Center for Applied Scientific Computing, Lawrence Livermore National Laboratory

SUNDIALS is a family of software packages implemented with the goal of providing robust time integrators and nonlinear solvers that can easily be incorporated into existing simulation codes. The primary design goals are to require minimal information from the user, allow users to easily supply their own data structures underneath the packages, and allow for easy incorporation of user-supplied linear solvers and preconditioners. The various packages share many subordinate modules and are organized as a family with a directory structure that exploits sharing common functionality.

The SUNDIALS suite consists of the following packages:

• ARKODE - for integration of stiff, nonstiff, and multirate ordinary differential equation systems (ODEs) of the form

  M y' = f1(t,y) + f2(t,y), y(t0) = y0

• CVODE - for integration of stiff and nonstiff ordinary differential equation systems (ODEs) of the form

  y' = f(t,y), y(t0) = y0

• CVODES - for integration and sensitivity analysis (forward and adjoint) of ordinary differential equation systems (ODEs) of the form

  y' = f(t,y,p), y(t0) = y0(p)

• IDA - for integration of differential-algebraic equation systems (DAEs) of the form

  F(t,y,y') = 0, y(t0) = y0, y'(t0) = y0'

• IDAS - for integration and sensitivity analysis (forward and adjoint) of differential-algebraic equation systems (DAEs) of the form

  F(t,y,y',p) = 0, y(t0) = y0(p), y'(t0) = y0'(p)

• KINSOL - for solution of nonlinear algebraic systems of the form

  F(u) = 0

For installation directions see the INSTALL_GUIDE or the installation chapter in any of the package user guides.

Warning to users who receive more than one of the individual packages at different times: Mixing old and new versions of SUNDIALS may fail. To avoid such failures, obtain all desired package at the same time.

Full user guides for SUNDIALS packages are provided in the doc directory along with documentation for example programs.

A list of Frequently Asked Questions on build and installation procedures as well as common usage issues is available on the SUNDIALS FAQ. For dealing with systems with unphysical solutions or discontinuities see the SUNDIALS usage notes.

If you have a question not covered in the FAQ or usage notes, please submit your question to the SUNDIALS mailing list.

Bug fixes or minor changes are preferred via a pull request to the SUNDIALS GitHub repository. For more information on contributing see the CONTRIBUTING file.

Information on recent changes to SUNDIALS can be found in the "Introduction" chapter of each package's user guide and a complete release history is available in the "SUNDIALS Release History" appendix of each user guide.

The SUNDIALS Team: Carol S. Woodward, Daniel R. Reynolds, Alan C. Hindmarsh, David J. Gardner, and Cody J. Balos. We thank Radu Serban for significant and critical past contributions.

We also acknowledge past contributions of Scott D. Cohen, Peter N. Brown, George Byrne, Allan G. Taylor, Steven L. Lee, Keith E. Grant, Aaron Collier, Lawrence E. Banks, Steve Smith, Cosmin Petra, Slaven Peles, John Loffeld, Dan Shumaker, Ulrike Yang, James Almgren-Bell, Shelby L. Lockhart, Hilari C. Tiedeman, Ting Yan, Jean M. Sexton, and Chris White.

We ask users of SUNDIALS to cite the following paper in any publications reporting work done with SUNDIALS:

• Alan C. Hindmarsh, Peter N. Brown, Keith E. Grant, Steven L. Lee, Radu Serban, Dan E. Shumaker, and Carol S. Woodward. 2005. SUNDIALS: Suite of nonlinear and differential/algebraic equation solvers. ACM Trans. Math. Softw. 31, 3 (September 2005), 363-396. DOI=http://dx.doi.org/10.1145/1089014.1089020

SUNDIALS is released under the BSD 3-clause license. See the LICENSE and NOTICE files for details. All new contributions must be made under the BSD 3-clause license.

Please Note If you are using SUNDIALS with any third party libraries linked in (e.g., LAPACK, KLU, SuperLU_MT, PETSc, or hypre), be sure to review the respective license of the package as that license may have more restrictive terms than the SUNDIALS license.

SPDX-License-Identifier: BSD-3-Clause

LLNL-CODE-667205  (ARKODE)
UCRL-CODE-155951  (CVODE)
UCRL-CODE-155950  (CVODES)
UCRL-CODE-155952  (IDA)
UCRL-CODE-237203  (IDAS)
LLNL-CODE-665877  (KINSOL)