[Solved] How to named the sub expressions?

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forza inter Registered Member Posts 3 Karma 0	[Solved] How to named the sub expressions? Mon Oct 27, 2014 8:46 am Before Eigen v3.3, i can use the following c++1y code to named the sub expressions to improve readability. However with the current version, i got "Segmentation fault (core dumped)". Code: Select all #include <iostream> #include <exception> #include <tbb/task_scheduler_init.h> #include <tbb/parallel_reduce.h> #include <tbb/blocked_range.h> #include <eigen3/Eigen/Core> int main(int argc, char* argv[]) try { using namespace std; Eigen::initParallel(); tbb::task_scheduler_init init(tbb::task_scheduler_init::default_num_threads()); const std::ptrdiff_t size(1024); const Eigen::MatrixXf m(Eigen::MatrixXf::Random(size, size)); const tbb::blocked_range<std::ptrdiff_t> range(0, size); const float ANGAST(9.2), DFA(3.2), DFB(4.6); const float result( tbb::parallel_reduce( range, float(5), [=, &m] (const tbb::blocked_range<std::ptrdiff_t> &range, const float v) -> float { for(std::ptrdiff_t i(range.begin()); i<range.end(); ++i) { const auto angdif(m.array()-ANGAST); const auto ccos((float(2)angdif).cos()); const auto df(float(.5)(DFAangdif+DFB+ccos(DFA-DFB))); const float ret(df.square().sum()); return ret; } }, [](const float lhs, const float rhs) -> const float { return lhs>rhs?lhs:rhs; })); std::cout<<"output = "<<result<<"\n"; return 0; } catch (const std::exception& e) { std::cerr << e.what() << std::endl; } catch(...) { std::cerr << "Exception of unknown type!" << std::endl; } I have to use the following, but i am still wondering are there any ways to named the sub expressions in current version? Thanks in advance. Code: Select all #include <iostream> #include <exception> #include <tbb/task_scheduler_init.h> #include <tbb/parallel_reduce.h> #include <tbb/blocked_range.h> #include <eigen3/Eigen/Core> int main(int argc, char* argv[]) try { using namespace std; Eigen::initParallel(); tbb::task_scheduler_init init(tbb::task_scheduler_init::default_num_threads()); const std::ptrdiff_t size(1024); const Eigen::MatrixXf m(Eigen::MatrixXf::Random(size, size)); const tbb::blocked_range<std::ptrdiff_t> range(0, size); const float ANGAST(9.2), DFA(3.2), DFB(4.6); const float result( tbb::parallel_reduce( range, float(5), [=, &m] (const tbb::blocked_range<std::ptrdiff_t> &range, const float v) -> float { for(std::ptrdiff_t i(range.begin()); i<range.end(); ++i) { const float ret((float(.5)(DFA(m.array()-ANGAST)+DFB+(float(2)(m.array()-ANGAST)).cos()(DFA-DFB))).square().sum()); return ret; } }, [](const float lhs, const float rhs) -> const float { return lhs>rhs?lhs:rhs; })); std::cout<<"output = "<<result<<"\n"; return 0; } catch (const std::exception& e) { std::cerr << e.what() << std::endl; } catch(...) { std::cerr << "Exception of unknown type!" << std::endl; } Last edited by forza inter on Mon Oct 27, 2014 10:03 am, edited 1 time in total.
ggael Moderator Posts 3447 Karma 19 OS	Re: How to named the sub expressions? Mon Oct 27, 2014 9:27 am can you show the backtrace, as in theory the upcoming 3.3 version should exhibit much fewer pitfalls regarding named expression.
