openmp

Running multiprocess applications from MATLAB

由 最后都变了- 提交于 2020-01-11 09:09:31
问题 I've written a multitprocess application in VC++ and tried to execute it with command line arguments with the system command from MATLAB. It runs, but only on one core --- any suggestions? Update :In fact, it doesn't even see the second core. I used OpenMP and used omp_get_max_threads() and omp_get_thread_num() to check and omp_get_max_threads() seems to be 1 when I execute the application from MATLAB but it's 2 (as is expected) if I run it from the command window. Question :My task manager

OpenMP parallel thread

由 一个人想着一个人 提交于 2020-01-11 07:17:13
问题 I need to parallelize this loop, I though that to use was a good idea, but I never studied them before. #pragma omp parallel for for(std::set<size_t>::const_iterator it=mesh->NEList[vid].begin(); it!=mesh->NEList[vid].end(); ++it){ worst_q = std::min(worst_q, mesh->element_quality(*it)); } In this case the loop is not parallelized because it uses iterator and the compiler cannot understand how to slit it. Can You help me? 回答1: OpenMP requires that the controlling predicate in parallel for

Thread-safety of boost RNG

由 瘦欲@ 提交于 2020-01-11 05:58:07
问题 I have a loop which should be nicely parallelized by insering one openmp pragma: boost::normal_distribution<double> ddist(0, pow(retention, i - 1)); boost::variate_generator<gen &, BOOST_TYPEOF(ddist)> dgen(rng, ddist); // Diamond const std::uint_fast32_t dno = 1 << i - 1; // #pragma omp parallel for for (std::uint_fast32_t x = 0; x < dno; x++) for (std::uint_fast32_t y = 0; y < dno; y++) { const std::uint_fast32_t diff = size/dno; const std::uint_fast32_t x1 = x*diff, x2 = (x + 1)*diff;

User Defined Reduction on vector of varying size

由 丶灬走出姿态 提交于 2020-01-11 02:49:12
问题 I'm trying to define my own reduction for vectors of complex<float>, following this answer to the question Reducing on array in OpenMP. But the size of my vectors aren't fixed at compile time, so I'm not sure how to define the initializer for the vector in the declare reduction pragma. That is, I can't just have initializer( omp_priv=TComplexVector(10,0) ) But the initializer is needed for vectors. How can I pass the initializer clause the size of the vector I need at run time? What I have so

openmp(1)----计时

由 放肆的年华 提交于 2020-01-10 11:06:53
时间是用来评价一个算法或代码的重要指标。 clock_t 为时钟周期数，在并行程序中这种方式不能测量时间。 #include <time.h> clock_t start,finish; start = clock(); finish = clock(); std::cout<<"完成需要 "<<finish - start<<"个时钟周期"<<std::endl; std::cout<<"消耗时间为:"<<(finish - start)/CLOCKS_PER_SEC*1000<<"ms\n"<<std::endl; // CLOCKS_PER_SEC 每秒德时钟周期数 double omp_get_wtime() 返回绝对时间，单位为s #include<omp.h> double start = omp_get_wtime( ); double end = omp_get_wtime( ); double omp_get_wtick() 返回单个时钟周期的时间，s #include "omp.h" #include <stdio.h> //获得一个时钟周期是多少秒 double wtick = omp_get_wtick( ); printf("wtick = %.16g\n1/wtick = %.16g\n", wtick, 1.0 / wtick); //

When is the reduction needed?

由 余生长醉 提交于 2020-01-09 11:50:00
问题 I've written this code which reads a Matrix and it basically sums the values of the matrix... But my question would be, since I've tried doing the pragma in different ways, I found that the reduction (+:sum) wouldn't be necessary, but, I just don't know why, I might have missed the actual sense of the reduction system in this case. This would be the alternative: #pragma omp parallel for private(i, j) reduction (+:sum) And this would be the code: #include <stdio.h> #include <math.h> #include

Fortran OpenMP with subroutines and functions

由 徘徊边缘 提交于 2020-01-09 10:52:01
问题 Disclaimer: I'm quite certain that this has been answered somewhere, but myself and another person have been searching quite hard to no avail. I've got a code that looks something like this: PROGRAM main !$omp parallel do !$omp private(somestuff) shared(otherstuff) DO i=1,n ... CALL mysubroutine(args) ... a=myfunction(moreargs) ... ENDDO !$omp end parallel do END PROGRAM SUBROUTINE mysubroutine(things) ... END SUBROUTINE FUNCTION myfunction(morethings) ... END FUNCTION I cannot determine

Fortran OpenMP with subroutines and functions

由 [亡魂溺海] 提交于 2020-01-09 10:50:54
问题 Disclaimer: I'm quite certain that this has been answered somewhere, but myself and another person have been searching quite hard to no avail. I've got a code that looks something like this: PROGRAM main !$omp parallel do !$omp private(somestuff) shared(otherstuff) DO i=1,n ... CALL mysubroutine(args) ... a=myfunction(moreargs) ... ENDDO !$omp end parallel do END PROGRAM SUBROUTINE mysubroutine(things) ... END SUBROUTINE FUNCTION myfunction(morethings) ... END FUNCTION I cannot determine

brew install clang-omp not working

由 你说的曾经没有我的故事 提交于 2020-01-09 06:30:58
问题 I need to compile a C++ code with OpenMP on my Mac. Unfortunately the default version of clang installed on the Mac (703.0.31) does not support OpenMP. Therefore, I am trying to install the clang-omp package with brew (e.g., following this guide). The issue is that brew cannot find neither the libiomp, nor the clang-omp package: $ brew install clang-omp Error: No available formula with the name "clang-omp" ==> Searching for similarly named formulae... Error: No similarly named formulae found.

brew install clang-omp not working

由 爱⌒轻易说出口 提交于 2020-01-09 06:29:07
问题 I need to compile a C++ code with OpenMP on my Mac. Unfortunately the default version of clang installed on the Mac (703.0.31) does not support OpenMP. Therefore, I am trying to install the clang-omp package with brew (e.g., following this guide). The issue is that brew cannot find neither the libiomp, nor the clang-omp package: $ brew install clang-omp Error: No available formula with the name "clang-omp" ==> Searching for similarly named formulae... Error: No similarly named formulae found.
订阅 openmp