anchor.diff:  
   
   * function to generate gauss distribution
  -      double precision function gaus(x0,sig)
  +      double precision function qpgaus(x0,sig)
         IMPLICIT DOUBLE PRECISION(A-H, O-Z)
    41   u1=pyr(0) 
         u2=pyr(0)  
  
positive.code:       v2=2.d0*u2-1.d0 
        s=v1**2+v2**2
        if(s.gt.1) go to 41
        gaus=v1*dsqrt(-2.d0*dlog(s)/s)*sig+x0
        return
        end    
  
negative.code: *     generate 'njet' number of hard parton-parton scatterings with PYTHIA 
        IMPLICIT DOUBLE PRECISION(A-H, O-Z)
        double precision npar0,nbco0,npart,nbcol,npart0
        double precision qpgaus
        
        INTEGER PYK,PYCHGE,PYCOMP
        CHARACTER beam*2,targ*2
        external pydata 
        external pyp,pyr,pyk,pyquen,shad1,qpgaus
        
        common /pyjets/ n,npad,k(4000,5),p(4000,5),v(4000,5)
        common /hyjets/ nhj,nhp,khj(150000,5),phj(150000,5),vhj(150000,5)
  