subroutine UnivPhotoFit()
      implicit none
      include '../testarea/LeafGasParams.h'
      include '../testarea/LeafGasHybridFit.h'
      integer i,j,k,Priornumrubis,Priornumrubp,Priornumtpu,
     &Currentnumrubis,Currentnumrubp,Currentnumtpu,Postnumrubis,
     &Postnumrubp,Postnumtpu,Postilimittype
      double precision term,term1,term2,term3,term4,term5,term6,
     &term7,term8,term9
!
      if(Prioriknowlimit.eq.1.or.Prioriknowlimit.eq.2)then
        ntotsamples=0
        do i=1,nFixedPoints
          ntotsamples=ntotsamples+1
          Prioriphotolimit(ntotsamples)=Fixediphotolimit(i)
        enddo
        do j=1,numACicurves
          do i=1,nACiPoints(j)
            ntotsamples=ntotsamples+1
            Prioriphotolimit(ntotsamples)=ACiiphotolimit(i,j)
          enddo
        enddo
        do j=1,numALightcurves
          do i=1,nALightPoints(j)
            ntotsamples=ntotsamples+1
            Prioriphotolimit(ntotsamples)=ALightiphotolimit(i,j)
          enddo
        enddo
        do i=1,nFreePoints
          ntotsamples=ntotsamples+1
          Prioriphotolimit(ntotsamples)=Freeiphotolimit(i)
        enddo
        call ilimittypestats(ntotsamples,Prioriphotolimit,
     &Priorilimittype,Priornumrubis,Priornumrubp,Priornumtpu)
        if(bestilimittype.gt.0.and.Priorilimittype.ne.bestilimittype)
     &return
!if bestilimittype is specified, we assume the fitting is constained to the limit type specified by bestilimittype
        if(Priorilimittype.ge.3)return
!5, 6, 7 are done with Prioriknowlimit=0. We don't consider cases with only rubp and tpu limitations but no rubisco limitations
        if(Priornumrubis.gt.0.and.Priornumrubis.lt.minimumrubis)return
        if(Priornumrubp.gt.0.and.Priornumrubp.lt.minimumfj)return
        if(Priornumtpu.gt.0.and.Priornumtpu.lt.minimumvt)return
        do i=1,ntotsamples
          Currentiphotolimit(i)=Prioriphotolimit(i)
        enddo
      endif
      Currentilimittype=Priorilimittype
      Currentiknowlimit=Prioriknowlimit
!
!-------------Test Area---------------------------------------------
!      Currentilimittype=1
!      Currentiknowlimit=1
!      do i=1,ntotsamples
!        if(i.le.6)then
!          Currentiphotolimit(i)=1
!        else
!          if(i.ge.16.and.i.le.26)then
!            Currentiphotolimit(i)=2
!          else
!            Currentiphotolimit(i)=3
!          endif
!        endif
!      enddo
!-------------------------------------------------------------------
      call DoUnivPhotoFit()
      if(Prioriknowlimit.ne.1.or.Priorilimittype.ge.5)goto 1000
!---------------------------------------------------------
!Enforce the admissibility rule.
!first get the post-fit limit type of each point. (pco2i,anet_obs) should be replaced
!by (pco2i_pred, anet_pred)
      do i=1,ntotsamples
        call leafunivphotosyn(Currentiknowlimit,Currentilimittype,
     &0,aPPFDlf(i),templeaf(i),pco2i_pred(i),po2i(i),chlflphips2(i),
     &term,weitresponses(i:i,1:1),weitresponses(i:i,1:1),
     &weitresponses(i:i,2:2),weitresponses(i:i,1:1),term1,term2,
     &Postiphotolimit(i),term3,term4,term5,term6,term7,term8,term9)
      enddo
      j=0
      do i=1,ntotsamples
        if(Postiphotolimit(i).ne.Currentiphotolimit(i))j=j+1
      enddo
!if j = 0, the fitting is admissible so go to the wrapup
      if(j.eq.0)goto 1000
      call ilimittypestats(ntotsamples,Postiphotolimit,
     &Postilimittype,Postnumrubis,Postnumrubp,Postnumtpu)
!if minimum number of points is not satisfied, go to penality fit directly.
      if(Postnumrubis.gt.0.and.Postnumrubis.lt.minimumrubis)goto 500
      if(Postnumrubp.gt.0.and.Postnumrubp.lt.minimumfj)goto 500
      if(Postnumtpu.gt.0.and.Postnumtpu.lt.minimumvt)goto 500
!check to see if the fit oscillates.
