anchor.diff:  c
   c
         subroutine skcomp(x,d,skew,idslp,ipslp,ipstrs,numsn,numnp,nstep,
  -     & lgdefp,kto)
  +     & lgdefp,ierr,errstrng)
   c
   c...  subroutine to compute skew angles for a given load vector and
   c     fault orientation
  
positive.code: c
  c...  subroutine arguments
  c
        integer ipstrs,numsn,numnp,nstep,lgdefp,kto
        integer idslp(numsn),ipslp(npdim,numsn)
        double precision x(nsd,numnp),d(ndof,numnp),skew(nskdim,numnp)
  c
  c...  intrinsic functions
  c
  
negative.code:       if(numsn.eq.ifour) nd=ifour
        if(numsn.eq.ithree) nd=ithree
        if(numsn.lt.ithree) then
          ierr=112
          errstrng="skcomp"
          return
        end if
        ncvm=ithree
        ldtmp=lgdefp
  