说明：   Jacobi迭代法求解Poisson方程的MPI并行编程。可以接受参数作为问题剖分大小，能自动根据问题规模选择合适的任务划分（行、列、块）。速度不错。精度及问题函数可以自己在编译前设置。 BY：廖能想
(Jacobi iterative method for solving Poisson equation MPI parallel programming. Acceptable parameters as the issue of partition size, can automatically select the appropriate size according to the issue of separation of tasks (rows, columns, blocks). Good speed. The issue of accuracy and function can be set in the pre-compiler. BY: Liao can think)