nf.f90

产生服从N(0,1)分布的子程序（fortran）

!     ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
!                          产 生 N(0,1) 分布随机数子程序
!     ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	  function NF(idum)
	  implicit real(i-n)
	  integer idum
	  real ran1,nf,v1,v2,w,fac	
	
100	  v1=ran1(idum)
	  v2=ran1(idum)
	  w=(2*v1-1)**2+(2*v2-1)**2
	  if (w.gt.1.0) goto 100
	  if (w.eq.0.0) goto 100
	  fac=sqrt(-2*log(w)/w)
	  NF=v1*fac
   	  end
!  	  ------------------------------------------------------------------