| Prev | Next |  |  |  |  |  | team_openmp.cpp | Headings

OpenMP Implementation of a Team of AD Threads
See team_thread.hpp for this routines specifications. `

    # include <omp.h>
    # include <cppad/cppad.hpp>
    # include "../team_thread.hpp"

    namespace {
         using CppAD::thread_alloc;

         // number of threads in this team
         size_t num_threads_;

         // used to inform CppAD when we are in parallel execution mode
         bool in_parallel(void)
         {     return omp_in_parallel() != 0; }

         // used to inform CppAD of the current thread number
         size_t thread_num(void)
         {     return static_cast<size_t>( omp_get_thread_num() ); }
    }

    bool team_create(size_t num_threads)
    {
         bool ok = ! in_parallel();
         ok     &= thread_num() == 0;;
         ok     &= num_threads > 0;

         // Turn off dynamic thread adjustment
         omp_set_dynamic(0);

         // Set the number of OpenMP threads
         omp_set_num_threads( int(num_threads) );

         // setup for using CppAD::AD<double> in parallel
         thread_alloc::parallel_setup(num_threads, in_parallel, thread_num);
         thread_alloc::hold_memory(true);
         CppAD::parallel_ad<double>();

         // inform team_work of number of threads
         num_threads_ = num_threads;

         return ok;
    }

    bool team_work(void worker(void))
    {     bool ok = ! in_parallel();
         ok     &= thread_num() == 0;;
         ok     &= num_threads_ > 0;

         int number_threads = int(num_threads_);
         int thread_num;
    # pragma omp parallel for
         for(thread_num = 0; thread_num < number_threads; thread_num++)
              worker();
    // end omp parallel for

         return ok;
    }

    bool team_destroy(void)
    {     bool ok = ! in_parallel();
         ok     &= thread_num() == 0;;
         ok     &= num_threads_ > 0;

         // inform team_work of number of threads
         num_threads_ = 1;

         // Set the number of OpenMP threads to one
         omp_set_num_threads( int(num_threads_) );

         // inform CppAD no longer in multi-threading mode
         thread_alloc::parallel_setup(num_threads_, CPPAD_NULL, CPPAD_NULL);
         thread_alloc::hold_memory(false);
         CppAD::parallel_ad<double>();

         return ok;
    }

    const char* team_name(void)
    {     return "openmp"; }

`

Input File: example/multi_thread/openmp/team_openmp.cpp