MULTITASK_OPENMP
Carrying Out Multiple "Tasks" in OpenMP


MULTITASK_OPENMP, a C++ code which demonstrates how to "multitask", that is, to execute several unrelated and distinct tasks simultaneously, using OpenMP for parallel execution.

This program demonstrates how OpenMP can be used for multitasking, that is, a simple kind of parallel processing in which a certain number of perhaps quite unrelated tasks must be done.

The OpenMP SECTIONS directive identifies the portion of the program where the code for these tasks is given.

The OpenMP SECTION directive is used repeatedly to divide this area of the program into independent tasks.

The code will get the benefit of parallel processing up to the point where there are as many threads as there are tasks.

The code will get a substantial speedup if the tasks take roughly the same amount of time. However, if one task takes substantially more time than the others, this results in a limit to the parallel speedup that is possible.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

MULTITASK_OPENMP is available in a C version and a C++ version and a FORTRAN90 version.

Related Data and Programs:

DIJKSTRA_OPENMP, a C++ code which uses OpenMP to parallelize a simple example of Dijkstra's minimum distance algorithm for graphs.

FFT_OPENMP, a C++ code which demonstrates the computation of a Fast Fourier Transform in parallel, using OpenMP.

HEATED_PLATE_OPENMP, a C++ code which solves the steady (time independent) heat equation in a 2D rectangular region, using OpenMP to run in parallel.

HELLO_OPENMP, a C++ code which prints out "Hello, world!" using the OpenMP parallel programming environment.

JACOBI_OPENMP, a C++ code which illustrates the use of the OpenMP application program interface to parallelize a Jacobi iteration solving A*x=b.

MD_OPENMP, a C++ code which carries out a molecular dynamics simulation in parallel, using OpenMP.

MULTITASK_MPI, a C++ code which demonstrates how to "multitask", that is, to execute several unrelated and distinct tasks simultaneously, using MPI for parallel execution.

multitask_openmp_test

MXM_OPENMP, a C++ code which computes a dense matrix product C=A*B, using OpenMP for parallel execution.

openmp_test, C++ codes which illustrate the use of the OpenMP application program interface for carrying out parallel computations in a shared memory environment.

POISSON_OPENMP, a C++ code which computes an approximate solution to the Poisson equation in a rectangle, using the Jacobi iteration to solve the linear system, and OpenMP to carry out the Jacobi iteration in parallel.

PRIME_OPENMP, a C++ code which counts the number of primes between 1 and N, using OpenMP for parallel execution.

QUAD_OPENMP, a C++ code which approximates an integral using a quadrature rule, and carries out the computation in parallel using OpenMP.

RANDOM_OPENMP, a C++ code which illustrates how a parallel program using OpenMP can generate multiple distinct streams of random numbers.

SATISFY_OPENMP, a C++ code which demonstrates, for a particular circuit, an exhaustive search for solutions of the circuit satisfy problem, using OpenMP for parallel execution.

SCHEDULE_OPENMP, a C++ code which demonstrates the default, static, and dynamic methods of "scheduling" loop iterations in OpenMP to avoid work imbalance.

SGEFA_OPENMP is a C++ code which reimplements the SGEFA/SGESL linear algebra routines from LINPACK for use with OpenMP.

ZIGGURAT_OPENMP, a C++ code which demonstrates how the ZIGGURAT library can be used to generate random numbers in an OpenMP parallel program.

Reference:

  1. Peter Arbenz, Wesley Petersen,
    Introduction to Parallel Computing - A practical guide with examples in C,
    Oxford University Press,
    ISBN: 0-19-851576-6,
    LC: QA76.58.P47.
  2. Rohit Chandra, Leonardo Dagum, Dave Kohr, Dror Maydan, Jeff McDonald, Ramesh Menon,
    Parallel Programming in OpenMP,
    Morgan Kaufmann, 2001,
    ISBN: 1-55860-671-8,
    LC: QA76.642.P32.
  3. Barbara Chapman, Gabriele Jost, Ruud vanderPas, David Kuck,
    Using OpenMP: Portable Shared Memory Parallel Processing,
    MIT Press, 2007,
    ISBN13: 978-0262533027.
  4. OpenMP Architecture Review Board,
    OpenMP Application Program Interface,
    Version 3.0,
    May 2008.

Source Code:


Last revised on 27 March 2020.