mpi-io | 易学教程

Using MPI-IO to write Fortran-formatted files

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问题 I am trying to save a solution using the OVERFLOW-PLOT3D q-file format (defined here: http://overflow.larc.nasa.gov/files/2014/06/Appendix_A.pdf). For a single grid, it is basically, READ(1) NGRID READ(1) JD,KD,LD,NQ,NQC READ(1) REFMACH,ALPHA,REY,TIME,GAMINF,BETA,TINF, & IGAM,HTINF,HT1,HT2,RGAS1,RGAS2, & FSMACH,TVREF,DTVREF READ(1) ((((Q(J,K,L,N),J=1,JD),K=1,KD),L=1,LD),N=1,NQ) All of the variables are double precision numbers, excepts for NGRID, JD, KD, LD, NQ, NQC and IGAM which are

Using MPI-IO to write Fortran-formatted files

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MPI_ERR_BUFFER when performing MPI I/O

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问题 I am testing MPI I/O. subroutine save_vtk integer :: filetype, fh, unit integer(MPI_OFFSET_KIND) :: pos real(RP),allocatable :: buffer(:,:,:) integer :: ie if (master) then open(newunit=unit,file="out.vtk", & access='stream',status='replace',form="unformatted",action="write") ! write the header close(unit) end if call MPI_Barrier(mpi_comm,ie) call MPI_File_open(mpi_comm,"out.vtk", MPI_MODE_APPEND + MPI_MODE_WRONLY, MPI_INFO_NULL, fh, ie) call MPI_Type_create_subarray(3, int(ng), int(nxyz),

MPI IO Writing a file when offset is not known

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问题 I want to use MPI IO to write files. The processes is in a while loop and it calls a function which generates random amount of data. I want to write this data to a single file. How can I accomplish this? 回答1: It might help you: http://social.microsoft.com/Forums/en-US/47b99479-37d9-43a4-b1e3-90efd3d52c0a/can-different-mpi-processes-write-data-in-one-file-with-different-offset?forum=windowshpcmpi But maybe you ll need to pass a variable which contains the start point of every process.. 回答2: in

MPI I/O, mix of single- and multiple-process output

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问题 I need an MPI C code to write data to a binary file via MPI I/O. I need process 0 to write a short header, then I need the whole range of processes to write their own pieces of the array indicated by the header. Then I need process 0 to write another header, followed by all processes writing their pieces of the next array, etc. I came up with the following test code which actually does what I want. No one will be more surprised about that than me. My question is, I am new at MPI I/O. So am I

MPI-IO: MPI_File_Set_View vs. MPI_File_Seek

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问题 I encounter a problem when trying to write a file with MPI-IO, in Fortran 90. If I do the following, using MPI_File_Set_View program test implicit none include "mpif.h" integer :: myrank, nproc, fhandle, ierr integer :: xpos, ypos integer, parameter :: loc_x=10, loc_y=10 integer :: loc_dim integer :: nx=2, ny=2 real(8), dimension(loc_x, loc_y) :: data, data_read integer :: written_arr integer, dimension(2) :: wa_size, wa_subsize, wa_start integer :: int_size, double_size integer(kind=MPI

Is it possible to write with several processors in the same file, at the end of the file, in an ordonated way?

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问题 I have 2 processors (this is an example), and I want these 2 processors to write in a file. I want them to write at the end of file, but not in a mixed pattern, like that : [file content] proc0 proc1 proc0 proc1 proc0 proc1 (and so on..) I'd like to make them write following this kind of pattern : [file content] proc0 proc0 proc0 proc1 proc1 proc1 (and so on..) Is it possible? If so, what's the setting to use? 回答1: The sequence in which your processes have outputs ready to report is,

How to use and interpret MPI-IO Error codes?

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问题 #include <stdio.h> #include <iostream> #include <Windows.h> #include <C:\Program Files\Microsoft MPI\Inc\mpi.h> using namespace std; #define BUFSIZE 128 int main (int argc, char *argv[]) { int err; int rank; int size; double start_time = 0.0; double end_time; MPI_Comm comm = MPI_COMM_WORLD; MPI_File file; char cbuf[BUFSIZE]; for(int i = 0; i < BUFSIZE; i++) { cbuf[i] = 'a' + i; } if(err = MPI_Init(&argc, &argv)) { printf("%s \n", "Error! MPI is halted!"); MPI_Abort(comm, err); } MPI_Comm_size

How to use and interpret MPI-IO Error codes?

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#include <stdio.h> #include <iostream> #include <Windows.h> #include <C:\Program Files\Microsoft MPI\Inc\mpi.h> using namespace std; #define BUFSIZE 128 int main (int argc, char *argv[]) { int err; int rank; int size; double start_time = 0.0; double end_time; MPI_Comm comm = MPI_COMM_WORLD; MPI_File file; char cbuf[BUFSIZE]; for(int i = 0; i < BUFSIZE; i++) { cbuf[i] = 'a' + i; } if(err = MPI_Init(&argc, &argv)) { printf("%s \n", "Error! MPI is halted!"); MPI_Abort(comm, err); } MPI_Comm_size(comm, &size); MPI_Comm_rank(comm, &rank); if(rank == 0) { start_time = MPI_Wtime(); } err = MPI_File