, Y_] = solver_4_2_5( dx, dy, dt, slices )
    f_ = @(X, Y)( zeros(size(X)) );
    F_ = @(X, Y, t)( zeros(size(X)) );
    g_0t = @(W, t)( sin(t) .* sin(pi * W) );
    g_1t = @(W, t)( zeros(size(W)) );
    nu = 1;
    slices_id = round(slices / dt);
</pre><pre>     X = round(1 / dx);
     Y = round(1 / dy);
     x = 1; y = 1;
     Mx = x * X; My = y * Y;</pre><pre>     rx = nu * dt / dx / dx;
     ry = nu * dt / dy / dy;</pre><pre>     x_ = 0 : dx : x;
     y_ = 0 : dy : y;
     [X_, Y_] = meshgrid(x_, y_);<