一个有关提高运算速度的问题

li913

[Fortran] 纯文本查看 复制代码

  PROGRAM test
      IMPLICIT NONE
      REAL, ALLOCATABLE :: a(:),b(:),hhs(:)
      INTEGER :: i, z, j, k, tn, num, numm
      REAL    :: summ, cos2, r1, q1, w1
      character(160):: filename
      Real(8) time
      Integer(4) time0, time1, dtime
      
       num=100
       numm=num*num
       tn=1000
       ALLOCATE(a(num),b(num),hhs(numm))
      Print*, 'Running...'
      Call system_clock(time0)
      OPEN(10, FILE='output.dat',status='unknown' )

      Do i=1,tn       
      write(filename,'(i6)') i
      Open(200,File="D:\x\"//trim(adjustl(filename))//'.dat',status='old')  
      READ(200,*) a
      close(200)
      Open(300,File="D:\y\"//trim(adjustl(filename))//'.dat',status='old')  
      READ(300,*) b
      close(300)
      z=0
      summ=0.0
      r1 = 20
      do  j = 1, num 
      do k = 1, num
      z=z+1
      q1 = b(j)-a(k)
      cos2 = (r1*q1+r1*r1+q1*q1)**2/3
      w1=sqrt(q1*q1+r1*r1)
      if (w1.GT.0.and.w1.LE.20) then
      hhs(z)=cos2/(w1*w1*w1)
      endif
      enddo
      enddo
      summ=sum(hhs)
      WRITE(10,'(1X,F12.6)') summ
      enddo
      DEALLOCATE(a,b)
      close(10)
      Call system_clock(time1, dtime)
      time = 1D0*(time1-time0)/dtime
      Write (*, '(a7,f16.7)') 'Time = ', time
      END PROGRAM