basenetwork.h File Reference

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Description

Utility functions for basic MPI and network functionality.

Functions
bool	gmx_mpi_initialized ()
	Returns whether MPI has been initialized. More...
int	gmx_node_num ()
	Returns the number of nodes. More...
int	gmx_node_rank ()
	Returns the rank of the node. More...
int	gmx_physicalnode_id_hash ()
	Return a non-negative hash that is, hopefully, unique for each physical node. More...
void	gmx_broadcast_world (int size, void *buffer)
	Broadcasts given data from rank zero to all other ranks.
void	gmx_abort (int errorno)
	Abort the parallel run.

Function Documentation

bool gmx_mpi_initialized

(

)

Returns whether MPI has been initialized.

The return value is FALSE if MPI_Init() has not been called, or if GROMACS has been compiled without MPI support. For thread-MPI, returns TRUE when the threads have been started.

Note that there is a lot of code in between MPI_Init() and the thread-MPI thread start where the return value is different depending on compilation options.

int gmx_node_num

(

)

Returns the number of nodes.

For thread-MPI, returns one before the threads have been started. This allows code between the real MPI_Init() and the thread-MPI "init" to still use this function to check for serial/parallel status and work as expected: for thread-MPI, at that point they should behave as if the run was serial.

int gmx_node_rank

(

)

Returns the rank of the node.

For thread-MPI, returns zero before the threads have been started. This allows code between the real MPI_Init() and the thread-MPI "init" to still use this function to check for master node work as expected: for thread-MPI, at that point the only thread of execution should behave as if it the master node.

int gmx_physicalnode_id_hash

(

)

Return a non-negative hash that is, hopefully, unique for each physical node.

This hash is useful for determining hardware locality.