openmp

Hi just wondering if this is the right way to go going about having a regular for loop but with two reductions , is this the right approach below? Would this work with more then two reductions as well. Is there a better way to do this? also is there any chance to integrate this with an MPI_ALLREDUCE command? heres the psuedo code #pragma omp parallel for \ default(shared) private(i) \ //todo first reduction(+:sum) //todo second reduction(+:result) for loop i < n; i ++; { y = fun(x,z,i) sum += fun2(y,x) result += fun3(y,z) } You can do reduction by specifying more than one variable separated by

I have the following C/C++ code using OpenMP: int nProcessors=omp_get_max_threads(); if(argv[4]!=NULL){ printf("argv[4]: %s\n",argv[4]); nProcessors=atoi(argv[4]); printf("nProcessors: %d\n",nProcessors); } omp_set_num_threads(nProcessors); printf("omp_get_num_threads(): %d\n",omp_get_num_threads()); exit(0); As you can see, I'm trying to set the number of processors to use based on an argument passed on the command line. However, I'm getting the following output: argv[4]: 2 //OK nProcessors: 2 //OK omp_get_num_threads(): 1 //WTF?! Why isn't omp_get_num_threads() returning 2?!!! As has been

In my code I have loop in which I construct and over determined linear system and try to solve it: #pragma omp parallel for for (int i = 0; i < n[0]+1; i++) { for (int j = 0; j < n[1]+1; j++) { for (int k = 0; k < n[2]+1; k++) { arma::mat A(max_points, 2); arma::mat y(max_points, 1); // initialize A and y arma::vec solution = solve(A,y); } } } Sometimes, quite randomly the program hangs or the results in the solution vector are NaN. And if I put do this: arma::vec solution; #pragma omp critical { solution = solve(weights*A,weights*y); } then these problem don't seem to happen anymore. When it

I have a CPU consuming function do_long that I need to run on two different datasets. do_long(data1); do_long(data2); do_long() { #pragma omp for for(...) { // do proccessing } } I have N threads available (depends on machine). How to tell OpenMP that I want that both do_long functions are run in parallel, and N/2 threads should perform the loop in first do_long and another N/2 should process second do_long ? One approach is to do it using nested parallelism: void do_long(int threads) { #pragma omp parallel for num_threads(threads) for(...) { // do proccessing } } int main(){ omp_set_nested(1)

This question already has answers here : Undefined reference to `omp_get_max_threads_' (3 answers) I am trying to run simple OpenMP program in CLion IDE . When I run it I get an ERROR: CMakeFiles\openmp_test_clion.dir/objects.a(main.cpp.obj): In function `main': D:/.../openmp_test_clion/main.cpp:9: undefined reference to 'omp_get_thread_num' collect2.exe: error: ld returned 1 exit status Here is my code: #include <stdio.h> #include <omp.h> int main() { int id; #pragma omp parallel private(id) { id = omp_get_thread_num(); printf("%d: Hello World!\n", id); } return 0; } Here is my CMakeLists.txt

I'm writing a program for matrix multiplication with OpenMP, that, for cache convenience, implements the multiplication A x B(transpose) rows X rows instead of the classic A x B rows x columns, for better cache efficiency. Doing this I faced an interesting fact that for me is illogic: if in this code i parallelize the extern loop the program is slower than if I put the OpenMP directives in the most inner loop, in my computer the times are 10.9 vs 8.1 seconds. //A and B are double* allocated with malloc, Nu is the lenght of the matrixes //which are square //#pragma omp parallel for for (i=0; i

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: How can I get OpenMP to run on Mac OSX 10.11, so that I can execute scripts via terminal ? I have installed OpenMP: brew install clang-omp . When I run, for example: gcc -fopenmp -o Parallel.b Parallel.c the following expression returns: fatal error: 'omp.h' file not found I have also tried: brew install gcc --without-multilib but unfortunately this eventually returned the following (after first installing some dependencies): The requested URL returned error : 404 Not Found Error : Failed to download resource "mpfr--patch" Any