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Functions
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.