anchor.diff:       1 '-seed SEED  Start random numbers with integer SEED ',
        2                  '(useful for continuing chain of rands)'
         write(*,*)
  -     1 '-normal     Use normal distribution with 95% confidence at',
  -     2              'd values (default: uniform distribution)'
  +     1 '-normal VAR Use normal distribution with 95% confidence at',
  +     2              'd for VAR (default: uniform distribution)'
         write(*,*)
        1 '-p          Print results to standard output'
         write(*,*)
  
positive.code:               call getarg(i,tag)
                read(tag,*) seed
            elseif (tag(1:7).eq.'-normal') then
                distro = 2
            elseif (tag(1:2).eq.'-n') then
                i = i + 1
                call getarg(i,tag)
  
negative.code:       endif
  
  C Initialize random number generator
        irand = 0
        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)
            do 104 i = 1,nvar
                if (distro(i).eq.1) then
                    val(i) = val(i) + dval(i)*(2.0d0*ran2(idum)-1.0d0)
                elseif (distro(i).eq.2) then
                    if (irand.eq.0) then
                        call nrand(r1,r2,idum)
                        irand = 1
  