mpi Questions
2
Solved
I am trying to send std:vector using MPI send and recv functions but I have reached no where.
I get errors like
Fatal error in MPI_Recv: Invalid buffer pointer, error stack:
MPI_Recv(186): MPI_Re...
Irreligion asked 16/3, 2015 at 2:27
3
I have a Fortran program where I specify the kind of the numeric data types in an attempt to retain a minimum level of precision, regardless of what compiler is used to build the program. For examp...
2
Solved
I'm new to Homebrew (I usually use Macports, but I'm trying out Homebrew on a 2nd computer), and I wish to install the openmpi (or mpich2) package. Steps are as follows (carried out on Mac OS X Yos...
1
Solved
I'm currently writing a simulation using boost::mpi on top of openMPI and everything works great. However once I scale up the system and therefore have to send larger std::vectors I get errors.
I'...
3
I have a project and I have to improve its performance. I have a big Mysql database constructed from a huge CSV file (100 millions rows). Insert time is not a problem, but response time of a reques...
Raffish asked 22/5, 2011 at 19:47
1
Solved
I have the following code:
//Start MPI...
MPI_Init(&argc, &argv);
int size = atoi(argv[1]);
int delta = 10;
int rnk;
int p;
int root = 0;
MPI_Status mystatus;
MPI_Comm_rank(MPI_COMM_WOR...
Glabrate asked 2/3, 2015 at 14:7
2
Solved
I'm running Ubuntu 11.04 64-bit. I have installed OpenMPI. I'm trying to build the following code, which is a snippet from a test problem from the book "Using MPI" by Gropp/Lusk/Skjellum:
#include...
Polytypic asked 7/12, 2012 at 2:42
1
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Does MPI standard provide a preprocessor macro, so my C/C++ code could branch if it is compiled by MPI-enabled compiler? Something like _OPENMP macro for OpenMP.
1
Solved
Looking at the following extract from the openmpi manual
--map-by <foo>
Map to the specified object, defaults to socket. Supported options
include slot, hwthread, core, L1cache, L2cache, L...
2
Solved
I've got an MPI program consisting of one master process that hands off commands to a bunch of slave processes. Upon receiving a command, a slave just calls system() to do it. While the slaves are ...
1
Solved
What is the difference between these two compilers, mpif90 and mpifort? Both seems to be for Fortran 90 code. Both got installed when I installed openMPI on Linux. Are the usage (compiler options) ...
2
I am trying to install MPI for Windows 8, so when I searched net I got steps for installing it on XP/7 but not for windows 8. The link is: http://swash.sourceforge.net/online_doc/swashimp/node9.htm...
Admittedly asked 16/1, 2014 at 5:6
0
There is a problem with MPI - program works when there is an internet connection on my PC, but doesn't work without it.
I got this error:
It looks like orte_init failed for some reason; your p...
1
I got slightly mixed up regarding the concept of synchronous - asynchronous in the context of blocking & non blocking operations (in OpenMPI) from here:
link 1
: MPI_Isend is not necessarily ...
Haskins asked 12/11, 2014 at 7:18
1
Solved
I am trying to understand the MPI_Reduce_scatter function but it seems that my deductions are always wrong :(
The documentation says (link):
MPI_Reduce_scatter first does an element-wise reduction...
Hairstyle asked 10/9, 2014 at 21:25
1
Solved
I have a python script that I've written using the multiprocessing module, for faster execution. The calculation is embarrassingly parallel, so the efficiency scales with the number of processors. ...
Flitch asked 10/9, 2014 at 18:13
4
With the syntax for MPI::Isend as
MPI::Request MPI::Comm::Isend(const void *buf, int count,
const MPI::Datatype& datatype,
int dest, int tag) const;
is the amount of data sent limited by...
2
Solved
I'm looking to create Rust implementations of some small bioinformatics programs for my research. One of my main considerations is performance, and while I know that I could schedule the Rust progr...
Beak asked 8/4, 2014 at 22:31
6
Correct me if I'm wrong, but my understanding is that Hadoop does not use MPI for communication between different nodes.
What are the technical reasons for this?
I could hazard a few guesses, but...
Nariko asked 4/1, 2011 at 4:34
1
Solved
I am launched an MPI program with MVAPICH2 and got this error:
Fatal error in PMPI_Gather:
Invalid buffer pointer, error stack:
PMPI_Gather(923): MPI_Gather() failed
PMPI_Gather(857): Buffers must...
5
Solved
As far as I understand, MPI gives me much more control over how exactly different nodes in the cluster will communicate.
In MapReduce/Hadoop, each node does some computation, exchanges data with o...
Married asked 7/10, 2009 at 9:22
1
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I'm learning about BCASTing data types in Fortran and have a code which takes two values from the terminal and displays them on each process. For the combination value1/value2 of type integer/integ...
2
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I would like to ask a question about rand() in the context of (Open)MPI. We were given an implementation task in our parallel programming course - create an MPI application in which all participant...
1
Solved
Just looking over some notes prior to an interview and am struggling to understand how Odd-Even sort works in parallel architectures.
int MPI_OddEven_Sort(int n, double *a, int root, MPI_Comm comm...
2
Solved
In order to compile MPI code in gfortran I have to use the syntax
include mpif.h
in my code instead of
use mpi
Several websites indicate that this syntax is for Fortran 77 however, I am using...
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