!----------------------!
 real(8) function ran()
!----------------------------------------------!
! 64-bit congruental generator                 !
! iran64=oran64*2862933555777941757+1013904243 !
!----------------------------------------------!
 implicit none

 real(8)    :: dmu64
 integer(8) :: ran64,mul64,add64
 common/bran64/dmu64,ran64,mul64,add64

 ran64=ran64*mul64+add64
 ran=0.5d0+dmu64*dble(ran64)

 end function ran
!----------------!

!---------------------!
 subroutine initran(w)
!---------------------!
 implicit none

 integer(8) :: irmax
 integer(4) :: w,nb,b

 real(8)    :: dmu64
 integer(8) :: ran64,mul64,add64
 common/bran64/dmu64,ran64,mul64,add64
      
 irmax=2_8**31
 irmax=2*(irmax**2-1)+1
 mul64=2862933555777941757_8
 add64=1013904243
 dmu64=0.5d0/dble(irmax)

 open(10,file='seed.in',status='old')
 read(10,*)ran64
 close(10)
 if (w.ne.0) then
    open(10,file='seed.in',status='unknown')
    write(10,*)abs((ran64*mul64)/5+5265361)
    close(10)
 endif

 end subroutine initran
!----------------------!