anchor.diff:  c
   c...add pressure forces,if present, to global load vector
   c
  -clater        if(numpr.ne.0.and.(iter.eq.1.or.updats)) call addpr(
  +clater        if(numpr.ne.0.and.updats.and.iprestress.eq.0) call addpr(
   clater     &   btot,bres,x,d,dx,tfault,histry,skew,
   clater     &   ien,infin,lm,lmx,lmf,
   clater     &   ielno,iside,ihistry,pres,pdir,pvec,gvec2,fulout,
  
positive.code: c
  c...compute the global displacement increment vector using a
  c   preconditioned conjugate gradients iterative solver.  Upon
  c   return the vector gvec2 contains the displacements.
  c
          call pcginv(alnz,bresid,dispvec,bwork,pcg,zcg,dprev,rmin,rmult,
       &   gcurr,gprev,ja,nsiter,neq,nprevdflag,nnz,ndtot,idout,kto,kw,
  
negative.code: c
  c...add gravity body forces to global load vector
  c
          if(updats) then
            call gload_drv(
       &     bgravity,ngravflag,grav,neq,                                 ! force
       &     x,d,numnp,                                                   ! global
  