计算耗时每次相差0.5秒

shrine

[Fortran] 纯文本查看 复制代码

      program main
      Use DFPort
      Use Kernel32

      integer , parameter :: QP = Selected_real_kind( 18 )
      integer::a , b , f,iss
      real(kind=QP)::time_begin,time_end    

      CALL CPU_TIME ( time_begin )
      iss = QueryPerformanceFrequency( Loc(f) )
      iss = QueryPerformanceCounter( Loc(a) )

......
......!computing
.....

      iss = QueryPerformanceCounter( Loc(b) )
      CALL CPU_TIME ( time_end )
      write(*,*)'Time of operation was ',(b-a)*1.0e-8_QP/(f*1.0e-8_QP), ' seconds' ,time_end-time_begin       
      end 

这两种方法本身相差0.2秒
连续两次计算，相同的方法居然相差0.5秒，这也太多了吧