subroutine tlocal(id,tauf,t)
c     ============================
c
c     local temperature as a a function of optical depth
c     for a grey model
c
c     input;   ID   - depth index
c              TAUF - current estimate of the flux-mean opacity
c     output:  T    - local temperature
c
      INCLUDE 'IMPLIC.FOR'
      INCLUDE 'BASICS.FOR'
      INCLUDE 'MODELQ.FOR'
      parameter (c1=0.8112,c2=3.966e14,c3=6.745e-10,c4=0.96,
     *           c23=c2*c3,c34=c3*c4)
c
      COMMON/FLXAUX/T4,PGAS,PRAD,PGM,PRADM,ITGMAX,ITGMX0
      COMMON/FACTRS/GAMJ(MDEPTH),GAMH,FAK0
C
      if(tdisk.gt.0.) then
         t=tdisk
         return
      end if
c
      vis=viscd(id)/(3.*dm(nd))
      extra=4.*fak0*wdil*(tstar/teff)**4
      gj=gamj(id)
      gh=gamh*5.7735e-1
      gg=(tauf-tauthe(id))*fractv+gh+extra
c
      if(icompt.eq.0.or.icomgr.eq.0) then
         t=(0.75*t4*(gj*gg+vis/abplad(id)))**0.25
         return
      end if
c
      epsbar=abplad(id)/abrosd(id)
      tfor=c1*teff*epsbar**(-0.125)
      tf0=tfor
      if(tauf.gt.un.and.tfor.lt.temp(id).or.tauf.ge.100.) then
         tfor=0.
         b=gg*(c3-c34) 
         b=0.
       else
         b=gg*c3
      end if
      a=epsbar/(0.75*t4)
      c=gg*(epsbar*gj+c34*tfor)+vis/abrosd(id)
      call quartc(a,b,c,t1)
      t=t1
c
      return
      end