Trilinos is a collection of over 50 computational science software libraries written in C++. The libraries are independently developed yet strive for interoperability when it makes technical sense, and share software quality tools and processes such as a common build system, release schedule, and test harness. The core capabilities in Trilinos include linear solvers and preconditioners (e.g. ML, ShyLU), nonlinear solvers and other analysis algorithms (e.g. NOX), and partitioning, load balancing, and data ordering algorithms (e.g. Zoltan); these are explicitly supported by FASTMath. When using these tools in science applications, a wider range of libraries are also available through Trilinos, including finite element discretization tools, automatic differentiation technology, optimization algorithms and uncertainty quantification tools, and an adaptivity-enabled mesh database. A build process and software interface between Trilinos and Dakota, the main delivery vehicle of the QUEST Institute, is maintained.

Usage and applications: Trilinos tools are used throughout the Department of Energy complex, in Department of Defense applications, and at universities worldwide.