anchor.diff:  c******  Another thing to consider is that I will need to pass in some extra
   c******  info that isn't currently needed for the small strain case.
   c
  -      if(lgdefp.eq.0.and.ibbarp.eq.0) then
  +      if(lgdefp.eq.izero.and.ibbarp.eq.izero) then
           call matinit_drv(
        &   alnz,ja,nnz,neq,                                               ! sparse
        &   x,d,iwink,wink,numnp,nwink,                                    ! global
  
positive.code: c
  cdebug      write(6,*) "Hello from elastc_f!"
  c
        if(idout.ne.0) open(kw,file=ofile,status="old",access="append")
        if(idsk.eq.0) open(kp,file=pfile,status="old",access="append")
        if(idsk.eq.1) open(kp,file=pfile,status="old",form="unformatted",
       & access="append")
        skc=iskopt.ge.0.and.iskopt.ne.1.and.numslp.ne.0
        call fill(bres,zero,neq)
        call fill(btot,zero,neq)
        call fill(gvec1,zero,neq)
  
negative.code: c
  c...add differential forces across internal free interfaces
  c
        if(numdif.ne.izero) then
          call loadx(btot,diforc,histry,idx,idhist,neq,numnp,nhist,nstep,
       &   lastep,ierr,errstrng)
          if(ierr.ne.izero) return
        end if
  c
  c...  initialize elastic material matrices and stiffness matrix, 
  c     compute forces due to applied displacements and split nodes,
  