给定一个椭圆方程，我们先找出这个方程的拉氏函数，用差分代替微分，得到离散的拉氏函数。

At first we can get the Lagrangian function from the elliptic equation, then replace differential coefficient by difference and get the discrete Lagrangian function.

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给定一个椭圆方程，我们先找出这个方程的拉氏函数，用差分代替微分，得到离散的拉氏函数。

At first we can get the Lagrangian function from the elliptic equation, then replace differential coefficient by difference and get the discrete Lagrangian function.

youdao