/***************************************************************************
                 module classe ta.h  -  description
***************************************************************************/
// Mohamed Berrada
// locean-ipsl.upmc, Paris, April 17, 2009
//===========================================================================
//                          methode forward
forward (YREAL x1,YREAL x2,YREAL x3,YREAL x4,YREAL x5)
{ /*  	1	from	zwisd_trazdf_imp	2  i 	j    k	  t
     	2	from	ta_trazdf_imp		1  i 	j    k+1  t
     	3	from	ta_de_trazdf_imp	1  i 	j    k	  t
     	4	from	zwt_trazdf_imp		1  i 	j    k	  t
     	5	from	ta_c		        1  i 	j    k */
  if(Yt==TU){
    //  if(Yi==28 && Yj==12)
    YS1=x5;
  }
  else{
    if(Yi==0 || Yi==NX-1 || Yj==0 || Yj==NY-1 || Yk==NZ-1){
      YS1=0.;
    }
    else{
      if(Yk==NZ-2)
	YS1= x3/x4*tmask(Yi,Yj,NZ-2);
      else
	YS1=(x3-x1*x2)/x4*tmask(Yi,Yj,NZ-2);
    }
  }
  //
}

//===========================================================================
//                         methode  backward

backward (YREAL x1,YREAL x2,YREAL x3,YREAL x4,YREAL x5)
{
  YJ1I1=0.;     YJ1I2=0.;   YJ1I3=0.;     YJ1I4=0.;   YJ1I5=0.;
  if(Yt==TU){
    YJ1I1=0.;     YJ1I2=0.;   YJ1I3=0.;     YJ1I4=0.;   YJ1I5=0.;
    //#ifdef YE_ta_c
    //if(Yi==28 && Yj==12) 
    YJ1I5=1.;
    //#endif
  }
  else{
    if(Yi==0 || Yi==NX-1 || Yj==0 || Yj==NY-1 || Yk==NZ-1){
      YJ1I1=0.;     YJ1I2=0.;   YJ1I3=0.;     YJ1I4=0.;   YJ1I5=0.;
    }
    else{
      if(Yk==NZ-2){
	YS1= x3/x4*tmask(Yi,Yj,NZ-2);
	YJ1I1=0.;
	YJ1I2=0.;
	YJ1I3=1./x4*tmask(Yi,Yj,NZ-2);  
	YJ1I4=-x3/x4/x4*tmask(Yi,Yj,NZ-2);
	YJ1I5=0.;
      }
      else{
	YJ1I1=-x2/x4*tmask(Yi,Yj,NZ-2);
	YJ1I2=-x1/x4*tmask(Yi,Yj,NZ-2);
	YJ1I3=1./x4*tmask(Yi,Yj,NZ-2);  
	YJ1I4=-(x3-x1*x2)/x4/x4*tmask(Yi,Yj,NZ-2);
	YJ1I5=0.;
      }
    }
  }
  //
  // if( Yi==10 && Yj==10 && Yk==0) printf("YG_ta21(%d)= %24.16e\n",Yt,YG_ta(0,Yi,Yj,Yk,Yt));
  //if(Yt==19 && Yi==10 && Yj==10 && Yk==0) printf("YG_ta20 %24.16e\n",YG_ta(0,Yi,Yj,Yk,Yt));
}

//===========================================================================
//***************************  FIN DU MODULE ta  ****************************