mpi

问题 Consider the configuration to be First: Not buffered, blocking(synchronous) As I understand MPI is an API, so when we do the mpi_send blocking function call, does the sender function/program get blocked? OR Does the MPI API function mpi_send get blocked, so that the program can continue its work till message is sent? Second: Similar confusion, does the mpi_recv get blocked or the function from where it was called gets blocked? Reason for such a stupid question: It's parallel processing so why

问题 Consider the configuration to be First: Not buffered, blocking(synchronous) As I understand MPI is an API, so when we do the mpi_send blocking function call, does the sender function/program get blocked? OR Does the MPI API function mpi_send get blocked, so that the program can continue its work till message is sent? Second: Similar confusion, does the mpi_recv get blocked or the function from where it was called gets blocked? Reason for such a stupid question: It's parallel processing so why

问题 I am currently using the MPI C library, but coding c++, I know that MPI_Barrier(MPI_COMM_WORLD) function blocks the caller until all processes in the communicator have called it , as in the documentation. Here is my code, running on 4 processes. int WORLD_SIZE = 0; int WORLD_RANK = 0; { MPI_Init(&argc, &argv); MPI_Comm_size(MPI_COMM_WORLD, &WORLD_SIZE); MPI_Comm_rank(MPI_COMM_WORLD, &WORLD_RANK); MPI_Barrier(MPI_COMM_WORLD); } // everything works up till here // WORLD_SIZE is 4, WORLD_RANK is

问题 I want to find the first k results over all nodes using MPI. For that I wanted to use MPI_Reduce with an own function. However my code does not work because the len parameter of the function is not the same as the count parameter given to MPI_Reduce. I found here that implementations may do this to pipeline the computation. My code is similar to this one: inline void MPI_user_select_top_k(int *invec, acctbal_pair *inoutvec, int *len, MPI_Datatype *dtpr) { std::vector<acctbal_pair> temp; for

问题 I am very frustrated after a whole week of trying everything imaginable and unimaginable, it seems that their SDK ( https://www.microsoft.com/en-us/download/details.aspx?id=57467 ) is missing something: C:\Anaconda3\PCbuild\amd64 /LIBPATH:build\temp.win-amd64-3.7 "/LIBPATH:C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\LIB\amd64" "/LIBPATH:C:\Program Files (x86)\Windows Kits\10\lib\10.0.17763 .0\ucrt\x64" "/LIBPATH:C:\Program Files (x86)\Windows Kits\10\lib\10.0.17763.0\um\x64" "

问题 Can someone tell me why this minimal working example (MWE) complains of TypeError: expected a writeable buffer object ? MWE: #!/usr/bin/env python from mpi4py import MPI # MPI Initialization rank = MPI.COMM_WORLD.Get_rank() comm = MPI.COMM_WORLD if __name__ == '__main__': a = True if rank == 0: a = False comm.Send ( [ a, MPI.BOOL ], 1, 111 ) if rank == 1: comm.Recv ([ a, MPI.BOOL], 0, 111 ) Error: Traceback (most recent call last): File "test.py", line 14, in <module> comm.Recv ([ a, MPI.BOOL

问题 I got access to an HPC cluster with a MPI partition. My problem is that -no matter what I try- my code (which works fine on my PC) doesn't run on the HPC cluster. The code looks like this: library(tm) library(qdap) library(snow) library(doSNOW) library(foreach) > cl<- makeCluster(30, type="MPI") > registerDoSNOW(cl) > np<-getDoParWorkers() > np > Base = "./Files1a/" > files = list.files(path=Base,pattern="\\.txt"); > > for(i in 1:length(files)){ ...some definitions and variable generation...

问题 The cmake file below is the source of problem because I can compile the code with mpic++ directly and without using cmake. Why the cmake file below doesn't work? Current cmake file: cmake_minimum_required(VERSION 2.8) project(boost_mpi_cmake) set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11") add_executable(test test.cpp) find_package(Boost REQUIRED mpi system) include_directories(${Boost_INCLUDE_DIRS}) target_link_libraries(test ${Boost_LIBRARIES}) find_package(MPI REQUIRED) include

问题 Recently I try to make use of the department cluster to do parallel computing in R . The cluster system is manged by SGE . OpenMPI has been installed and passed the installation test. I submit my query to the cluster via qsub command. In the script, I specify the number of node I want to use via the following command. #PBS -l nodes=2:ppn=24 (two nodes with 24 threads each) Then, mpirun -np 1 R --slave -f test.R I have checked $PBS_NODEFILE afterwards. Two nodes are allocated as I wish. I

问题 In my MPI program, I want to send and receive information to adjacent processes. But if a process ends and doesn't send anything, its neighbors will wait forever. How can I resolve this issue? Here is what I am trying to do: if (rank == 0) { // don't do anything until all slaves are done } else { while (condition) { // send info to rank-1 and rank+1 // if can receive info from rank-1, receive it, store received info locally // if cannot receive info from rank-1, use locally stored info // do