forza inter Registered Member Posts 3 Karma 0	Re: How to named the sub expressions? Mon Oct 27, 2014 9:47 am I changed it to single thread version as below, and the result is the same ("Segmentation fault (core dumped)"). Here's the backtrace: [Thread debugging using libthread_db enabled] Using host libthread_db library "/usr/lib/libthread_db.so.1". Core was generated by `bin/v2'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x0000000000400ebc in main (argc=<optimized out>, argv=<optimized out>) at src/main.c11:10 10 const Eigen::MatrixXf m(Eigen::MatrixXf::Random(size, size)); (gdb) bt full #0 0x0000000000400ebc in main (argc=<optimized out>, argv=<optimized out>) at src/main.c11:10 m = {<Eigen::PlainObjectBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<Eigen::MatrixBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<Eigen::DenseBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<Eigen::internal::special_scalar_op_base<Eigen::Matrix<float, -1, -1, 0, -1, -1>, float, float, false>> = {<Eigen::DenseCoeffsBase<Eigen::Matrix<float, -1, -1, 0, -1, -1>, 3>> = {<Eigen::DenseCoeffsBase<Eigen::Matrix<float, -1, -1, 0, -1, -1>, 1>> = {<Eigen::DenseCoeffsBase<Eigen::Matrix<float, -1, -1, 0, -1, -1>, 0>> = {<Eigen::EigenBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, m_storage = {m_data = 0x7f8ea85dd010, m_rows = 1024, m_cols = 1024}}, <No data fields>} ANGAST = 9.19999981 DFA = 3.20000005 DFB = 4.5999999 result = 5 (gdb) bt #0 0x0000000000400ebc in main (argc=<optimized out>, argv=<optimized out>) at src/main.c11:10 (gdb) info threads Id Target Id Frame * 1 Thread 0x7f8eabf4a740 (LWP 32627) 0x0000000000400ebc in main (argc=<optimized out>, argv=<optimized out>) at src/main.c11:10 (gdb) thread apply all bt Thread 1 (Thread 0x7f8eabf4a740 (LWP 32627)): #0 0x0000000000400ebc in main (argc=<optimized out>, argv=<optimized out>) at src/main.c11:10 (gdb) thread apply all bt full Thread 1 (Thread 0x7f8eabf4a740 (LWP 32627)): #0 0x0000000000400ebc in main (argc=<optimized out>, argv=<optimized out>) at src/main.c11:10 m = {<Eigen::PlainObjectBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<Eigen::MatrixBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<Eigen::DenseBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<Eigen::internal::special_scalar_op_base<Eigen::Matrix<float, -1, -1, 0, -1, -1>, float, float, false>> = {<Eigen::DenseCoeffsBase<Eigen::Matrix<float, -1, -1, 0, -1, -1>, 3>> = {<Eigen::DenseCoeffsBase<Eigen::Matrix<float, -1, -1, 0, -1, -1>, 1>> = {<Eigen::DenseCoeffsBase<Eigen::Matrix<float, -1, -1, 0, -1, -1>, 0>> = {<Eigen::EigenBase<Eigen::Matrix<float, -1, -1, 0, -1, -1> >> = {<No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, <No data fields>}, m_storage = {m_data = 0x7f8ea85dd010, m_rows = 1024, m_cols = 1024}}, <No data fields>} ANGAST = 9.19999981 DFA = 3.20000005 DFB = 4.5999999 result = 5 (gdb) Code: Select all #include <iostream> #include <exception> #include <eigen3/Eigen/Core> int main(int argc, char* argv[]) try { using namespace std; const std::ptrdiff_t size(1024); const Eigen::MatrixXf m(Eigen::MatrixXf::Random(size, size)); const float ANGAST(9.2), DFA(3.2), DFB(4.6); float result(5); for(std::ptrdiff_t i(0); i<size; ++i) { const auto angdif(m.array()-ANGAST); const auto ccos((float(2)angdif).cos()); const auto df(float(.5)(DFAangdif+DFB+ccos(DFA-DFB))); const float ret(df.square().sum()); result = std::max(result, ret); } std::cout<<"output = "<<result<<"\n"; return 0; } catch (const std::exception& e) { std::cerr << e.what() << std::endl; } catch(...) { std::cerr << "Exception of unknown type!" << std::endl; } ggael wrote:can you show the backtrace, as in theory the upcoming 3.3 version should exhibit much fewer pitfalls regarding named expression.
ggael Moderator Posts 3447 Karma 19 OS	Re: How to named the sub expressions? Mon Oct 27, 2014 9:54 am I cannot reproduce using either clang and gcc. I also run the code within valgrind, no error. Make sure your copy of the devel branch is up-to-date.
forza inter Registered Member Posts 3 Karma 0	Re: How to named the sub expressions? Mon Oct 27, 2014 10:02 am Sorry, actually i made a mistake. Before i have a system wide eigen installation (extra/eigen 3.2.2-1), after i replaced it with the latest hg version and now it's running well. Thanks a lot.