OpenMPI для Windows

program ompPrime

#ifdef _OPENMP
   include 'omp_lib.h'  !needed for OMP_GET_NUM_THREADS()
#endif

integer :: start = 1
integer :: end = 100000000
integer :: number_of_primes = 0
integer :: number_of_41primes = 0
integer :: number_of_43primes = 0
integer index, factor, limit, nthr
double precision st, fin
real rindex, rlimit
logical prime, print_primes

CALL CPU_TIME(st)

print_primes = .false.
nthr = 1 ! assume just one thread
print *, ' Range to check for Primes:',start,end

#ifdef _OPENMP
!$omp parallel
!$omp single
   nthr = OMP_GET_NUM_THREADS()
   print *, ' We are using',nthr,' thread(s)'
!$omp end single!
!$omp do private(factor, limit, prime) &
   SCHEDULE(dynamic,10) &
   reduction(+:number_of_primes,number_of_41primes,number_of_43primes)
#else
   print *, ' We are using',nthr,' thread(s)'
#endif

do index = start, end, 2   !workshared loop

   limit = int(sqrt(real(index)))
   prime = .true.  ! assume number is prime
   factor = 3

   do
      if(prime .and. factor .le. limit) then
         if(mod(index,factor) .eq. 0) then
            prime = .false.
         endif
         factor = factor + 2
      else
         exit  ! we can jump out of non-workshared loop
      endif
   enddo

   if(prime) then
      if(print_primes) then
         print *, index, ' is prime'
      endif

      number_of_primes = number_of_primes + 1

      if(mod(index,4) .eq. 1) then
         number_of_41primes = number_of_41primes + 1
      endif

      if(mod(index,4) .eq. 3) then
         number_of_43primes = number_of_43primes + 1
      endif

   endif   ! if(prime)
enddo
!$omp end do
!$omp end parallel

CALL CPU_TIME(fin)
print '("Time = ",1P6E12.4," seconds.")',fin-st

print *,number_of_primes
read *,number_of_primes

end program ompPrime

gfortran -cpp -fopenmp -o ompPrime ompPrime.f90

./ompPrime
  Range to check for Primes:           1   100000000
  We are using           4  thread(s)
Time =   1.4891E+02
     5761455
 
OMP_NUM_THREADS=2 ./ompPrime
  Range to check for Primes:           1   100000000
  We are using           2  thread(s)
Time =   9.4435E+01
     5761455

OMP_NUM_THREADS=1 ./ompPrime
  Range to check for Primes:           1   100000000
  We are using           1  thread(s)
Time =   8.8408E+01
     5761455