Re: [OMPI users] Open MPI access the same file in parallel ?

Thanks, I only need to read the file. And, all processes only to read the file only once. But, the file is about 200MB. But, my code is C++. Does Open MPI support this ? thanks From: solarbik...@gmail.com List-Post: users@lists.open-mpi.org Date: Wed, 9 Mar 2011 20:57:03 -0800 To: us...@open

Re: [OMPI users] Open MPI access the same file in parallel ?

It not about MPI but rather your system. Can your system read the same file multiple times? Can you open the same file multiple times? The simplest way to answer your question is to write a simple MPI program to test this. On Wed, Mar 9, 2011 at 9:08 PM, Jack Bryan wrote: > Thanks, > > I onl

Re: [OMPI users] Open MPI access the same file in parallel ?

Hi, You can do that with C++ also. Just for fun of it, I produced a little program for that; each process reads the whole file and print the content to stdout. I hope this helps: #include #include #include #include using namespace std; int main (int argc, char* argv[]) { int rank

Re: [OMPI users] Open MPI access the same file in parallel ?

Hi, thanks for your code. I have test it with a simple example file. It works well without any conflict of parallel accessing the same file. Now, I am using CPLEX (an optimization model solver) to load a model data file, which can be 200 MBytes. CPLEX.importModel(modelName, dataFileName) ; I d

Re: [OMPI users] Open MPI access the same file in parallel ?

On 3/9/2011 8:57 PM, David Zhang wrote: Under my programming environment, FORTRAN, it is possible to parallel read (using native read function instead of MPI's parallel read function). Although you'll run into problem when you try to parallel write to the same file. If your Fortran compiler/l

Re: [OMPI users] Open MPI access the same file in parallel ?

Hi Jack, cplex.importModel(model, problemFile) basically reads the problem from "problemFile" and add its content to "model". So, I do not see any problem calling that in your code for each process. The best way is just to try it out and let us know how it goes. With best regards, -Belaid.

Re: [OMPI users] Open MPI access the same file in parallel ?

thanks I am using GNU mpic++ compiler. Does it can automatically support accessing a file by many parallel processes ? thanks > Date: Wed, 9 Mar 2011 22:54:18 -0800 > From: n...@aol.com > To: us...@open-mpi.org > Subject: Re: [OMPI users] Open MPI access the same file in parallel ? > > On 3/

Re: [OMPI users] Open MPI access the same file in parallel ?

On 3/9/2011 11:05 PM, Jack Bryan wrote: thanks I am using GNU mpic++ compiler. Does it can automatically support accessing a file by many parallel processes ? It should follow the gcc manual, e.g. http://www.gnu.org/s/libc/manual/html_node/Opening-Streams.html I think you want *opentype to e

[OMPI users] Understanding the buffering of small messages with tcp network

Dear all, I would like you to ask for a topic that there are already many questions but I am not familiar a lot with it. I want to understand the behaviour of an application where there are many messages less than 64KB (eager mode) and I use TCP network. I am trying to understand in order to

Re: [OMPI users] Two Instances of Same Process Rather Than Two SeparateProcesses

LAM/MPI is dead; all the developers (including me) moved to Open MPI years ago (literally). Most of LAM's good ideas have been absorbed into Open MPI. Switching from LAM to Open MPI is theoretically pretty easy - both use the same-named wrapper compilers (mpicc, mpif77, etc). You should be ab

Re: [OMPI users] Number of processes and spawn

Hi Ralph, I did a chekout of the 22794 revision with svn. I've download and installed (with the default configuration) in my /home folder: - m4 version 1.4.16 - autoconf version 2.68 - automake version 1.11 - libtool version 2.2.6b I've modifyed my CSHRC to export the following: setenv PATH /home/

Re: [OMPI users] Number of processes and spawn

This usually means you didn't install the GNU auto tools properly. Check the HACKING file in the top-level directory for specific instructions on how to install the Autotools. On Mar 10, 2011, at 7:50 AM, Federico Golfrè Andreasi wrote: > > Hi Ralph, > > I did a chekout of the 22794 revision

[OMPI users] v1.5.2 release is missing the new "affinity" MPI extension

We realized late yesterday that the v1.5.2 release is missing the new "affinity" MPI extension (that provides the OMPI_Affinity_str() function for MPI applications), even though it was specifically mentioned in the 1.5.2 NEWS and README files. Oops! We'll be releasing 1.5.3 shortly; it will in

Re: [OMPI users] multi-threaded programming

On Mar 8, 2011, at 12:34 PM, Eugene Loh wrote: > Let's say you have multi-threaded MPI processes, you request > MPI_THREAD_MULTIPLE and get MPI_THREAD_MULTIPLE, and you use the self,sm,tcp > BTLs (which have some degree of threading support). Is it okay to have an > [MPI_Isend|MPI_Irecv] on on

[OMPI users] QLogic Infiniband : Run switch from ib0 to eth0

Hello, We add recently enhanced our network with Infiniband modules on a six node cluster. We have install all OFED drivers related to our hardware We have set network IP like following : - eth : 192.168.1.0 / 255.255.255.0 - ib : 192.168.70.0 / 255.255.255.0 After first tests all seems good. I

[OMPI users] OPEN MPI tutorials depreciated!

Hi All, I am newbie in open-mpi. I am using ubuntu 10.04 machine and installed openmpi from reps. When i read readme docs mentioning like this If you are looking for a comprehensive MPI tutorial, these samples are not enough. An excellent MPI tutorial is available here: http://webct.ncs

Re: [OMPI users] OPEN MPI tutorials depreciated!

Looks like it has moved here: http://www.citutor.org/ On Mar 10, 2011, at 2:49 PM, Abdul Rahman Riza wrote: > Hi All, > > I am newbie in open-mpi. I am using ubuntu 10.04 machine and installed > openmpi from reps. When i read readme docs mentioning like this > > If you are looking for a