代码：
G1 = 1;
G2 = 1;
G3 = 3;
h = 0.005;
t = 0.005;
ListPlot3D[
RecurrenceTable[{u[i - 2, k + 1] == -u[i - 2, k] +
2 u[i - 1, k + 1] + 2 u[i - 1, k] - 2 u[i + 1, k + 1] -
2 u[i + 1, k] + u[i + 2, k + 1] +
u[i + 2,
k] + (8 h^3 (G3 - G1 - G2))/(u[i + 1, k + 1] + u[i + 1, k] -
u[i - 1, k + 1] - u[i - 1, k]), u[0, k] == E^(-k*t),
u[i, 0] == E^(-i*h), u[-1, k] == (1 - h) E^(-k*t),
u[-2, k] == (1 - 2 h) E^(-k*t)}, u, {i, -2, 200}, {k, 0, 200}]]
报错：

初值错了，要么就是方程错了。你代个i=0进去分析下就明白了。