mpi_file.cpp

Jacobi_MPI. ln2 & pi 的计算,基于Romberg and Simpson. MPI_File.

#define MPICH_SKIP_MPICXX
#include "mpi.h"
#include <stdio.h>
#pragma comment(lib,"mpi.lib")
#define n 4
void main()
{
	double *buff={0},*a;
	MPI_Init(0,0);
	MPI_Status sta;
	MPI_File fh;
	MPI_File_open(MPI_COMM_WORLD,"data.txt",MPI_MODE_CREATE+MPI_MODE_WRONLY,MPI_INFO_NULL,&fh);
	MPI_File_write_at(fh,0,buff,n*n,MPI_DOUBLE,&sta);
	MPI_File_close(&fh);
	MPI_Read_at(fh,0,a,n*n,MPI_DOUBLE,&sta); //从文件中读数据到数组a 
	//int MPI_File_read_at(MPI_File fh, MPI_Offset offset, void * buf, int count,MPI_Datatype datatype, MPI_Statye * status)
}