Each Trilinos package is a self-contained, independent piece of software with its own set of requirements, its own development team and group of users. Because of this, Trilinos itself is designed to respect the autonomy of packages. Trilinos offers a variety of ways for a particular package to interact with other Trilinos packages. It also offers a set of tools that can assist package developers with builds across multiple platforms, generating documentation and regression testing across a set of target platforms. At the same time, what a package must do to be called a Trilinos package is minimal, and varies with each package.

Basic Linear Algebra Libraries

  • Epetra - Core linear algebra package. Facilitates construction and manipulation of distributed and serial graphs, sparse and dense matrices, vectors and multivectors.

  • EpetraExt - Extensions to the core linear algebra package, Epetra.

  • Tpetra - Next-generation, templated version of Petra, taking advantage of the newer advanced features of C++.

  • Jpetra - Experimental Java version of the Petra library.

  • Kokkos - Core kernel package.

Preconditioners

  • AztecOO - ILU-type preconditioner. See also description under "Linear Solvers."

  • IFPACK - Distributed algebraic preconditioner package. Includes incomplete factorizations and relaxation-based preconditioners in domain decomposition framework. Compatible with AztecOO.

  • ML - Multilevel, distributed memory algebraic preconditioners. Provides multi-level, multigrid-like preconditioners for distributed linear systems. Compatible with AztecOO.

  • Meros - Segregated preconditioning package. Provides scalable block preconditioning for problems that coupled simultaneous solution variables such as Navier-Strokes problems.

Solvers

Linear Solvers

  • Epetra - Provides wrappers for select BLAS and LAPACK routines. See also description under "Basic Linear Algebra Libraries."

  • Teuchos - Provides wrappers for select BLAS and LAPACK routines. See also description under "Basic Linear Algebra Libraries."

  • Pliris - An object-oriented interface to a LU solver for dense matrices on parallel platforms.

  • AztecOO - Preconditioned Krylov solver package. Supercedes Aztec 2.1. Solves linear systems of equations via preconditioned Krylov methods. Uses Epetra objects, compatible with IFPACK, ML and Aztec.

  • Belos - Next-generation iterative solvers written using a traits interface, meaning that it has no explicit dependence on any concrete linear algebra library. Instead, it can be used with any concrete linear algebra library that implements the Thyra abstract interfaces and even Epetra directly.

  • Komplex - Complex linear solver package. Solves complex-valued linear systems via equivalent real formulations.

  • Amesos - Direct solver classes. Supports use of a growing list of third party direct solvers, including DSCPACK, SuperLU, SuperLUDist and UMFPACK. Compatible with Epetra.

Nonlinear Solvers

  • NOX - Nonlinear solver package. Abstract and concrete classes for construction and solution of nonlinear problems.

  • LOCA - LOCA is a software library for performing bifurcation analysis of large-scale applications. When implemented with an application code, LOCA enables the tracking of solution branches as a function of system parameters and the direct tracking of bifurcation points. LOCA is designed to drive application codes that use Newton's method to locate steady-state solutions to nonlinear problems.

  • MOOCHO - MOOCHO (Multifunctional Object-Oriented arCHitecture for Optimization) is designed to solve large-scale, equality and inequality nonlinearly constrained, non-convex optimization problems (i.e. nonlinear programs) using reduced-space successive quadratic programming (SQP) methods.

  • Rythmos - Rythmos is a transient integrator for ordinary differential equations and differential-algebraic equations with support for explicit, implicit, one-step and multi-step algorithms. The fundamental design of Rythmos is aimed at supporting operator-split algorithms, multi-physics applications, block linear algebra, and adjoint integration.

Eigensolvers

  • Anasazi - Anasazi is an extensible and interoperable framework for large-scale eigenvalue algorithms. The motivation for this framework is to provide a generic interface to a collection of algorithms for solving large-scale eigenvalue problems. Anasazi is interoperable because both the matrix and vectors (defining the eigenspace) are considered to be opaque objects---only knowledge of the matrix and vectors via elementary operations is necessary. An implementation of Anasazi is accomplished via the use of interfaces. Current interfaces available include Epetra and so any libraries that understand Epetra matrices and vectors (such as AztecOO) may also be used in conjunction with Anasazi.

Automatic Differentiation

  • Sacado - Sacado is a package for automatic differentiation of C++ programs It provides simple yet fast and efficient classes for forward, revers and Taylor polynomial mode automatic differentiation using C++ template and operator overloading. The resulting derivatives can be leverage in numerous ways including nonlinear solves with NOX continuation and bifurcation analysis with LOCA optimization with MOOCHO, and time integration wit Rythmos.

Domain Decomposition

Domain Decomposition

  • Claps - Claps is a collection of domain decomposition preconditioners and solvers.

Mortar Methods

  • Moertel - Mortar methods that can be used in a large class of nonconforming situations such as the surface coupling of different physical models, discretization schemes or non-matching triangulations along interior interfaces of a domain.

Repartitioning / Rebalancing

  • Isorropia - Isorropia is a repartitioning/rebalancing package, intended to assist with redistributing objects such as matrices and matrix-graphs in a parallel execution setting, to allow for more efficient computations. Isorropia is primarily an interface to the Zoltan library, but can be built and used with minimal capability without Zoltan.

Abstract Interfaces and Adapters

  • Thyra - Abstract linear solver package. Replaces the now-deprecated TSF family.

  • PyTrilinos - Python interfaces to selected Trilinos packages.

  • WebTrilinos - Web interface to experiment with Trilinos through a browser.

  • Stratimikos - The package Stratimikos contains a unified set of Thyra-based wrappers to linear solver and preconditioner capabilities in Trilinos. The name Stratimikos was created from the Greek words "stratigiki" and "grammikos" which which mean "strategy" and "linear in English. The word "stratimikos" itself has not real meaning itself. The Stratimikos package is also a place where unified testing of linear solvers and preconditioners can be performed.

Utilities

  • Teuchos - Common tools package.

  • TriUtils - TriUtils is a package of utilites used by many of the Trilinos packages.

  • EpetraExt - Matrix/Vector read/write utilities. See also description under "Basic Linear Algebra Libraries."

  • RTOp - RTOp (reduction/transformation operators) provides the basic mechanism for implementing vector operations in a flexible and efficient manner.

  • Galeri - Galeri is a package for generating linear systems used by many of the Trilinos packages for examples and tests.

Instructional

  • Didasko - Didasko is the Trilinos tutorial, and contains several examples, detailed descriptions, tips, and suggestions for most Trilinos packages.

  • New_Package - A sample Trilinos package containing all of the infrastructure to install a new package into the Trilinos framework. Contains the basic directory structure, a collection of sample configuration and build files and a sample "Hello World" package.