[mpich-discuss] reading data into a parallel program

[Jayesh Krishna]

Hi,
 In your case it looks like you might be better off reading from one MPI process and broadcasting to others.

Regards,
Jayesh
----- Original Message -----
From: Prashanth <prashanth.dumpuri at gmail.com>
To: Jayesh Krishna <jayesh at mcs.anl.gov>, mpich-discuss at mcs.anl.gov
Sent: Tue, 07 Dec 2010 11:10:07 -0600 (CST)
Subject: Re: [mpich-discuss] reading data into a parallel program

Jayesh,
  Thanks for getting back to me. I'm not using MPI-IO functions. My datasets
are unstructured grids and I have to use another toolkit (VTK) to read the
files. I can store them in the binary format and they shouldn't be more than
a few megabytes.
  My MPI processes are launched after i read the data and every processor
requires knowledge of the complete dataset (in other words i cannot
partition the data and split it across the available processors). Hope I
answered your question correctly.
   So, given this should I let all the nodes read the input files?
Thanks
Prashanth

On Tue, Dec 7, 2010 at 10:45 AM, Jayesh Krishna <jayesh at mcs.anl.gov> wrote:

> Hi,
>  This will depend on how much data is read and where your MPI processes are
> launched. Are you using MPI-IO functions (like MPI_File_read_all()) for
> reading the data ?
>
> Regards,
> Jayesh
> ----- Original Message -----
> From: Prashanth <prashanth.dumpuri at gmail.com>
> To: mpich-discuss at mcs.anl.gov
> Sent: Mon, 06 Dec 2010 10:44:53 -0600 (CST)
> Subject: [mpich-discuss] reading data into a parallel program
>
> All,
>   I have a main program that reads input data from files and 3
> filters/classes instantiated within the main program that process the
> datasets. I have parallelized 2 of those 3 classes (using MPICH2). Is it
> faster to read data on the root processor and then broadcast it to all the
> child nodes or should I let all the nodes read the data?
>    I'm running my main program on a Windows XP machine with an Intel Quad
> core processor.
> Thanks
> Prashanth
>
>