openmp

问题 I am new to OpenMP, and my professor gives us a project to do. There are only three files in the folder: a C++ source code a0.cpp, a header a0.h, and a Makefile. When I want to run the code in my terminal, it says: clang: error: unsupported option '-fopenmp' clang: error: unsupported option '-fopenmp' make: *** [a0] Error 1 I am using a Macbook, and I do not know how to fix this. Can you help me? Thanks. 回答1: After installing libomp with homebrew using: brew install libomp I was able to

问题 I just wonder how to convert the following openMP program to a MPI program #include <omp.h> #define CHUNKSIZE 100 #define N 1000 int main (int argc, char *argv[]) { int i, chunk; float a[N], b[N], c[N]; /* Some initializations */ for (i=0; i < N; i++) a[i] = b[i] = i * 1.0; chunk = CHUNKSIZE; #pragma omp parallel shared(a,b,c,chunk) private(i) { #pragma omp for schedule(dynamic,chunk) nowait for (i=0; i < N; i++) c[i] = a[i] + b[i]; } /* end of parallel section */ return 0; } I have a similar

问题 Hello dear Communauts, I'm am creating a terminal animated status report for a parallel software I'm developing. I'm using NCurses. I'm having an issue related to the restoring of the standard behavior of the terminal. After running my software the terminal keeps having just 24 lines, no matter if I call endwin() or I don't. Here the simplified code: int size=10; initscr(); refresh(); while(KeepAlive){ int j=1; mvprintw(j,0,/*Blah blah header*/)); for(int i=0;i<size;i++){ j++; mvprintw(j,0,/

问题 I am writing a fortran code using task-based paradigm. I use my DAG to express the dependencies. Using OpenMP 4.5, I can use the clause depend which takes as input a dependence-type and a list of dependencies. This mechanism works well when you know explicitly the number of dependencies. However, in my case, I would create tasks that are expected to have a list of dependencies which varies from 1 to n elements. Reading the documentation OpenMP-4.5_doc, I have not found any useful mechanism

问题 I'm using OpenMP for this and I'm not confident of my answer as well. Really need your help in this. I've been wondering which method (serial or parallel) is faster in run speed in this. My #pragma commands (set into comments) are shown below. Triangle Triangle::t_ID_lookup(Triangle a[], int ID, int n) { Triangle res; int i; //#pragma omp for schedule(static) ordered for(i=0; i<n; i++) { if(ID==a[i].t_ID) { //#pragma omp ordered return (res=a[i]); // <-changed into "res = a[i]" instead of

问题 I would like to parallelise a linear operation (fitting a complicated mathematical function to some dataset) with multiple processors. Assume I have 8 cores in my machine, and I want to fit 1000 datasets. What I expect is some system that takes the 1000 datasets as a queue, and sends them to the 8 cores for processing, so it starts by taking the first 8 from the 1000 as FIFO. The fitting times of each dataset is in general different than the other, so some of the 8 datasets being fitted could

问题 I'm having a Segmentation Fault when accessing an array inside a for loop. What I'm trying to do is to generate all subsequences of a DNA string. It was happening when I created the array inside the for. After reading for a while, I found out that the openmp limits the stack size, so it would be safer to use the heap instead. So I change the code to use malloc, but the problem persists. This is the full code: #include <limits.h> #include <stdio.h> #include <stdlib.h> #include <math.h>

问题 I am currently trying to improve parallel performance on my Code and I am still new to OpenMP. I have to iterate over a large container, in each iteration reading from multiple entries and writing a result to a single entry. Below is a very minmal Code example of what I am trying to do. data is a pointer to an array, where a lot of datapoints are stored. Before the parallel region I create an Array newData , so can use data as read-only and newData as write-only, afterwards I throw the old

问题 What i am trying to do: I am working on C/c++ codes to build a product for all platforms(I OS/Android/Windows(mobile/desktop)/Mac/Linux ) What have i done so far: Yes there are many online links talking about OpenMp's Compatibility with different processors and OS's, but its hard to make a logical conclusion from them because many are older article or posts especially wrt to mobile targets. Ref: Link As per my analysis, yes, openMp can work with all desktop OS's (Windows/Mac/Linux) and almost

问题 I'm writing a matrix multiplication subroutine in Fortran. I'm using the Intel Fortran compiler. I've written a simple static scheduled parallel do-loop. Unfortunately, it's running on only one thread. Here's the code: SUBROUTINE MATMULT(A,B,C,L,M,N) REAL*8 A,B,C INTEGER NCORES, CHUNK, TID DIMENSION A(L,N),B(L,M),C(M,N) PARAMETER (NCORES=8) CHUNK=(L/(NCORES+1))+1 TID=0 !$OMP PARALLELDO SHARED(A,B,C,L,M,N,CHUNK) PRIVATE(I,J,K,TID) !$OMP+DEFAULT(NONE) SCHEDULE(STATIC,CHUNK) DO I=1,L TID = OMP