129                      nnnx
129                      nnny
2                       idgrid (nx=(nnnx-1)/idgrid+1,...)
8                      ndmnx
1                       ndmny
-----------------------------------
2                       ndiff: choose the coef a(x,y)
10.0                    c4diff  (if mod(ndiff,10)=3)
0.0                     c4react (=c)
20.0                    art_react (for coarse grid solution)
0                       id_point_src(=1:point source, else:true rhs)
-----------------------------------
5                       npcol: number of columns in print out(<=5)
1.0e-2                  tol
1.0e-5                  tol2grid
2                       level
500                     itmax
50                      itmax2grid
0                       id_sgs (=1:Symm.Gauss.Seidal, else:Gauss.Seidal)
5                       itmax_smooth
1                       id_auto_smooth (=1: itmax_smooth=idgrid+2)
-----------------------------------
0.d0                    ax
1.d0                    bx
0.d0                    ay
1.d0                    by
