anchor.diff:  
   C Initialize random number generator
         call raninit(idum)
  +      if (seed.gt.0) idum = -seed
   
   C Perturb input data
     101 read(input,*,end=102) (val(i),i=1,nvar),(dval(i),i=1,nvar)
  
positive.code:       write(*,*)
       1 '-n NVAR     Number of data variables'
        write(*,*)
       1 '-h          Online help'
        write(*,*)
        STOP
  
negative.code: C----
        IMPLICIT none
        CHARACTER*80 ifile,ofile
        INTEGER i,nvar,input,output,idum,seed
        REAL*8 val(10),dval(10)
        EXTERNAL ran2
        REAL ran2,random
  
  C Parse command line
        call gcmdln(ifile,ofile,nvar,seed)
        if (ifile.eq.'stdin') then
            input = 5
        else
  