The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform

Ute Ebert - One of the best experts on this subject based on the ideXlab platform.

  • afivo a framework for quadtree octree amr with shared memory parallelization and geometric multigrid methods
    Computer Physics Communications, 2018
    Co-Authors: Jannis Teunissen, Ute Ebert
    Abstract:

    Abstract Afivo is a framework for simulations with adaptive mesh refinement (AMR) on quadtree (2D) and octree (3D) grids. The framework comes with a geometric multigrid solver, shared-memory (Openmp) Parallelism and it supports output in Silo and VTK file formats. Afivo can be used to efficiently simulate AMR problems with up to about 1 0 8 unknowns on desktops, workstations or single compute nodes. For larger problems, existing distributed-memory frameworks are better suited. The framework has no built-in functionality for specific physics applications, so users have to implement their own numerical methods . The included multigrid solver can be used to efficiently solve elliptic partial differential equations such as Poisson’s equation. Afivo’s design was kept simple, which in combination with the shared-memory Parallelism facilitates modification and experimentation with AMR algorithms. The framework was already used to perform 3D simulations of streamer discharges , which required tens of millions of cells. Program summary Program Title: Afivo Program Files doi: http://dx.doi.org/10.17632/5y43rjdmxd.1 Licensing provisions: GPLv3 Programming language: Fortran 2011 External routines/libraries: Silo (LLNL) Nature of problem: Performing multiscale simulations, especially those requiring a fast elliptic solver. Solution method: Provide a framework for parallel simulations on adaptively refined quadtree/octree grids, including a geometric multigrid solver. Unusual features: The framework uses shared-memory Parallelism (Openmp) instead of MPI.

  • Afivo : a framework for quadtree/octree AMR with shared-memory parallelization and geometric multigrid methods
    Computer Physics Communications, 2018
    Co-Authors: Jannis Teunissen, Ute Ebert
    Abstract:

    Abstract Afivo is a framework for simulations with adaptive mesh refinement (AMR) on quadtree (2D) and octree (3D) grids. The framework comes with a geometric multigrid solver, shared-memory (Openmp) Parallelism and it supports output in Silo and VTK file formats. Afivo can be used to efficiently simulate AMR problems with up to about 1 0 8 unknowns on desktops, workstations or single compute nodes. For larger problems, existing distributed-memory frameworks are better suited. The framework has no built-in functionality for specific physics applications, so users have to implement their own numerical methods . The included multigrid solver can be used to efficiently solve elliptic partial differential equations such as Poisson’s equation. Afivo’s design was kept simple, which in combination with the shared-memory Parallelism facilitates modification and experimentation with AMR algorithms. The framework was already used to perform 3D simulations of streamer discharges , which required tens of millions of cells. Program summary Program Title: Afivo Program Files doi: http://dx.doi.org/10.17632/5y43rjdmxd.1 Licensing provisions: GPLv3 Programming language: Fortran 2011 External routines/libraries: Silo (LLNL) Nature of problem: Performing multiscale simulations, especially those requiring a fast elliptic solver. Solution method: Provide a framework for parallel simulations on adaptively refined quadtree/octree grids, including a geometric multigrid solver. Unusual features: The framework uses shared-memory Parallelism (Openmp) instead of MPI.

  • Simulating streamer discharges in 3D with the parallel adaptive Afivo framework
    Journal of Physics D: Applied Physics, 2017
    Co-Authors: Jannis Teunissen, Ute Ebert
    Abstract:

    We present an open-source plasma fluid code for 2D, cylindrical and 3D simulations of streamer discharges. The code is based on the Afivo framework, which features adaptive mesh refinement on quadtree/octree grids, geometric multigrid methods for Poisson's equation, and Openmp Parallelism. We describe the numerical implementation of a fluid model of the drift-diffusion-reaction type, combined with the local field approximation. Then we demonstrate its functionality with 3D simulations of long positive streamers in nitrogen in undervolted gaps. Three examples are presented. The first one shows how a stochastic background density affects streamer propagation and branching. The second one focuses on the interaction of a streamer with preionized regions, and the third one investigates the interaction between two streamers. The simulations use up to 108 grid cells and run in less than a day; without mesh refinement they would require more than grid cells.

