“…where 𝛿x = (x N+1 −x 0 ) N+1 , N is the internal number of spatial nodes, and x 1 = x 0 + 𝛿x, … , x N = x 0 + N𝛿x, x N+1 = x 0 + (N + 1)𝛿x. Taking N = 19 and using (24) on the grid points x i = i 20 , i = 1, … , N, we get 𝑦 1 , 𝑦 2 , 𝑦 3 , … , 𝑦 N by solving the following system of differential equations after replacing 𝜕 2 𝑦 𝜕x 2 (x i , t) in ( 24) into (23),…”