请教，随机数的问题

楚香饭

我写了个版本，看是否是你需要的。

[Fortran] 纯文本查看 复制代码

Program www_fcode_cn
  Implicit None
  Integer , parameter :: DP = Kind(0.0D0)
  Integer :: s( 100 )
  integer :: i , k , l
  Real( Kind = DP ) :: m1 , x , y , z , m2
  open (365,file='data.dat')
  call random_seed()
  do i=1,size(s)
    call random_number(x)
    if (x.le.0.5) then
      s(i)=1
    else
      s(i)=-1
    end if
  end do
  m1 = CalcM( S )
  Do k = 1 , 10000
    call random_number(y)
    l=1+aint(100*y)
    s(l)=-s(l)
    m2 = CalcM( S )
    call random_number(z)
    i=1+aint(100*z)
    if (s(i) < exp(m2-m1)) s(l)=-s(l)
    m1=m2
    write(365,*) m1
  end do
  
contains

  Real( Kind = DP ) Function CalcM( s )
    Integer :: s(:)
    integer :: j , n
    n = size( s )
    CalcM = -1.0_DP * s(1) * s(n)
    Do j = 1 , n - 1
      CalcM = CalcM - s(j) * s(j+1)
    end do
  End Function CalcM

End Program www_fcode_cn