoked by multiple threads. *
!* *
!* This example is not valid because *
!* fort_sub and another_sub both declare /block/ to be *
!* THREADLOCAL. They intend to share the common block, but *
!* they are executed via different threads. *
!* *
!* To "fix" this problem, one of the following approaches can *
!* be taken: *
!* (1) The code for another_sub should be brought into the loop.*
!* (2) "j" should be passed as an argument to another_sub, and *
!* the declaration for /block/ should be removed from *
!* another_sub. *
408 XL Fortran Enterprise Edition for AIX : User’s Guide