      Currentilimittype=Postilimittype
      do i=1,ntotsamples
        Currentiphotolimit(i)=Postiphotolimit(i)
      enddo
      call DoUnivPhotoFit()
      do i=1,ntotsamples
        call leafunivphotosyn(Currentiknowlimit,Currentilimittype,
     &0,aPPFDlf(i),templeaf(i),pco2i_pred(i),po2i(i),chlflphips2(i),
     &term,weitresponses(i:i,1:1),weitresponses(i:i,1:1),
     &weitresponses(i:i,2:2),weitresponses(i:i,1:1),term1,term2,
     &Postiphotolimit(i),term3,term4,term5,term6,term7,term8,term9)
      enddo
      j=0
      do i=1,ntotsamples
        if(Postiphotolimit(i).ne.Prioriphotolimit(i))j=j+1
      enddo
      if(j.eq.0)then
!Osicillation. Treat osicillating points as co-limited
        k=ntotsamples
        do i=1,ntotsamples
          if(Currentiphotolimit(i).ne.Prioriphotolimit(i))then
            k=k+1
            Currentiphotolimit(k)=Currentiphotolimit(i)
            aPPFDlf(k)=aPPFDlf(i)
            templeaf(k)=templeaf(i)
            po2i(k)=po2i(i)
            pco2i(k)=pco2i(i)
            anet_obs(k)=anet_obs(i)
            chlflphips2(k)=chlflphips2(i)
            Currentiphotolimit(i)=Prioriphotolimit(i)
          endif
        enddo
        call ilimittypestats(k,Currentiphotolimit,
     &Currentilimittype,Currentnumrubis,Currentnumrubp,Currentnumtpu)
        i=ntotsamples
        ntotsamples=k
        call DoUnivPhotoFit()
        sumsquare=sumsquare*dble(i)/dble(k)
        ntotsamples=i
        goto 1000
      else
!no osicillation
        Currentilimittype=Priorilimittype
        do i=1,ntotsamples
          Currentiphotolimit(i)=Prioriphotolimit(i)
        enddo
      endif
!-------------Penalty function fit-------------------------------------------
500   Currentiknowlimit=2
      call DoUnivPhotoFit()
!-------------Wrap up--------------------------------------------------------
1000  if(Prioriknowlimit.eq.0.and.Priorilimittype.le.4)then
        call ilimittypestats(ntotsamples,Postiphotolimit,
     &Postilimittype,Postnumrubis,Postnumrubp,Postnumtpu)
        if(Postnumrubis.gt.0.and.Postnumrubis.lt.minimumrubis-1)
     &sumsquare=1.0d+10
        if(Postnumrubp.gt.0.and.Postnumrubp.lt.minimumfj-1)
     &sumsquare=1.0d+10
        if(Postnumtpu.gt.0.and.Postnumtpu.lt.minimumvt-1)
     &sumsquare=1.0d+10
      endif
      term=1.0d0+(subbestsumsquare(Priorilimittype)-sumsquare)
      if(term.gt.1.0d0)then
        subbestsumsquare(Priorilimittype)=sumsquare
        do i=1,ntotunivparams
          subbestunivparams(i,Priorilimittype)=univparams(i)
        enddo
        do i=1,ntotsamples
          if(Prioriknowlimit.eq.0)then
            subbestiphotolimit(i,Priorilimittype)=Postiphotolimit(i)
          else
            subbestiphotolimit(i,Priorilimittype)=Prioriphotolimit(i)
          endif
        enddo
      endif
      return
      end subroutine UnivPhotoFit
!&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

!&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 
      subroutine DoUnivPhotoFit()
      implicit none
      include '../testarea/LeafGasParams.h'
      include '../testarea/LeafGasHybridFit.h'
      integer i,ndim,k,j,iderivative,iwrong,jnon
      double precision beta(20),sumsquare0,beta0(20),sumsquarecp,
     &betacp(20),ftol,xtol,shortx(maxobs,4),shorty(maxobs,2),ran2,
     &ftol_relax
      parameter(ftol=1.0d-7,xtol=1.0d-7)
      external funkmin_UnivPhotoFit,f1dim_UnivPhotoFit,
     &FCN_UnivPhotoFit,ff_pikaia
!find out which parameters to optimize
      call UnivParamsAlloc(1)
      ndim=0
      do i=1,ntotunivparams
        univparams(i)=subbestunivparams(i,Currentilimittype)
        if(ifixunivparams(i).eq.1)then
          ndim=ndim+1
          beta(ndim)=univparams(i)
          betamin(ndim)=univparamsmin(i)
