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Questions tagged [mpi-io]

MPI/IO provides high performance, portable, parallel I/O interface to high performance, portable, parallel MPI programs

The purpose of MPI/IO is to provide high performance, portable, parallel I/O interface to high performance, portable, parallel MPI programs. Parallel I/O is not a daily bread. Although some supercomputer systems in the past offered parallel disk subsystems, e.g., the Connection Machine CM5 had a Scalable Disk Array, SDA, the Connection Machine CM2 had the Data Vault and IBM SP had PIOFS and today it has GPFS, communication with those peripherals was architecture and operating system dependent.

See the MPI/IO site for more.

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MPIIO write integer based on C++

I want to write the integer b in the output file. I try to provide the address of a, but it only outputs the first several chars, there is not number after the chars. Here is my code: #include #include #include #include…
Mac cchiatooo
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MPI-IO only writes data from one process

For some reason, MPI-IO is only writing the data from one of my processes out to a file. I used MPI_File_open to open the file, MPI_File_set_view to set the view for each process, and MPI_File_write_all to write the data out. When I run the code,…
Mav
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MPI-IO MPI_INTEGER and MPI_DOUBLE_PRECISION give different results

The problem below is Write a 4 * 4 buff array using mpiio. I use 4 cores, so the subarray should be 2 * 2. The problem is that, when I set buff is integer(2,2), and set all the MPI_DOUBLE_PRECISION to MPI_INTEGER, the code works well. However,…
Mac cchiatooo
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The MPI_IO write_all subarray and the component number

I am tring to write a 4 * 4 array using MPI_SET_VIEW and MPI_WRITE_ALL. The xx is a 4 * 4 array and I expect xx = (0,1,2,3; 0,1,2,3; 0,1,2,3; 0,1,2,3) for this code. The globle_size and the local_size equal to 4 and 2. I first create a subarray 2 *…
Mac cchiatooo
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What's wrong with this example using MPI-IO set_view and write_all?

When I try to construct a simple array and write to a output file using MPIIO, the output file is very large and not correct. The simple array 'buff' is 2 * 3 and every element equals to 1. I first create the subarray filetype which is 1 * 1, and…
Mac cchiatooo
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MPI reading simple dataframe or txt file

I have this dataframe: date,AA,BB,CC 2018-01-01 00:00:00,45.73,0.0,1 2018-01-01 01:00:00,44.16,0.0,2 2018-01-01 02:00:00,42.24,0.0,3 2018-01-01 03:00:00,39.29,0.0,5 2018-01-01 04:00:00,36.0,0.0,6 2018-01-01 05:00:00,41.99,0.0,7 2018-01-01…
diedro
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MPI Read file using MPI_Type_create_subarray

I want to using MPI MPI_File_read_all to read a file input.txt which contains binary integers 0,1,2,...,1000. In my implementation, I use MPI_Type_create_subarray to create a 5*5 subarray mysub out of a 10*10 array. Hoping to read following matrix…
Toby Mao
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Synchronise MPI shared file pointers

Is there a standard way to synchronise MPI shared file pointers so that MPI_File_get_position_shared returns the same value on all processes? For example the following program: #include #include #include #include…
Simon Byrne
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how to plot with MPI in a single formatted (readable) file with MPI-IO

I am using MPI in fortran-90 framework. I would like to write in a single file all the data computed from different processors. I would like also to write the data in a readable format and not in the binary one. In this moment, in my program, each…
diedro
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Processes spinning waiting for MPI-IO to sync on MPI_File_open

I have some setup where all processes get a consecutive chunk of work, and I want to save all the output together at the end as a single file, like the following: int start_ind = split_work(mpi_rank, mpi_size), end_ind = split_work(mpi_rank+1,…
aCheese
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collect distributed data using mpi_type_create_subarray

i'm writing an mpi code that needs to write distributed data to single file. when i check subarray function , subarray function works well. But if using file set view function to collect data, file include data proper data and NaN or some trash data…
chan lee
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MPI_FILE_WRITE_ORDERED overwrites previous written data

I have the following code program mpi_io use mpi implicit none integer :: mpierr, whoami, nproc, iout, STATUS(MPI_STATUS_SIZE),charsize integer(kind=mpi_offset_kind):: OFFSET, fs character(len=60) :: dd,de character:: newline =…
ATK
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MPI_File_write C

I have to use MPI to compute value of concentration from a 3D matrix. I divide my matrix in slices depending on the value of the number of proc I will use. I get smaller 3D matrix which work independently but I want that the values of…
Vandeghen Renaud
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Write huge arrays to a single file using MPI-IO with shared file pointer

I'm trying to write several long distributed arrays to a single file using MPI-I/O (OpenMPI implementation) with shared file pointer. I get the following error messages lseek:Invalid argument WRITE FAILED I prepared a simplified code snippet to…
Yury Shkliaryk
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Reading an unformatted stream binary file using MPI I/O in Fortran

I have an unformatted stream binary file of size ~60GB, which I read as follows in my serial code; parameter(nsea=120445) real*4 p(nsea,nsea) open(10,file='my_file.grd' & & ,status='old',access='stream',form='unformatted') …
Seemanth M
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