Partitioning and Load-Balancing

Contents

• Overview of Partitioning with Zoltan2
• Partitioning Functionality
• Partitioning Examples

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Overview of Partitioning with Zoltan2

Here we describe a typical way a user might use Zoltan2 for partitioning.

1. Create a Zoltan2::InputAdapter object for your data. This adapter provides a uniform interface to user data for the Zoltan2 library. Adapter interfaces exist for the following classes of data:
   • Zoltan2::MatrixInput (a row oriented matrix with optional row weights)
   • Zoltan2::GraphInput (an undirected weighted graph)
   • Zoltan2::VectorInput (a single or multi-vector with optional weights, also used for geometric coordinates)
   • Zoltan2::IdentifierInput (simple collection of identifiers)
   • Zoltan2::MeshInput: available soon.
2. Create a Teuchos::ParameterList with your Zoltan2 parameters. If you are using a third party library (PT-Scotch, ParMetis) you can include a sublist of parameters for this library. See z2_parameters for a detailed list of parameters.
3. Create a Zoltan2::PartitioningProblem. It is templated on your Zoltan2::InputAdapter type. The constructor arguments are typically your input adapter and your parameter list.
4. Call Zoltan2::PartitioningProblem::solve().
5. Obtain a Zoltan2::PartitioningSolution object from the Zoltan2::PartitioningProblem using the getSolution() function.

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Partitioning Functionality

Partitioning functionality that is available now is:

• Block partitioning for simple weighted identifiers (really created as a sample algorithm).
• Multi-Jagged Coordinate Partitioning (MJ) Multi-jagged for weighted geometric coordinates.
• Recursive Coordinate Bisection (RCB) for weighted geometric coordinates.
• Graph partitioning with PTScotch for undirected weighted graphs.
• Graph partitioning with ParMETIS for undirected weighted graphs.
• Graph partitioning with Sphynx for undirected weighted graphs.

These algorithms are all parallel.

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Partitioning Examples

Examples include the following:

• Block partitioning (block.cpp)
• RCB partitioning for a C++ novice (rcb_C.cpp)

Obtaining partition quality

Repartitioning