team_thread.hpp

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Specifications for A Team of AD Threads

Syntax

include "team_thread.hpp"
ok = team_create ( num_threads )
ok = team_work ( worker )
ok = team_destroy ()
name = team_name ()

Purpose

These routines start, use, and stop a team of threads that can be used with the CppAD type AD<double> . For example, these could be OpenMP threads, pthreads, or Boost threads to name a few.

Restrictions

Calls to the routines team_create , team_work , and team_destroy , must all be done by the master thread; i.e., thread_num must be zero. In addition, they must all be done in sequential execution mode; i.e., when the master thread is the only thread that is running (in_parallel must be false).

team_create

The argument num_threads > 0 has type size_t and specifies the number of threads in this team. This initializes both AD<double> and team_work to be used with num_threads . If num_threads > 1 , num_threads - 1 new threads are created and put in a waiting state until team_work is called.

team_work

This routine may be called one or more times between the call to team_create and team_destroy . The argument worker has type bool worker ( void ) . Each call to team_work runs num_threads versions of worker with the corresponding value of thread_num between zero and num_threads - 1 and different for each thread,

team_destroy

This routine terminates all the other threads except for thread number zero; i.e., it terminates the threads corresponding to

thread_num = 1 , … , num_threads -1

team_name

This routines returns a name that identifies this threading system. The return value has prototype

const char * name

and is a statically allocated '\0' terminated C string.

ok

The return value ok has type bool . It is false if an error is detected during the corresponding call. Otherwise it is true .

Example Use

Example use of these specifications can be found in the file team_example.cpp .

Example Implementation

Example implementations of these specifications can be found in the files:

team_openmp.cpp

OpenMP Implementation of a Team of AD Threads

team_bthread.cpp

Boost Thread Implementation of a Team of AD Threads

team_pthread.cpp

Pthread Implementation of a Team of AD Threads

Speed Test of Implementation

Speed tests of using CppAD with the team implementations above can be found in:

harmonic.cpp

Multi-Threading Harmonic Summation Example / Test

multi_newton.cpp

Multi-Threaded Newton Method Example / Test

Source

# include <cstddef> // for size_t

extern bool team_create(size_t num_threads);
extern bool team_work(void worker(void));
extern bool team_destroy(void);
extern const char* team_name(void);