          betamax(ndim)=univparamsmax(i)
        endif
      enddo
      isitbounded=1
      call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
      do i=1,ndim
        beta0(i)=beta(i)
      enddo
      sumsquare0=sumsquare
      ftol_relax=ftol
      k=0
      if(subbestsumsquare(Currentilimittype).gt.1.0d+9)then
        jnon=0
        ftol_relax=ftol*100.0d0
      endif
30    call nongradopt(ndim,funkmin_UnivPhotoFit,f1dim_UnivPhotoFit,
     &beta,betamin,betamax,ftol_relax,sumsquare)
      call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
      if((sumsquare+1.0d0).eq.sumsquare.or.sumsquare.gt.sumsquare0)then
        do i=1,ndim
          beta(i)=beta0(i)
        enddo
        sumsquare=sumsquare0
      else
        if((sumsquare0-sumsquare).gt.ftol_relax)then
!reset the counter for arriving at a better minimum
          k=0
        else
!if the same minimum is found, increment the counter
          k=k+1
        endif
        do i=1,ndim
          beta0(i)=beta(i)
        enddo
        sumsquare0=sumsquare
      endif
      if(subbestsumsquare(Currentilimittype).gt.1.0d+9)then
        jnon=jnon+1
!for the first run, try different initial guesses
        if(jnon.lt.100.and.k.lt.5)then
          if(ran2().gt.0.7d0)then
            do i=1,ndim
              beta(i)=betamin(i)+ran2()*(betamax(i)-betamin(i))
            enddo
          else
            do i=1,ndim
              if(ran2().gt.0.5d0)then
                beta(i)=beta(i)+(ran2()**(3.0d0/dble(k+1)))*
     &(betamax(i)-beta(i))
              else
                beta(i)=beta(i)-(ran2()**(3.0d0/dble(k+1)))*
     &(beta(i)-betamin(i))
              endif
            enddo
          endif
          call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
          goto 30
        else
          if((ftol_relax-ftol).gt.ftol)then
            ftol_relax=ftol
            goto 30
          endif
        endif
        call RepeatCompassSearch(ndim,beta,sumsquare,betamin,
     &betamax,funkmin_UnivPhotoFit,f1dim_UnivPhotoFit,xtol)
        call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
        if((sumsquare+1.0d0).eq.sumsquare.or.sumsquare.gt.sumsquare0)
     &then
          do i=1,ndim
            beta(i)=beta0(i)
          enddo
          sumsquare=sumsquare0
        endif
        do i=1,ndim
          betacp(i)=(beta(i)-betamin(i))/(betamax(i)-betamin(i))
        enddo
        sumsquarecp=sumsquare
        isitbounded=0
        call pikaia(ff_pikaia,ndim,gacontrol,betacp,sumsquarecp,i)
        isitbounded=1
        if(i.eq.0)then
          do i=1,ndim
            betacp(i)=betamin(i)+betacp(i)*(betamax(i)-betamin(i))
          enddo
          call funkmin_UnivPhotoFit(ndim,betacp,sumsquarecp)
        else
          do i=1,ndim
            betacp(i)=beta(i)
          enddo
          sumsquarecp=sumsquare
        endif
        if((sumsquarecp+1.0d0).ne.sumsquarecp.and.
     &sumsquare.gt.sumsquarecp)then
          do i=1,ndim
            beta(i)=betacp(i)
          enddo
          sumsquare=sumsquarecp
        endif
        do i=1,ndim
          beta0(i)=beta(i)
        enddo
        sumsquare0=sumsquare
      else
        return
      endif
      iderivative=0
      if(ifitmode.lt.0)then
        iwrong=0
      else
        iwrong=1
      endif
      isitbounded=1
      k=ifitmode
      ifitmode=-1
!ifitmode: =-2, ordinary fitting with pco2i calculated as a function of anet
!ifitmode: =-1, ordinary fitting with anet calculated as a function of pco2i
!ifitmode: =1, orthogonal fitting with anet calculated as a function of pco2i
!ifitmode: =2, orthogonal fitting with pco2i calculated as a function of anet
!for odr_leastsquare, only the predicted value of the response variable is needed, i.e., the cost function value is not needed.
