Module topology

Organizing processes as groups and communicators

Processes are organized in communicators. All parallel processes initially partaking in the computation are organized in a context called the ‘world communicator’ which is available as a property of the Universe. From the world communicator, other communicators can be created. Processes can be addressed via their Rank within a specific communicator. This information is encapsulated in a Process.

Unfinished features

• 6.3: Group management
  • 6.3.2: Constructors, MPI_Group_range_incl(), MPI_Group_range_excl()
• 6.4: Communicator management
  • 6.4.2: Constructors, MPI_Comm_dup_with_info(), MPI_Comm_idup(), MPI_Comm_split_type()
  • 6.4.4: Info, MPI_Comm_set_info(), MPI_Comm_get_info()
• 6.6: Inter-communication
• 6.7: Caching
• 6.8: Naming objects
• 7: Process topologies
• Parts of sections: 8, 10, 12

Modules

traits

Topology traits

Structs

AnyProcess

Identifies an arbitrary process that is a member of a certain communicator, e.g. for use as a Source in point to point communication.

CartesianCommunicator

A CartesianCommunicator is an MPI communicator object where ranks are laid out in an n-dimensional cartesian space. This gives ranks neighbors in each of those dimensions, and MPI is able to optimize the layout of these ranks to improve physical locality.

CartesianLayout

Contains arrays describing the layout of the CartesianCommunicator.

Color

A color used in a communicator split

DistributedGraphCommunicator

Unimplemented

GraphCommunicator

Unimplemented

Process

Identifies a process by its Rank within a certain communicator.

SystemCommunicator

A built-in communicator, e.g. MPI_COMM_WORLD

SystemGroup

A built-in group, e.g. MPI_GROUP_EMPTY

UserCommunicator

A user-defined communicator

UserGroup

A user-defined group of processes

Enums

CommunicatorRelation

The relation between two communicators.

GroupRelation

The relation between two groups.

IntoTopology

An enum indirecting between different concrete communicator topology types

Topology

An enum describing the topology of a communicator

Traits

AsCommunicator

Something that has a communicator associated with it

Communicator

Communicators are contexts for communication

Group

Groups are collections of parallel processes

Type Aliases

Key

A key used when determining the rank order of processes after a communicator split.

Rank

Identifies a certain process within a communicator.