Jannis Teunissen - One of the best experts on this subject based on the ideXlab platform.

  • afivo a framework for quadtree octree amr with shared memory parallelization and geometric multigrid methods
    Computer Physics Communications, 2018
    Co-Authors: Jannis Teunissen, Ute Ebert
    Abstract:

    Abstract Afivo is a framework for simulations with adaptive mesh refinement (AMR) on quadtree (2D) and octree (3D) grids. The framework comes with a geometric multigrid solver, shared-memory (Openmp) Parallelism and it supports output in Silo and VTK file formats. Afivo can be used to efficiently simulate AMR problems with up to about 1 0 8 unknowns on desktops, workstations or single compute nodes. For larger problems, existing distributed-memory frameworks are better suited. The framework has no built-in functionality for specific physics applications, so users have to implement their own numerical methods . The included multigrid solver can be used to efficiently solve elliptic partial differential equations such as Poisson’s equation. Afivo’s design was kept simple, which in combination with the shared-memory Parallelism facilitates modification and experimentation with AMR algorithms. The framework was already used to perform 3D simulations of streamer discharges , which required tens of millions of cells. Program summary Program Title: Afivo Program Files doi: http://dx.doi.org/10.17632/5y43rjdmxd.1 Licensing provisions: GPLv3 Programming language: Fortran 2011 External routines/libraries: Silo (LLNL) Nature of problem: Performing multiscale simulations, especially those requiring a fast elliptic solver. Solution method: Provide a framework for parallel simulations on adaptively refined quadtree/octree grids, including a geometric multigrid solver. Unusual features: The framework uses shared-memory Parallelism (Openmp) instead of MPI.

  • Afivo : a framework for quadtree/octree AMR with shared-memory parallelization and geometric multigrid methods
    Computer Physics Communications, 2018
    Co-Authors: Jannis Teunissen, Ute Ebert
    Abstract:

    Abstract Afivo is a framework for simulations with adaptive mesh refinement (AMR) on quadtree (2D) and octree (3D) grids. The framework comes with a geometric multigrid solver, shared-memory (Openmp) Parallelism and it supports output in Silo and VTK file formats. Afivo can be used to efficiently simulate AMR problems with up to about 1 0 8 unknowns on desktops, workstations or single compute nodes. For larger problems, existing distributed-memory frameworks are better suited. The framework has no built-in functionality for specific physics applications, so users have to implement their own numerical methods . The included multigrid solver can be used to efficiently solve elliptic partial differential equations such as Poisson’s equation. Afivo’s design was kept simple, which in combination with the shared-memory Parallelism facilitates modification and experimentation with AMR algorithms. The framework was already used to perform 3D simulations of streamer discharges , which required tens of millions of cells. Program summary Program Title: Afivo Program Files doi: http://dx.doi.org/10.17632/5y43rjdmxd.1 Licensing provisions: GPLv3 Programming language: Fortran 2011 External routines/libraries: Silo (LLNL) Nature of problem: Performing multiscale simulations, especially those requiring a fast elliptic solver. Solution method: Provide a framework for parallel simulations on adaptively refined quadtree/octree grids, including a geometric multigrid solver. Unusual features: The framework uses shared-memory Parallelism (Openmp) instead of MPI.

  • Simulating streamer discharges in 3D with the parallel adaptive Afivo framework
    Journal of Physics D: Applied Physics, 2017
    Co-Authors: Jannis Teunissen, Ute Ebert
    Abstract:

    We present an open-source plasma fluid code for 2D, cylindrical and 3D simulations of streamer discharges. The code is based on the Afivo framework, which features adaptive mesh refinement on quadtree/octree grids, geometric multigrid methods for Poisson's equation, and Openmp Parallelism. We describe the numerical implementation of a fluid model of the drift-diffusion-reaction type, combined with the local field approximation. Then we demonstrate its functionality with 3D simulations of long positive streamers in nitrogen in undervolted gaps. Three examples are presented. The first one shows how a stochastic background density affects streamer propagation and branching. The second one focuses on the interaction of a streamer with preionized regions, and the third one investigates the interaction between two streamers. The simulations use up to 108 grid cells and run in less than a day; without mesh refinement they would require more than grid cells.