!also, only anet as a function of CO2i is considered (not the other way around) because odr_leastsquare cannot handle the situation
!co2i as a function of anet for tpu limitation when alpha=0
      i=1
      if(ntotphips2.ge.1)i=2
      j=4
      if(Currentiknowlimit.eq.-1)then
!fluorescence only fit. chlflphisi2 becomes a forcing variable
        i=1
        j=5
      endif
      call odr_leastsquare(ndim,FCN_UnivPhotoFit,beta,ntotsamples,
     &forcings(1:ntotsamples,1:j),j,responses(1:ntotsamples,1:i),i,
     &weitforcings(1:ntotsamples,1:j),weitresponses(1:ntotsamples,1:i),
     &iderivative,shortx(1:ntotsamples,1:j),shorty(1:ntotsamples,1:i),
     &sumsquare,iwrong)
      isitbounded=1
      ifitmode=k
!after odr_leastsquare, forcing variables are destroyed. restore to the origninals
      do i=1,ntotsamples
        pco2i(i)=pco2i_ori(i)
        aPPFDlf(i)=aPPFDlf_ori(i)
        templeaf(i)=templeaf_ori(i)
        po2i(i)=po2i_ori(i)
        chlflphips2(i)=chlflphips2_ori(i)
      enddo
      call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
      if((sumsquare+1.0d0).eq.sumsquare.or.sumsquare.gt.sumsquare0)then
        do i=1,ndim
          beta(i)=beta0(i)
        enddo
        sumsquare=sumsquare0
      endif
      k=0
      do i=1,ndim
        if(beta(i).lt.betamin(i))k=1
        if(beta(i).gt.betamax(i))k=1
      enddo
      if(k.eq.1)then
        do i=1,ndim
          betacp(i)=(beta(i)-betamin(i))/(betamax(i)-betamin(i))
        enddo
        isitbounded=0
        call pikaia(ff_pikaia,ndim,gacontrol,betacp,sumsquare,i)
        do i=1,ndim
          beta(i)=betamin(i)+betacp(i)*(betamax(i)-betamin(i))
        enddo
        isitbounded=1
        call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
      endif
      j=0
100   jnon=0
105   sumsquare0=sumsquare
      do i=1,ndim
        beta0(i)=beta(i)
      enddo
      call nongradopt(ndim,funkmin_UnivPhotoFit,f1dim_UnivPhotoFit,
     &beta,betamin,betamax,ftol,sumsquare)
      call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
      if(jnon.le.2.and.(sumsquare0-sumsquare).gt.ftol)then
        jnon=jnon+1
        goto 105
      endif
      if(sumsquare.eq.sumsquare0)goto 110
      if(dabs(sumsquare).le.dabs(sumsquare0))then
      else
        if(dabs(sumsquare).gt.1.0d+20)then
!in case of infinity (division by zero)
          do i=1,ndim
            beta(i)=beta0(i)
          enddo
          sumsquare=sumsquare0
        else
!designed this way to avoid sumsquare='NAN' 
          do i=1,ndim
            beta(i)=beta0(i)
          enddo
          sumsquare=sumsquare0
        endif
      endif
      sumsquarecp=sumsquare
      do i=1,ndim
        betacp(i)=beta(i)
      enddo
      call RepeatCompassSearch(ndim,betacp,sumsquarecp,betamin,
     &betamax,funkmin_UnivPhotoFit,f1dim_UnivPhotoFit,xtol)
      call funkmin_UnivPhotoFit(ndim,betacp,sumsquarecp)
      if(sumsquare.eq.sumsquarecp)goto 110
      if(dabs(sumsquarecp).lt.dabs(sumsquare))then
        do i=1,ndim
          beta(i)=betacp(i)
        enddo
        sumsquare=sumsquarecp
      endif
      j=j+1
      if(j.le.2.and.dabs(sumsquare-sumsquare0).gt.ftol)goto 100
!
!------------------------------------------------------
110   call funkmin_UnivPhotoFit(ndim,beta,sumsquare)
      return
      END subroutine DoUnivPhotoFit