[mpich-discuss] writing results of a parallel code in a single txt file

[ehsan saei]

yes I use MPI_Isend and MPI_Irecv for simple example I divide a 8*8 matrix between two processes half of the matrix is in process 0 and the other half is in the process 1 now I want to write this matrix on a txt file (all the elements of the matrix on a single file) when I do this I see that the half of the matrix would write on a txt file 
the writing code is:
//myrank shows the process number and istart=0,iend=4 for process 0 and istart=4,iend=8 for process 1
for(i=0;i<2;i++){
if(myrank==i){
ofstream makefile;
makefile.open("A.txt");
for(j=0;j<8;j++){
for(i=istart;i<iend;i++){
makefile<<A[i][j];
}
}
makefile.close();
}
}
On Nov 12, 2011, at 7:07 AM, Jeff Hammond wrote:

> are you using MPI-IO?  if not, i don't see how this question belongs
> on the MPICH discussion email list.
> 
> with the information you have provided, i conclude that you have
> written an incorrect parallel program and not that there is anything
> wrong with MPI.
> 
> jeff
> 
> On Fri, Nov 11, 2011 at 6:59 PM, ehsan saei <shajarian_e at yahoo.com> wrote:
>> Hi all
>> 
>> I want to write a parallel code that do some processes on a matrix after doing the job I want to write the updated matrix on a txt file I do this and my problem is that only the latest workers result that save its matrix on the txt file would save what must I do ?
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> 
> 
> -- 
> Jeff Hammond
> Argonne Leadership Computing Facility
> University of Chicago Computation Institute
> jhammond at alcf.anl.gov / (630) 252-5381
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