利用有限差分法解边值问题时，首先将求解区域分为很多个网格和节点，并用差商代替微商，然后，使区域中的偏微分方程转化为以节点的数值为未知量的差分方程组，最后，解该方程组便可得到各离散点待求的数值解-Using the finite difference method for solving boundary value problem, the solution region is divided into many grid nodes, instead of the derivative with a difference quotient, then, in the area of ​ ​ partial differential equations into differential node values ​ ​ for the unknown quantities equations, and finally, the solution of the equations can be obtained numerical solution of the discrete points unknown