利用MPI实现并行化的jacobi算法，同时加入串行实现的算法用于对比 编译：mpicc jacobi.c -o jacobi 运行：mpirun -n nodenum jacobi-Realize the use of MPI-based parallel jacobi algorithm, at the same time serial algorithm is used to realize the contrast compilers: mpicc jacobi.c-o jaco