NOX & LOCA: Object-Oriented Nonlinear Solver and Continuation Packages



NOX is short for Nonlinear Object-Oriented Solutions, and its objective is to enable the robust and efficient solution of the equation: $ F(x)=0 $, where $F:\Re^n \rightarrow \Re^n$. NOX implements a variety of Newton-based globalization techniques including Line Search and Trust Region algorithms. In additon it provides higher and lower order models using Broyden and Tensor algorithms. Special algorithms have been developed for use with inexact linear solvers such as Krylov subspace techniques. NOX is designed to work with any linear algebra package and to be easily customized. NOX is part of Sandia's Trilinos project.

LOCA, distributed as part of NOX, is short for Library of Continuation Algorithms, and its objective is to compute families of solutions to $ F(x,p)=0 $ and their bifurcations, where $F:\Re^n\times\Re^m\rightarrow\Re^n$. For LOCA specific information, see LOCA Overview.


NOX/LOCA version 7.0 will be release as part of Trilinos 7.0 in September 2006. The libraries have undergone extensive changes. Please read the NOX and LOCA Release Information page for more details on these changes.

Technical Information


NOX is available for download under the terms of the GNU Lesser General Public License.


NOX and LOCA are packaged and released as part of the Trilinos Solver Framework. You may download NOX (which includes LOCA) by downloading a copy of Trilinos. Please see the Trilinos downloads page for the latest releases. <br />

If you are a Sandia employee you can download the development branch of Trilinos (either without repository information at the Trilinos downloads page, or directly checked-out of the repository--read about it in the Trilinos Developer Guide, the CVS page, or developer FAQ). (If you are not a Sandia employee, to gain access to either option, send a request to

Reporting Bugs and Making Enhancement Requests

To reports bugs or make enhancement requests, visit the Trilinos Bugzilla (Bug Tracking) Database, and use the following instructions.

Mailing Lists

We recommend that users and developers subscribe to the following mailing lists as appropriate.

NOX & LOCA Contributors

The following people have contributed code to NOX and/or LOCA:

For All Other Questions and Comments...

Please contact Roger Pawlowski ( or Eric Phipps (
Generated on Thu Sep 18 12:38:28 2008 for NOX by doxygen