anchor.diff:        fac=e/(pr2*pr3)
         dd=pr1*fac
         od=pr*fac
  -      ss=pr3*fac
  +      ss=half*pr3*fac
         do i=1,3
           dmat(iddmat(i,i))=dd
           dmat(iddmat(i+3,i+3))=ss
  
positive.code:       dmat(iddmat(1,2))=f1-f2
        dmat(iddmat(1,3))=dmat(iddmat(1,2))
        dmat(iddmat(2,3))=dmat(iddmat(1,2))
        dmat(iddmat(4,4))=three*f2
        dmat(iddmat(5,5))=dmat(iddmat(4,4))
        dmat(iddmat(6,6))=dmat(iddmat(4,4))
  cdebug      write(6,*) "dmat:",(dmat(idb),idb=1,nddmat)
        return
        end
  c
  c
        subroutine td_strs_5(state,dstate,state0,ee,dmat,prop,rtimdat,
       & rgiter,ntimdat,iddmat,tmax,nstate,nstate0,nprop,matchg,ierr,
       & errstrng)
  c
  c...  subroutine to compute the current values for stress, total strain,
  c     and viscous strain increment.
  
negative.code:       integer nstate,nstate0,nprop,ierr
        integer iddmat(nstr,nstr)
        character errstrng*(*)
        double precision state(nstate),dstate(nstate)
        double precision state0(nstate0),dmat(nddmat),prop(nprop),tmax
        logical matchg
  c
  