All Questions
Tagged with parallel-processing c
1,598 questions
1
vote
0
answers
69
views
loop parallelization with omp
Good morning, I was trying to parallelize a loop with OMP in a program I created for a flood simulator with the goal of achieving a performance boost. The loop I want to parallelize is as follows:
#...
- 11
1
vote
2
answers
168
views
Is it possible to read a file in parallel by extending this function?
I developed this function in C to read a file consisting of one word per line, like a standard wordlist.
The function has already been optimized to a reasonable extent, but I would like to know if ...
- 101
1
vote
0
answers
51
views
Speedup ratio and parallel efficiency of implemented simple parallel matrix multiplication
The following is my source code for parallel calculation matrix multiplication, which tests the parallel efficiency obtained by the number of 1, 2, 4, 8, 16, and 32 threads, respectively.
My Operating ...
- 25
0
votes
1
answer
63
views
How to merge private arrays into a shared one in OMP - C?
I am trying to parallelize a program for finding local maxima using reduction. However, I am encountering a problem during the merging process: the merged array ends up containing exactly two fewer ...
- 3
1
vote
0
answers
35
views
MPI_Bcast not Bcasting
I am running an MPI application on 32 processes.
The stdout of the rank 0 process tgets sent to a separate file for startup error logging, we will call this file STARTUP_ERROR while the stdout of all ...
- 121
1
vote
0
answers
130
views
How to properly execute in parallel several fscanf?
I'm trying to do parallel execution of several fscanf to read file faster
I have 10 nums in a file
10-nums.txt
478
205
256
175
196
52
594
333
72
777
and have a simple code
main.c
#include <stdio.h&...
- 2,027
1
vote
0
answers
104
views
Why does MPI_Sendrecv scale so much better than a separated MPI_Ssend/MPI_Recv call in my parallel C code?
I have written some very basic MPI code in C for image processing which iterates over N iterations and, in every iteration, completes a halo swap between processes using an MPI send/receive routine. I ...
- 11
0
votes
3
answers
114
views
How to combine OMP section and for
Basically I have a parallel loop that has a couple inherently serial variables that I pre-calculate. However I want to be able to set off a given iteration of the for loop once it's serial variables ...
2
votes
1
answer
66
views
Parallelize operations on arrays and merge results into one array using OpenMP
I am trying to speed up a function that, given a complex-valued array arr with n entries, calculates the sum of m operations on that array using BLAS routines. Finally, it replaces the values of arr.
...
- 33
0
votes
1
answer
79
views
Improving MPI performance
Hello I have this problem, I have an MPI program in c that works perfectly fine, but the thing is, I believe it could be improved since the MPI_Allgather() function makes every node wait for the ...
4
votes
1
answer
120
views
How to calculate the length of cycles in a graph using parallel algorithms in C?
I am getting desprite, because I can't solve this problem. I hope this is the right place to ask for help in this context.
The Problem is, that I have a graph that is the union of disjoint directed ...
- 41
0
votes
0
answers
23
views
MPI works with 4 processor but fails with more, problem with decomposition? Send/Recv? 2d Heat diffusion
I have to simulate 2D plate heat diffusion. Everything works fine with 4 tasks, but it doesn't when using N*4 tasks. I suspect the problem is in the logic of communications between the upper and lower ...
0
votes
0
answers
27
views
Asking for buffer size dimension in MPI_Bsend usage
I'm currently studying MPI library for C and I can't understand which is the best way to determine the buffer size for my MPI_Bsend to work properly. The slides which I am studying from say that the ...
0
votes
1
answer
83
views
OpenMP parallel for is substantially slower than sequential
I am running a simulation of random events happening in accordance with a given set of probabilities, until n events are hit, and repeating for as many iterations as desired. When I run this ...
- 59
2
votes
1
answer
107
views
Track progress in a thread with OpenMP
Im trying to create a programm that displays value from different thread every second, as an attempt at progress tracking functionality, but unfortunatly i cant seam to correctly parallelise this case ...
- 39