/***************************************************************************
                 module classe solsor_gc1_x_r.h  -  description
***************************************************************************/
// Julien Brajard
// locean-ipsl.upmc, Paris, April 25, 2011
//===========================================================================
//                          methode forward
forward (YREAL x1, YREAL x2, YREAL x3, YREAL x4, YREAL x5, YREAL x6, YREAL x7, YREAL x8)
{
/*  	1	from	gcx_dynspg_flt		1  i 	j    	  t
     	2	from	gcb_dynspg_flt		1  i 	j    	  t
	3	from	solsor_gc2_x_r		1  i 	j-1  k-1  t
	4	from	solsor_gc2_x_r		1  i-1 	j    k-1  t
	5	from	solsor_gc2_x_r		1  i+1 	j    k-1  t
	6	from	solsor_gc2_x_r		1  i 	j+1  k-1  t
	7	from	solsor_gc2_x_r		1  i 	j    k-1  t
	8       from    solsor_flag             2  NX   NY   k-1  t
} 
output 1 : gcx
oupput 2 : gcr (pour l'arrêt des itérations

*/
  if(Yt==TU)
    {
      YS1=0;
      YS2=0;
    }
  else {
    int t;
    if(Yt==TU+1 && neuler==0)
      t=0;
    else
      t=1;
    
    if (x8==1)
      {
	YS1=x7;
	YS2=0;
      }
    else
      {
	if (Yk==0) {
	  if ( ( (Yi==0) | (Yj==0) ) | ( (Yi==NX-1) | (Yj==NY-1) )) {
	    YS1=0;
	    YS2=0;
	  }
	  else {
	    YS1=x1;
	    YS2=0;
	  } 
	} //Yk=0;
	else {
	  YREAL ztmp,zres;
	  int ishift=Yj%2;
	  if ((Yi+1)%2==ishift) { //! Guess black update
	    ztmp = x2 
	      - gcp(Yi,Yj,0,t) * x3   
	      - gcp(Yi,Yj,1,t) * x4   
	      - gcp(Yi,Yj,2,t) * x5   
	      - gcp(Yi,Yj,3,t) * x6;
	    //     ! Estimate of the residual
	    zres = ztmp - x7;
	    YS2 = zres * gcdmat(Yi,Yj,t) * zres;
	    //               ! Guess update
	    YS1 = sor * ztmp + (1.-sor) * x7;
	  }
	  else
	    {
	      YS2=0;
	      YS1=x7;
	    }
	  
	  
	} // Yk>0
      } //if x8==0
    //if (Yt==TU+1) 
    // printf("%d\t%d\t%d\t%e\t%e (1)\n",Yk,Yj,Yi,YS1,YS2);  
} //Yt>TU
}

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

backward (YREAL x1, YREAL x2, YREAL x3, YREAL x4, YREAL x5, YREAL x6, YREAL x7, YREAL x8) {
/*  	1	from	gcx_dynspg_flt		1  i 	j    	  t
     	2	from	gcb_dynspg_flt		1  i 	j    	  t
	3	from	solsor_gc2_x_r		1  i 	j-1  k-1  t
	4	from	solsor_gc2_x_r		1  i-1 	j    k-1  t
	5	from	solsor_gc2_x_r		1  i+1 	j    k-1  t
	6	from	solsor_gc2_x_r		1  i 	j+1  k-1  t
	7	from	solsor_gc2_x_r		1  i 	j    k-1  t
	8       from    solsor_flag             2  NX   NY   k-1  t
} 
output 1 : gcx
oupput 2 : gcr (pour l'arrêt des itérations

*/
  if(Yt==TU)
    {
   YJ1I1=0;
    }
  else {
    int t;
    if(Yt==TU+1 && neuler==0)
      t=0;
    else
      t=1;
    
    if (x8==1)
      {
	YJ1I7=1;
	//	YS1=x7;
      }
    else
      {
	if (Yk==0) {
	  if ( ( (Yi==0) | (Yj==0) ) | ( (Yi==NX-1) | (Yj==NY-1) )) {
	   
	    //YS1=0;
	    
	  }
	  else {
	    YJ1I1=1;
	    //	    YS1=x1;
	  } 
	} //Yk=0;
	else {
	  //	  YREAL ztmp,zres;
	  int ishift=Yj%2;
	  if ((Yi+1)%2==ishift) { //! Guess black update
	    YREAL dztmpdx2=1;
	    YREAL dztmpdx3=-gcp(Yi,Yj,0,t);
	    YREAL dztmpdx4=-gcp(Yi,Yj,1,t);
	    YREAL dztmpdx5=-gcp(Yi,Yj,2,t);
	    YREAL dztmpdx6=-gcp(Yi,Yj,3,t);	    
	    /*ztmp = x2 
	      - gcp(Yi,Yj,0,t) * x3   
	      - gcp(Yi,Yj,1,t) * x4   
	      - gcp(Yi,Yj,2,t) * x5   
	      - gcp(Yi,Yj,3,t) * x6;*/
   
	    YJ1I2=sor*dztmpdx2;
	    YJ1I3=sor*dztmpdx3;
	    YJ1I4=sor*dztmpdx4;
	    YJ1I5=sor*dztmpdx5;
	    YJ1I6=sor*dztmpdx6;
	    YJ1I7=(1.-sor); 	     	   
//YS1 = sor * ztmp + (1.-sor) * x7;
	  }
	  else
	    {
	      YJ1I7=1;
	      // YS1=x7;
	    }
	  
	  
	} // Yk>0
      } //if x8==0
    //if (Yt==TU+1) 
    // printf("%d\t%d\t%d\t%e\t%e (1)\n",Yk,Yj,Yi,YS1,YS2);  
} //Yt>TU

  /*if (Yi>22 & Yi < 26 & Yj>18 & Yj <21 & Yk==241 & Yt==9) {

 for (int i=0;i<  9;i++) 
    {
      
      for (int j=0;j<2;j++) {
	//	if (Yjac[j][i]>1 & YG1Y_solsor_gx2_x_r>1e-10 ) {
	    printf("gx1 (%d,%d,%d,%d) YG1=%e,YG2=%e(%e)",Yi,Yj,Yk,Yt,YG1Y_solsor_gx2_x_r,YG2Y_solsor_gx2_x_r,(&YG1Y_solsor_gx2_x_r)[1]);
	    printf(" YJ%dI%d=%e\n",j+1,i+1,Yjac[j][i]);
	  }
      }
      }*/
}