anchor.diff:  clater        if(ierr.ne.izero) return
   c
   clater        call formdf_ld(
  -clater     &   b,neq,                                                         ! force
  +clater     &   bintern,neq,                                                   ! force
   clater     &   x,d,dcur,numnp,                                                ! global
   clater     &   s,stemp,                                                       ! stiff
   clater     &   dmat,ien,lm,lmx,infiel,iddmat,ndmatsz,numelt,nconsz,           ! elemnt
  
positive.code: clater        if(ierr.ne.izero) return
  c
  clater        call iterate(
  clater     &   alnz,pcg,zcg,ja,                                               ! sparse
  clater     &   b,btot,bres,pvec,gvec1,gvec2,grav,                             ! force
  clater     &   x,d,deld,dprev,dcur,id,iwink,wink,nsysdat,                     ! global
  clater     &   dx,deldx,dxcur,idx,iwinkx,winkx,idslp,ipslp,                   ! slip
  clater     &   nfault,dfault,tfault,                                          ! fault
  clater     &   s,stemp,                                                       ! stiff
  
negative.code: clater        if(ierr.ne.izero) return
  c
  clater        if(numfn.ne.izero) call formf_ld(
  clater     &   bintern,neq,                                                   ! force
  clater     &   x,numnp,                                                       ! global
  clater     &   s,stemp,                                                       ! stiff
  clater     &   dmat,ien,lm,lmx,infiel,iddmat,ndmatsz,numelt,nconsz,           ! elemnt
  