Kasper J. - One of the best experts on this subject based on the ideXlab platform.

  • The Chronus Quantum software package
    eScholarship University of California, 2020
    Co-Authors: David B. Williams-young, Petrone A., Sun S., Lestrange P., Koulias L., Wildman A., Torin F. Stetina, Ce Hoyer, Nascimento Dr, Kasper J.
    Abstract:

    © 2019 Wiley Periodicals, Inc. The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge-including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided. This article is categorized under: Software > Quantum Chemistry Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

  • The Chronus Quantum software package
    'Wiley', 2020
    Co-Authors: Williams-young D. B., Petrone A., Sun S., Stetina T. F., Lestrange P., Hoyer C. E., Nascimento D. R., Koulias L., Wildman A., Kasper J.
    Abstract:

    The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge‐including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided

  • The Chronus Quantum software package
    eScholarship University of California, 2020
    Co-Authors: David B. Williams-young, Petrone A., Sun S., Lestrange P., Koulias L., Wildman A., Torin F. Stetina, Ce Hoyer, Nascimento Dr, Kasper J.
    Abstract:

    The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge-including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided. This article is categorized under: Software > Quantum Chemistry Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

Kasper Joseph - One of the best experts on this subject based on the ideXlab platform.

  • Chronus Quantum software package
    'Wiley', 2020
    Co-Authors: Williams‐young, David B., Stetina T. F., Hoyer C. E., Nascimento D. R., Petrone Alessio, Sun Shichao, Lestrange Patrick, Koulias Lauren, Wildman Andrew, Kasper Joseph
    Abstract:

    The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge‐including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided

  • The Chronus Quantum (ChronusQ) Software Package
    'Wiley', 2019
    Co-Authors: Williams-young, David B., Stetina T. F., Hoyer C. E., Nascimento D. R., Petrone Alessio, Sun Shichao, Lestrange Patrick, Koulias Lauren, Wildman Andrew, Kasper Joseph
    Abstract:

    The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge-including atomic orbitals (GIAO). ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing (MPI) and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided.Comment: 43 pages, 2 figure

David B. Williams-young - One of the best experts on this subject based on the ideXlab platform.

  • The Chronus Quantum software package
    eScholarship University of California, 2020
    Co-Authors: David B. Williams-young, Petrone A., Sun S., Lestrange P., Koulias L., Wildman A., Torin F. Stetina, Ce Hoyer, Nascimento Dr, Kasper J.
    Abstract:

    © 2019 Wiley Periodicals, Inc. The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge-including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided. This article is categorized under: Software > Quantum Chemistry Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

  • The Chronus Quantum software package
    eScholarship University of California, 2020
    Co-Authors: David B. Williams-young, Petrone A., Sun S., Lestrange P., Koulias L., Wildman A., Torin F. Stetina, Ce Hoyer, Nascimento Dr, Kasper J.
    Abstract:

    The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge-including atomic orbitals. ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing implementation and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided. This article is categorized under: Software > Quantum Chemistry Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

  • The Chronus Quantum (ChronusQ) Software Package.
    WIREs Computational Molecular Science, 2019
    Co-Authors: David B. Williams-young, Alessio Petrone, Shichao Sun, Torin F. Stetina, Patrick J. Lestrange, Chad E. Hoyer, Daniel R. Nascimento, Lauren Koulias, Andrew Wildman, Joseph M. Kasper
    Abstract:

    The Chronus Quantum (ChronusQ) software package is an open source (under the GNU General Public License v2) software infrastructure which targets the solution of challenging problems that arise in ab initio electronic structure theory. Special emphasis is placed on the consistent treatment of time dependence and spin in the electronic wave function, as well as the inclusion of relativistic effects in said treatments. In addition, ChronusQ provides support for the inclusion of uniform finite magnetic fields as external perturbations through the use of gauge-including atomic orbitals (GIAO). ChronusQ is a parallel electronic structure code written in modern C++ which utilizes both message passing (MPI) and shared memory (Openmp) Parallelism. In addition to the examination of the current state of code base itself, a discussion regarding ongoing developments and developer contributions will also be provided.