anchor.diff:  c...  loop over elements in group if there is material property
   c     variation for the material type.
   c
  -        nstateinc=nstr*nstate
           do ind=matgpt,matgpt+nmatel-1
             iel=infiel(4,ind)
             ietype=infiel(3,iel)
  
positive.code: c...  local variables
  c
        integer iel,indstate0,inddmat0,ietype,nstate,ng
        integer inddmatg,l,nstateinc,ind,indstate,inddmat,ngauss,indstateg
        integer indien,nen,nee,ngtest,ngaussdim
        double precision tmax
  c
  
negative.code:      &       ierr,errstrng)
              if(ierr.ne.izero) return
              tminmax=min(tminmax,tmax)
              inddmatg=inddmatg+ione
              indstateg=indstateg+nstate
            end do
          end do
        end if
  