Fortran+ openmp实现实例

转载于：http://download.csdn.net/download/bingdaozaixian/4810039

PROGRAM parallel_01

USE omp_lib
IMPLICIT NONE

INTEGER :: i,j
INTEGER(4) :: time_begin, time_end, time_rate
REAL, DIMENSION(1:50,1:50) :: f, g
REAL :: k

WRITE(*,*) '开始进行串行计算'
!>@ 1、通过串行计算获得两个矩阵的初始化计算
CALL system_clock(time_begin,time_rate)
DO i = 1, 50
DO j = 1, 50
f(i,j) = i*j
k = k + 1
END DO
END DO

DO i = 1, 50
DO j = 1, 50
g(i,j) = i*j + 1
k = k + 1
END DO
END DO

CALL system_clock(time_end,time_rate)
WRITE(*,*) 'The value of k after serial computing is: ', k
WRITE(*,*) 'The time wasted on serial computing is: ',(time_end - time_begin)/time_rate

WRITE(*,*)
WRITE(*,*)
WRITE(*,*) '开始进行第一类串行计算—SECTIONS'

!>@ 2、通过块并行计算获得两个矩阵的初始化计算
k = 0 ! 重新初始化k的值
CALL system_clock(time_begin,time_rate)
CALL omp_set_num_threads(2)
!$omp parallel
!$omp sections private(i,j,k)
!$omp section
DO i = 1, 50
DO j = 1, 50
f(i,j) = i*j
k = k + 1
END DO
END DO
WRITE(*,*) 'The value of k after parallel computing is: ', k,', and it comes from the thread of ',omp_get_thread_num()

!$omp section
DO i = 1, 50
DO j = 1, 50
g(i,j) = i*j + 1
k = k + 1
END DO
END DO
WRITE(*,*) 'The value of k after parallel computing is: ', k,', and it comes from the thread of ',omp_get_thread_num()
!$omp end sections
!$omp end parallel

CALL system_clock(time_end,time_rate)
WRITE(*,*) 'The time wasted on the first class parallel computing is: ',(time_end - time_begin)/time_rate
WRITE(*,*)
WRITE(*,*)
WRITE(*,*) '开始进行第二类并行计算—DO'

!>@ 3、通过DO循环实现两个矩阵的初始化计算
k = 0 ! 重新初始化k的值
CALL system_clock(time_begin,time_rate)
!$omp parallel private(k,j,i)
!$omp do
DO i = 1, 50
DO j = 1, 50
f(i,j) = i*j
k = k + 1
! 去掉注释后，可现实每一次循环所在的线程ID
!               WRITE(*,*) 'The value of k after parallel computing is: ', k,', and it comes from the thread of ',omp_get_thread_num()
END DO
END DO
!$omp end do
!$omp end parallel

!$omp parallel private(k,j,i)
!$omp do
DO i = 1, 50
DO j = 1, 50
g(i,j) = i*j
k = k + 1
!                WRITE(*,*) 'The value of k after parallel computing is: ', k,', and it comes from the thread of ',omp_get_thread_num()
END DO
END DO
!$omp end do
!$omp end parallel
CALL system_clock(time_end,time_rate)
WRITE(*,*) 'The time wasted on the first class parallel computing is: ',(time_end - time_begin)/time_rate
END PROGRAM