
mesh
   rectilinear
    ny = 126
    nz = 225
    nx = 1
    bx = 1
    by = 1
    bz = 1
    gmin = -18 -12.7 -22.5
    gmax = 52 12.7 22.5
   end

   user defined element density, i
    "
    field = 3;
    "
   end

   user defined element density, j
    "
    field = 3;
    if (coord > 0.5)    { field = 3*exp( -0.1*(coord-0.5)); }
    if (coord <-0.5)    { field = 3*exp(0.1*( coord+0.5)); }
    "
   end

   user defined element density, k
    "
    field = 3;
    if (coord > 0.5)    { field = 3*exp( -0.1*(coord-0.5)); }
    if (coord <-0.5)    { field = 3*exp(0.1*( coord+0.5)); }
    "
   end
end
