DLL load failed: The specified module could not be found when doing "from mpi4py import MPI"

I am trying to use Mpi4py 1.3 with python 2.7 on Windows 7 64bits. I downloaded the installable version from here which includes OpenMPI 1.6.3 so in the installed directory...

mpi4py returning rank differences

I want to launch parallel processes from a python script (and, for testing, interactively, but not from ipython), across two different versions of python, and have started out with mpi4py. The two...

How do I remove the memory limit on openmpi processes?

I'm running a process with mpirun and 2 cores and it gets killed at the point when I'm mixing values between the two processes. Both processes use about 15% of the machines memory and even though...

How to identify conda package dependents?

For a given conda package, how to I list the packages that depend on it? I recently installed anaconda on a university cluster that already had a version of MPI (openmpi). The mpich2 package and...

Error when installing mpi4py

I'm trying to install mpi4py using pip install mpi4py, but I'm getting the following error: error: Cannot find 'mpi.h' header. Check your configuration!!! Earlier in the same error report I...

mpiexec and python mpi4py gives rank 0 and size 1

I have a problem with running a python Hello World mpi4py code on a virtual machine. The hello.py code is: #!/usr/bin/python #hello.py from mpi4py import MPI comm = MPI.COMM_WORLD size =...

Mpi4Py - sending numpy subarray (non-contiguous memory) without copy

I am rewriting communication bottleneck. I need to send sub-arrays of 3d numpy arrays. But passing the sub-array directly to MPI.Send() fails with: ValueError: ndarray is not contiguous Creating...

Replacing multiprocessing pool.map with mpi4py

I'm a beginner in using MPI, and I'm still going through the documentation. However, there's very little to work on when it comes to mpi4py. I have written a code that currently uses the...

MPI4py error "tmi fabric is not available and fallback fabric is not enabled"

I am running a code that spawns mpi processes with a system call within python. The code runs fine in some cases, but when I increase the number of workers spawned on a node beyond a certain point...

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...

Processes are spawned before the MPIPoolExecutor initialization. In addition can I use a HPC with the ProccesPoolExecutor?

I am using the mpi4py library for parallel programming. But it seems that processes are spawned before I creat my MPIPoolExecutor, since I got 4 times the same warning that it lies before the...

Packaging with manylinux + auditwheel pip wheels vs. Conda

Description So I am looking to package a fairly complex python application that requires scientific libraries. This question is somewhat similar to the stackoverflow pip vs conda discussion but it...

parallel write to different groups with h5py

I'm trying to use parallel h5py to create an independent group for each process and fill each group with some data.. what happens is that only one group gets created and filled with data. This is...

Error when using terminal to run mpi4py file

I want to run a mpi4py test file in terminal but it failed. The operating system is mac and I am using anaconda2 with a python3. I installed mpi4py through anaconda environment. It works will on...

Determine if Python program is running in parallel

Is there a way to find out whether a Python program is running in parallel through mpirun or mphexec. I thought I could get this information by getting sys.argv but it's not there. Is there any...

PyTorch "NCCL error: unhandled system error" during backprop

I am trying to do distributed training with PyTorch and encountered a problem. This runtime error occurs during backprop (first batch, first epoch). File...

Understanding Put/Get in mpi4py

I'm learning how to use one-sided communication in mpi4py. To test my understanding, I came up with this contrived example: import mpi4py.MPI as mpi import numpy as np import time def main(): ...

[Python]: mpi4py parallel numpy dot product

So I was trying to parallel the numpy's dot product using mpi4py on a cluster. The basic idea is to split the first matrix to smaller ones, multiply the smaller ones with the second matrix and...

Kill an MPI process in all machines

Suppose that I run an MPI program involving 25 processes on 25 different machines. The program is initiated at one of them called the "master" with a command like mpirun -n 25 --hostfile...

How to fix a problem that "apt-get install" doesn't work because of python issue

I'm using Ubuntu 16.04.I'd like to install a ROS related package with "apt-get install", but it doesn't work. Terminal said like following. $ sudo apt-get install ros-kinetic-libuvc Reading...

How nodes communicate in OpenMPI

I am able to run OpenMPI job in multiple nodes under ssh. Everything looks good but I find that I do not know much about what is really happening. So, how nodes communicate in OpenMPI? It's in...

Python code takes longer to run with MPI (SLURM) than as a single process

I have some python code which takes approximately 12 hours to run on my laptop (MacOS 16GB 2133 MHz LPDDR3). The code is looping over a few thousand iterations and doing some intensive processing...

Python: Running sequential and parallel tests at once

I recently extended the scope of one of the functions of my python module so that it can be executed sequentially or in parallel (with mpi4py). def foo(param, use_mpi=False): pass When I run...

Stable Baselines: DQN Not performing properly?

I have problem in using DQN for a diagonal line and sin wave as price fluctuation. When the price goes up, there will be a reward and it is colored as green in the chart. When the price goes down...

Error in slurm for using mpirun conda environment

I am getting errors whenever I use mpirun inside batch script in an active conda environment (but this error does not happen if I don't use a batch script, or if I am not in a conda...

How to apply chain rule to multiple tf.GradientTape?

I'm studying pipeline model parallelism with TensorFlow 2 and MPI. But I can't figure out how to apply the chain rule when using multiple tf.GradientTape across multiple processes. Here is the...

ValueError in MPI scatter method while using 2D list in Python-mpi4py

I have a csv file that I read it into a 2D list and I want to use scatter method in MPI (mpi4py) to send different chunk of this list into different processing elements to process them as...

Sudden Tensorflow / Keras Google Colab dependency problems `AttributeError: module 'tensorflow._api.v1.compat.v2' has no attribute '__internal__'`

I have running a machine learning model (Matterport's Mask R-CNN) in google colab for a couple of weeks. All of a sudden today I am unable to run any of my notebooks due to I think some kind of...

How to train tensorflow.keras models in parallel using gpu? Tensorflow version 2.5.0

I have the following code running a custom model that I have in a different module and takes as input several parameters (learning rate, convolution kernel size, etc) custom_model is a function...

pybind11: send MPI communicator from Python to CPP

I have a C++ class which I intend to call from python's mpi4py interface such that each node spawns the class. On the C++ side, I'm using the Open MPI library (installed via homebrew) and...