(6) MPI-IO: fileview MPI_File_set_view MPI_File_get_view

最新推荐文章于 2024-09-12 16:29:21 发布

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最新推荐文章于 2024-09-12 16:29:21 发布 · 1.9k 阅读

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#file #basic #null #filter #struct #access

本文详细探讨了MPI-IO中的fileview概念，重点讲解了如何使用MPI_File_set_view和MPI_File_get_view函数进行文件视图的设置和获取。通过实例分析，阐述了fileview在并行I/O中的重要作用，以及如何结合null、filter和struct等元素实现灵活的数据访问模式。

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include"mpi.h"

/**
 * int MPI_File_set_view(MPI_File fh, MPI_Offset disp, MPI_Datatype etype, MPI_Datatype filetype, char * datarep, MPI_Info info);
 * 		etype = basic unit of data access (can be any basic or derived datatype)
 * 		filetype = specifies which portion of the file is visible to the process, filetype can filter the irrelative type
 * 					the filetype is the real datatype viewed for processes
 * 		daterep =  native, internal, or external32
 *    	e.g., MPI_File_set_view(thefile, myrank * BUFSIZE * sizeof(int), MPI_INT, MPI_INT, "native", MPI_INFO_NULL);
 *===================================================================
 *    	after set fileview, each process can write at its view, and does not need to specify the offset
 *    	as long as the file view is not interleaved with other process
 *    	because after fileview, fh is not