Introduction to Tifpack

Tifpack provides templated preconditioning algorithms using linear algebra objects (matrices, operators, multivectors) provided by the Tpetra package.

Tifpack will (when finished) provide the same functionality as the Ifpack package (which uses Epetra linear algebra objects).

Overview of Tifpack

Templated Types in Tifpack

All classes in Tifpack utilize templates. Most of the preconditioner classes are templated on the type of the input matrix. This allows the user to provide any Tpetra matrix (i.e., templated on any of the Scalar/Ordinal/Node/etc types that are possible with Tpetra).

Tifpack Preconditioners

All Tifpack preconditioners inherit the base class Tifpack::Preconditioner.

The preconditioners that are supported in the current release are:

• Tifpack::Diagonal
• Tifpack::Relaxation
• Tifpack::Chebyshev
• Tifpack::ILUT
• Tifpack::RILUK

Trilinos and Tifpack

Tifpack preconditioners can be used with the solver algorithms in the Trilinos/Belos package.

Examples

A test program (tifpack/test/belos) is provided which demonstrates creating and using Tifpack preconditioners with Belos solvers. The test program is entirely driven by XML input files, which specify the matrix file to be used, as well as parameters for the preconditioner, and the belos solver, etc.