OMP_NUM_THREADS=4 如果不定义OMP_NUM_THREADS,默认会等于CPU数量,在8核心的机器上,会打印出8行"Hello World". omp_set_num_threads(8); 设置了子线程数为8,即是可以有8个子线程并行运行。 #pragma omp parallel private(nthreads,tid) 为编译制导语句,每个线程都自己的nthreads和tid两个私有变量,线程对私有...
Using OpenMP, you have basically 3 different ways of specifying the number of threads to use in a parallel region: The most commonly used one is the environment variable OMP_NUM_THREADS which needs to be set in the code's environment prior to running it for being effecti...
%setenv OMP_NESTED TRUE%setenv SUNW_MP_MAX_POOL_THREADS 5%a.outLevel 1: number of threads in the team - 2 Level 2: number of threads in the team - 2 Level 2: number of threads in the team - 2 Level 3: number of threads in the team - 2 Level 3: number of threads in the ...
omp_set_num_threads(NUM_THREADS);#pragmaomp parallel default(none) private(i) shared(nSum, nThreads, nStart, nEnd){#pragmaomp masternThreads = omp_get_num_threads();#pragmaomp forfor(i=nStart; i<=nEnd; ++i) {#pragmaomp atomicnSum += i; } }if(nThreads == NUM_THREADS) { printf...
omp_set_num_threads(NUM_THREADS);#pragmaomp parallel default(none) private(i) shared(nSum, nThreads, nStart, nEnd){#pragmaomp masternThreads = omp_get_num_threads();#pragmaomp forfor(i=nStart; i<=nEnd; ++i) {#pragmaomp atomicnSum += i; } }if(nThreads == NUM_THREADS) { printf...
2. omp_get_num_threads/omp_set_num_threads 设置/获取线程数量,此set函数是上面确定遇到parallel指令后创建team的线程的决定方式之一,用于覆盖OMP_NUM_THREADS环境变量的设置。 说明:尽管从函数名上看,它们是一对set/get函数,但是要区分它们的含义,set之后马上get,其值不一定等于set的结果,而且大部分情况都是不...
//file name: test_openmp.c#include<stdio.h>#include<omp.h>intmain(int argc,char**argv){int num_thread=4;omp_set_num_threads(num_thread);#pragma omp parallel{int id=omp_get_thread_num();printf("hello from thread%d\n",id);}return0;} ...
Returns the number of threads in the parallel region. C++Copy intomp_get_num_threads( ); Remarks For more information, see3.1.2 omp_get_num_threads function. Example C++Copy // omp_get_num_threads.cpp// compile with: /openmp#include<stdio.h>#include<omp.h>intmain(){ omp_set_num_thr...
Library (oneMKL) does not set the default number of OpenMP threads to one, but depends on the OpenMP libraries used with the compiler to set the default number. For the threading layer based on the Intel compiler (libmkl_intel_thread.a), this value is the number of CPUs according to ...
number of threads indicated by the OMP_NUM_THREADS environment variable* - 2nd step: using the number of threads overriden by omp_set_num_threads**/intmain(intargc,char*argv[]){#pragma omp parallel{#pragma omp single{printf("From the environment variable, parallel regions contain %d threads....