! $Header$

! ================================================================================

  IMPLICIT NONE

  ! --------------------------------------------------------------------------------

  ! Inputs:

  ! ND----------: Number of vertical levels

  ! R--------ND-: Domain-averaged mixing ratio of total water

  ! RS-------ND-: Mean saturation humidity mixing ratio within the gridbox

  ! QSUB-----ND-: Mixing ratio of condensed water within clouds associated

  ! with SUBGRID-SCALE condensation processes (here, it is

  ! predicted by the convection scheme)

  ! Outputs:

  ! PTCONV-----ND-: Point convectif = TRUE

  ! RATQSC-----ND-: Largeur normalisee de la distribution

  ! CLDF-----ND-: Fraction nuageuse

  ! --------------------------------------------------------------------------------

  INTEGER klon, nd

  REAL r(klon, nd), rs(klon, nd), qsub(klon, nd)

  LOGICAL ptconv(klon, nd)

  REAL ratqsc(klon, nd)

  REAL cldf(klon, nd)

  ! -- parameters controlling the iteration:

  ! --    nmax    : maximum nb of iterations (hopefully never reached)

  ! --    epsilon : accuracy of the numerical resolution

  ! --    vmax    : v-value above which we use an asymptotic expression for

  ! ERF(v)

  INTEGER nmax

  PARAMETER (nmax=10)

  PARAMETER (epsilon=0.02, vmax0=2.0)

  REAL min_mu, min_q

  PARAMETER (min_mu=1.E-12, min_q=1.E-12)

  INTEGER i, k, n, m

  REAL zu2, zv2

  REAL dist, fprime, det

  REAL pi, u, v, erfcu, erfcv

  REAL xx1, xx2

  REAL erf, hsqrtlog_2, v2

  REAL sqrtpi, sqrt2, zx1, zx2, exdel

  ! lconv = true si le calcul a converge (entre autre si qsub < min_q)

  ! cdir arraycomb

  ! cdir end arraycomb

  pi = acos(-1.)

  sqrtpi = sqrt(pi)

  sqrt2 = sqrt(2.)

  hsqrtlog_2 = 0.5*sqrt(log(2.))

      ! enddo ! vector

      ! ***          There is no subgrid-scale condensation;        ***

      ! ***   the scheme becomes equivalent to an "all-or-nothing"  ***

      ! ***             large-scale condensation scheme.            ***

      ! ***     Some condensation is produced at the subgrid-scale       ***

      ! ***                                                              ***

      ! ***       PDF = generalized log-normal distribution (GNO)        ***

      ! ***   (k<0 because a lower bound is considered for the PDF)      ***

      ! ***                                                              ***

      ! ***  -> Determine x (the parameter k of the GNO PDF) such        ***

      ! ***  that the contribution of subgrid-scale processes to         ***

      ! ***  the in-cloud water content is equal to QSUB(K)              ***

      ! ***  (equations (13), (14), (15) + Appendix B of the paper)      ***

      ! ***                                                              ***

      ! ***    Here, an iterative method is used for this purpose        ***

      ! ***    (other numerical methods might be more efficient)         ***

      ! ***                                                              ***

      ! ***          NB: the "error function" is called ERF              ***

      ! ***                 (ERF in double precision)                   ***

      ! On commence par eliminer les cas pour lesquels on n'a pas

      ! suffisamment d'eau nuageuse.

      ! do i=1,klon ! vector

        ! Rien on a deja initialise

      ELSE

        ! --  roots of equation v > vmax:

        ELSE

        END IF

      END IF

    END DO ! vector

    ! ----------------------------------------------------------------------

    ! Debut des nmax iterations pour trouver la solution.

    ! ----------------------------------------------------------------------

              ! -- use asymptotic expression of erf for u and v large:

              ! ( -> analytic solution for xx )

                ! print*,'AUX(',i,',',k,')<0',aux(i),delta(i),beta(i)

              END IF

              dist = 0.0

            ELSE

              ! -- erfv -> 1.0, use an asymptotic expression of erfv for v

              ! large:

              ! !!! ATTENTION : rajout d'un seuil pour l'exponentiel

            END IF ! ABS(u)

          ELSE

            ! -- general case:

            block = erfcv

            zv2 = v2

              ! print*,'ATTENTION !!! xx(',i,') =', xx(i)

              ! print*,'ATTENTION !!! klon,ND,R,RS,QSUB,PTCONV,RATQSC,CLDF',

              ! .klon,ND,R(i,k),RS(i,k),QSUB(i,k),PTCONV(i,k),RATQSC(i,k),

              ! .CLDF(i,k)

              ! print*,'ATTENTION !!! zu2 zv2 =',zu2(i),zv2(i)

              zu2 = 20.

              zv2 = 20.

              fprime = 0.

            ELSE

              fprime = 2./sqrtpi/xx(i)/(erfcv*erfcv)* &

            END IF

          END IF ! x

          ! -- test numerical convergence:

          ! if (beta(i).lt.1.e-10) then

          ! print*,'avant test ',i,k,lconv(i),u(i),v(i),beta(i)

          ! stop

          ! endif

            ! print*,'avant test fprime<.e-11 '

            ! s        ,i,k,lconv(i),u(i),v(i),beta(i),fprime(i)

            ! print*,'klon,ND,R,RS,QSUB',

            ! s        klon,ND,R(i,k),rs(i,k),qsub(i,k)

          END IF

            ! print*,'v-u **2',(v(i)-u(i))**2

            ! print*,'exp v-u **2',exp((v(i)-u(i))**2)

            ! borne pour l'exponentielle

          ELSE

          END IF

          ! print*,'apres test ',i,k,lconv(i)

        END IF ! lconv

      END DO ! vector

      ! ----------------------------------------------------------------------

      ! Fin des nmax iterations pour trouver la solution.

    END DO ! n

    ! ----------------------------------------------------------------------

  END DO

  ! K

END SUBROUTINE clouds_gno