comm::CommMPI struct

MPI-based communication manager.

Manages MPI communication between ranks, handling serialization, asynchronous operations, and message dispatch

Public types

class BufferIntInterpreter: Helper class for interpreting buffer headers.

Public functions

void init(int& argc, char**& argv, MPI_Comm comm = MPI_COMM_NULL): Initialize CommMPI.
auto clone(bool dup_comm = true) const -> CommMPI: Clone the communicator to create a distinct termination scope.
auto numRanks() const -> int: Get the number of ranks in the communicator.
auto getRank() const -> int: Get this process's rank.
void finalize(): Finalize MPI.
void barrier(): MPI barrier.
template<typename T> auto registerInstanceCollective(T* obj) -> ClassHandle<T>: Register an instance for collective operations.
void unregisterInstanceCollective(std::size_t idx): Unregister a previously registered instance.
auto getInstanceCollective(std::size_t idx) -> void*: Get a registered instance by index.
template<auto fn, typename ProxyT, typename... Args> void send(int dest, ProxyT proxy, Args && ... args): Send data to a destination rank.
auto poll() -> bool: Poll for incoming messages and process them.
template<typename T> auto allgather(T const* sendbuf, int sendcount) -> std::unordered_map<int, std::vector<T>>: Gather values from all ranks, with varying counts per rank, and remember per-rank contribution.

Function documentation

void comm::CommMPI::init(int& argc, char**& argv, MPI_Comm comm = MPI_COMM_NULL)

Initialize CommMPI.

Parameters
argc	Pointer to argument count
argv	Pointer to argument array
comm	MPI communicator to use (default: MPI_COMM_NULL)

CommMPI comm::CommMPI::clone(bool dup_comm = true) const

Clone the communicator to create a distinct termination scope.

Parameters
dup_comm	Whether to duplicate the underlying MPI_Comm (default: true)
Returns	A new CommMPI instance with the cloned communicator

int comm::CommMPI::numRanks() const

Get the number of ranks in the communicator.

Returns	Number of ranks

int comm::CommMPI::getRank() const

Get this process's rank.

Returns	Current rank

template<typename T>
ClassHandle<T> comm::CommMPI::registerInstanceCollective(T* obj)

Parameters
obj	Pointer to the object to register
Returns	A handle for the registered instance

void comm::CommMPI::unregisterInstanceCollective(std::size_t idx)

Unregister a previously registered instance.

Parameters
idx	Index of the instance to unregister

void* comm::CommMPI::getInstanceCollective(std::size_t idx)

Get a registered instance by index.

Parameters
idx	Index of the instance
Returns	Pointer to the registered instance

template<auto fn, typename ProxyT, typename... Args>
void comm::CommMPI::send(int dest, ProxyT proxy, Args && ... args)

Send data to a destination rank.

Parameters
dest	Destination rank
proxy
args	Arguments to serialize and send
Exceptions
std::runtime_error	if destination rank is invalid

bool comm::CommMPI::poll()

Poll for incoming messages and process them.

Exceptions
Returns	true when termination occurs, false otherwise
std::runtime_error	if received message is invalid

Checks for new messages and processes them, also cleans up completed sends

template<typename T>
std::unordered_map<int, std::vector<T>> comm::CommMPI::allgather(T const* sendbuf, int sendcount)

Gather values from all ranks, with varying counts per rank, and remember per-rank contribution.

Template parameters
T	Type of the elements to gather (must be trivially copyable and one of the supported basic types)
Parameters
sendbuf	Pointer to the local data to send
sendcount	Number of elements to send from this rank
Returns	A map from rank -> vector of values contributed by that rank