Questions tagged [openmpi]

Open MPI is an open source implementation of the Message Passing Interface, a library for distributed memory parallel programming.

The Open MPI Project is an open-source implementation of the Message Passing Interface, a standardized and portable message-passing system designed to leverage to computational power of massively parallel, distributed memory computers.

Message passing is one of the distributed memory models most often used, with MPI being the most used message passing API, offering two types of communication between processes: point-to-point or collective. MPI can run in distributed and shared memory architectures.

An application using MPI consists usually of multiple simultaneously running processes, normally on different CPUs, which are able to communicate with each other. Normally, this type of application is programmed using the SPMD model. Nevertheless, most MPI implementations also support the MPMD model.

More information about the MPI standard may be found on the official MPI Forum website, in the official documentation, and in the Open MPI documentation.

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R on slurm: Rmpi and srun

I am using an HPC slurm cluster with Open MPI. The administrators would like everyone to use srun instead of mpirun. I have been using mpirun for years and quasi all discussions online on using R with MPI employ mpirun instead of srun. Are there any…
Chr
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Dynamic nodes in OpenMPI

In MPI, is it possible to add new nodes after it is started? For example, I have 2 computers already running a parallel MPI application. I start another instance of this application on a third computer and add it to the existing communicator. All…
stokastik
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OpenMPI 1.4.3 mpirun hostfile error

I am trying to run a simple MPI program on 4 nodes. I am using OpenMPI 1.4.3 running on Centos 5.5. When I submit the MPIRUN Command with the hostfile/machinefile, I get no output, receive a blank screen. Hence, I have to kill the job. . I use the…
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Configure MPI hostsfile to use multiple user identities

I want to run a program with mpirun on different sets of machines (All linux machines with Open Mpi 1.5). Right now I have machines where I can log on with username A, and another set of machines where I use the username B. All machines are…
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Possible buffer size limit in mpi4py Reduce()

The Setup I'm using mpi4py to element-wise reduce a numpy array across multiple processes. The idea is that the numpy arrays get summed element-wise, so that if I have two processes, and each has arrays: Rank 0: [1, 1, 1] Rank 1: [2, 3, 4] after…
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ORTE_ERROR_LOG: Data unpack would read past end of buffer in file grpcomm_direct.c

Open MPI Version: v4.0.0 Output of ompi_info | head on two machine mpiuser@s2:~$ ssh s1 ompi_info | head Package: Open MPI mpiuser@s1 Distribution Open MPI: 4.0.0 Open MPI repo revision: v4.0.0 Open MPI release…
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MPI A process or daemon was unable to complete a TCP connection

Open MPI: 4.0.1a HostFile: 34bb0519eAAA a2935f150BBB I am in machine 34bb0519eAAA. And I could use ssh a2935f150BBB to connect a2935f150BBB successfully. And also ssh 34bb0519eAAA In machine a2935f150BBB to connect 34bb0519eAAA successfully…
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Fail fast with MPI4PY

I'd like the following behavior when running an MPI script with mpi4py: when any process throws an exception, mpirun (and its spawned processes) should immediately exit with non-zero error codes. But instead, I find that execution continues even if…
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OpenMP or MPI or OpenMPI for a distributed memory cluster?

I want to parallelize a C serial code in a 100 node distributed memory cluster. The cluster consists of 25 blades with 4 cores each by infiniband. Before I just used PBS to spread several serial runs of the program between the different nodes. Now I…
Open the way
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Can't install mpi4py with OpenMPI: Cannot compile MPI programs

it's my first post here so apologies if my style is wrong! I've been trying to install mpi4py (as SU2 requires it for parallel processing) on Ubuntu 16.04 using python 3.6. I downloaded mpi4py and tried to build from source as I would like to use…
Tim Jim
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Open MPI/MPICH - What happens if a node terminates?

I would like to know what happens if a node of a OpenMPI/MPICH2 cluster terminates? Is there some mechanism that is tolerant for this case and continues the execution? Thanks for your answers Heinrich
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What is easier to learn and debug OpenMP or MPI?

I have a number crunching C/C++ application. It is basically a main loop for different data sets. We got access to a 100 node cluster with openmp and mpi available. I would like to speedup the application but I am an absolut newbie for both mpi and…
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Error because file libmpi.so.1 missing

I'm using Omnet++ and Veins for simulations and it was working fine until I upgraded from Ubuntu 15 to 16.04 LTS last night. Now, I get the following error when trying to run a simulation: error while loading shared libraries: libmpi.so.1: cannot…
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How to check which MCA parameters are used in OpenMPI?

In the OpenMPI codebase, each module has multiple variants. When calling mpirun, you can select the modules from the Modular Component Architecture (MCA) that you would like to use. The options include... collective algorithms (coll): basic, tuned,…
solvingPuzzles
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what is the error "failed to write core dump"?

I'm working with java OpenMPI on a server (64GB memory) to sort a big integer array (the length is 1 billion). But when I increase the length of the array, I get this error: A fatal error has been detected by the Java Runtime…
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