anchor.diff:  double precision g,dble_fact,expo
   double precision, parameter :: sq_pi_ov_2=dsqrt(dacos(-1.d0)*0.5d0)
   expo=0.5d0*dfloat(n+1)
  -crochet=dble_fact(n-1)/(2.d0*g)**expo
  +crochet=dble_fact(n-1)/(g+g)**expo
   if(mod(n,2).eq.0)crochet=crochet*sq_pi_ov_2
   end
   
  
positive.code:       double precision xq(100),wq(100)
  
        u=(a+b)/(2.d0*dsqrt(gam))
        factor=dexp(u**2-arg)/dsqrt(gam)
  
  xq(1)= 5.38748089001123    
  xq(2)= 4.60368244955074   
  
negative.code:     int=0.d0
      done=.false.
  
      n_1 = n+n+1
      m_1 = m+m+1
      nlm = n+m+l
      pi=dacos(-1.d0)
      a_over_b_square = (a/b)**2
  