! FTANGLE v1.61,
! created with UNIX on "Friday, September 25, 1998 at 8:02." 
!  COMMAND LINE: "ftangle gamma.web"
!  RUN TIME:     "Monday, October 5, 1998 at 20:05."
!  WEB FILE:     "gamma.web"
!  CHANGE FILE:  (none)
      !* 1: * 
!line 126 "gamma.web"
      
      
      real(kind=long)function big_gamma(a,x)
      real(kind=long),intent(in)::a,x
!* 2: * 
!line 193 "gamma.web"
      
      
      real(kind=long),parameter::epsilon=1.0E-9
      real(kind=long)::a0,b0,a1,b1,r_old,r_new,delta
      integer::n
      
      
!* :2 * 
!line 130 "gamma.web"
      
      
      if(x.LE.0.0_long)then
      if(x.LT.0.0_long)then
      stop 'error: big_gamma called with x < 0'
      
      
      else
      big_gamma=gamma(a)
      
      
      
      end if
      else
!* 3: * 
!line 236 "gamma.web"
      
      
      a0=0.0_long
      b0=1.0_long
      a1=1.0_long
      b1=x
      r_old=a1/b1
      delta=r_old
      n=1
      
!* :3 * 
!line 144 "gamma.web"
      
!* 4: * 
!line 282 "gamma.web"
      
      
      do while(abs(delta).GT.abs(epsilon*r_old))
      a0=a1+(n-a)*a0
      
      b0=b1+(n-a)*b0
      
      a1=x*a0+n*a1
      
      b1=x*b0+n*b1
      
      r_new=a1/b1
      
      delta=r_new-r_old
      
      r_old=r_new
      n=n+1
      end do
      
!* :4 * 
!line 145 "gamma.web"
      
      big_gamma=r_new*exp(-x+a log(x))
      
      
      end if
      
      end function big_gamma
      
!* :1 *