anchor.diff:  c
   c...  subroutine arguments
   c
  -      integer nextflag,ntractflag,ngravflag,nconcflag,nprestrflag,neq
  +      integer nextflag,ntractflag,ngravflag,nconcflag,neq
         double precision bextern(nextflag*neq),btraction(ntractflag*neq)
         double precision bgravity(ngravflag*neq),bconcforce(nconcflag*neq)
  -      double precision bprestress(nprestrflag*neq),bintern(neq)
  -      double precision bresid(neq)
  +      double precision bintern(neq),bresid(neq)
   c
   cdebug      integer idb
   c
  
positive.code: c~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  c
  c
        subroutine bsum(bextern,btraction,bgravity,bconcforce,bprestress,
       & bintern,bresid,nextflag,ntractflag,ngravflag,nconcflag,
       & nprestrflag,neq)
  c
  c...subroutine to sum all contributions to the external force vector,
  c   then subtract the internal force vector from the external vector
  
negative.code:         if(ngravflag.ne.izero) call daxpy(neq,one,bgravity,ione,
       &   bextern,ione)
          if(nconcflag.ne.izero) call daxpy(neq,one,bconcforce,ione,
       &   bextern,ione)
          call dcopy(neq,bextern,ione,bresid,ione)
  cdebug        write(6,*) "bextern:"
  