犰狳是否解决()线程安全？

在我的代码中，我有一个循环，在这个循环中，我构造并且超过确定的线性系统，并且尝试解决它:

#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);
}
}
}

有时，程序随机挂起或解向量中的结果是 NaN。如果我这样写:

arma::vec solution;
#pragma omp critical
{
solution = solve(weights*A,weights*y);
}

那么这些问题就不会再发生了。

当它挂起时，是因为一些线程正在 OpenMP 屏障处等待:

Thread 2 (Thread 0x7fe4325a5700 (LWP 39839)):
#0  0x00007fe44d3c2084 in gomp_team_barrier_wait_end () from /usr/lib64/gcc-4.9.2/lib64/gcc/x86_64-redhat-linux-gnu/4.9.2/libgomp.so.1
#1  0x00007fe44d3bf8c2 in gomp_thread_start () at ../.././libgomp/team.c:118
#2  0x0000003f64607851 in start_thread () from /lib64/libpthread.so.0
#3  0x0000003f642e890d in clone () from /lib64/libc.so.6

其他的线都卡在犰狳里面:

Thread 1 (Thread 0x7fe44afe2e60 (LWP 39800)):
#0  0x0000003ee541f748 in dscal_ () from /usr/lib64/libblas.so.3
#1  0x00007fe44c0d3666 in dlarfp_ () from /usr/lib64/atlas/liblapack.so.3
#2  0x00007fe44c058736 in dgelq2_ () from /usr/lib64/atlas/liblapack.so.3
#3  0x00007fe44c058ad9 in dgelqf_ () from /usr/lib64/atlas/liblapack.so.3
#4  0x00007fe44c059a32 in dgels_ () from /usr/lib64/atlas/liblapack.so.3
#5  0x00007fe44f09fb3d in bool arma::auxlib::solve_ud<double, arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times> >(arma::Mat<double>&, arma::Mat<double>&, arma::Base<double, arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times> > const&) () at /usr/include/armadillo_bits/lapack_wrapper.hpp:677
#6  0x00007fe44f0a0f87 in arma::Col<double>::Col<arma::Glue<arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times>, arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times>, arma::glue_solve> >(arma::Base<double, arma::Glue<arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times>, arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times>, arma::glue_solve> > const&) ()
at /usr/include/armadillo_bits/glue_solve_meat.hpp:39

正如你从堆栈跟踪中看到的，我的犰狳版本使用了地图集。根据这份文档，地图集似乎是线程安全的: Ftp://lsec.cc.ac.cn/netlib/atlas/faq.html # tsafe

2015年9月11日更新

我终于有时间运行更多的测试，基于弗拉基米尔 F 的建议。

当我用 ATLAS 的 BLAS 编译犰狳时，我仍然能够复制然后挂起和 NaN。当它挂起时，堆栈跟踪中唯一改变的是对 BLAS 的调用:

#0  0x0000003fa8054718 in ATL_dscal_xp1yp0aXbX@plt () from /usr/lib64/atlas/libatlas.so.3
#1  0x0000003fb05e7666 in dlarfp_ () from /usr/lib64/atlas/liblapack.so.3
#2  0x0000003fb0576a61 in dgeqr2_ () from /usr/lib64/atlas/liblapack.so.3
#3  0x0000003fb0576e06 in dgeqrf_ () from /usr/lib64/atlas/liblapack.so.3
#4  0x0000003fb056d7d1 in dgels_ () from /usr/lib64/atlas/liblapack.so.3
#5  0x00007ff8f3de4c34 in void arma::lapack::gels<double>(char*, int*, int*, int*, double*, int*, double*, int*, double*, int*, int*) () at /usr/include/armadillo_bits/lapack_wrapper.hpp:677
#6  0x00007ff8f3de1787 in bool arma::auxlib::solve_od<double, arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times> >(arma::Mat<double>&, arma::Mat<double>&, arma::Base<double, arma::Glue<arma::Mat<double>, arma::Mat<double>, arma::glue_times> > const&) () at /usr/include/armadillo_bits/auxlib_meat.hpp:3434

在没有 ATLAS、只有 netlib BLAS 和 LAPACK 的情况下进行编译，我能够复制 Nan，但不能复制 hang。

在这两种情况下，周围的 solve()与 #pragma omp 临界我没有任何问题