mpid_topo_cluster_info.tex

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

\startmanpage
\mantitle{MPID{\tt \char`\_}Topo{\tt \char`\_}cluster{\tt \char`\_}info}{tex}{10/7/2002}
\manname{MPID{\tt \char`\_}Topo{\tt \char`\_}cluster{\tt \char`\_}info}
--- Return information on the hierarchy of  interconnections 
\subhead{Synopsis}
\startvb\begin{verbatim}
int MPID_Topo_cluster_info( MPID_Comm *comm, 
                          int *levels, int my_cluster[], int my_rank[] )

\end{verbatim}
\endvb

\subhead{Input Parameter}
\startarg{comm }{Communicator to study.  May be {\tt NULL}, in which case {\tt MPI{\tt \char`\_}COMM{\tt \char`\_}WORLD
}is the effective communicator.
}
\par
\subhead{Output Parameters}
\startarg{levels }{The number of levels in the hierarchy.  
To simplify the use of this routine, the maximum value is 
{\tt MPID{\tt \char`\_}TOPO{\tt \char`\_}CLUSTER{\tt \char`\_}MAX{\tt \char`\_}LEVELS} (typically 8 or less).
}
\startarg{my{\tt \char`\_}cluster }{For each level, the id of the cluster that the calling process
belongs to.
}
\startarg{my{\tt \char`\_}rank }{For each level, the rank of the calling process in its cluster
}
\par
\subhead{Notes}
This routine returns a description of the system in terms of nested
clusters of processes.  Levels are numbered from zero.  At each level,
each process may belong to no more than cluster; if a process is in any
cluster at level i, it must be in some cluster at level i-1.
\par
The communicator argument allows this routine to be used in the dynamic
process case (i.e., with communicators that are created after {\tt MPI{\tt \char`\_}Init
}and that involve processes that are not part of {\tt MPI{\tt \char`\_}COMM{\tt \char`\_}WORLD}).
\par
For non-hierarchical systems, this routine simply returns a single
level containing all processes.
\par
\subhead{Sample Outputs}
For a single, switch-connected cluster or a uniform-memory-access (UMA)
symmetric multiprocessor (SMP), the return values could be
\begin{verbatim}
    level       my_cluster         my_rank
    0           0                  rank in comm_world
\end{verbatim}

This is also a valid response for {\em any} device.
\par
For a switch-connected cluster of 2 processor SMPs
\begin{verbatim}
    level       my_cluster         my_rank
    0           0                  rank in comm_world
    1           0 to p/2           0 or 1
\end{verbatim}

where the value each process on the same SMP has the same value for
{\tt my{\tt \char`\_}cluster[1]} and a different value for {\tt my{\tt \char`\_}rank[1]}.
\par
For two SMPs connected by a network,
\begin{verbatim}
    level       my_cluster         my_rank
    0           0                  rank in comm_world
    1           0 or 1             0 to # on SMP
\end{verbatim}

\par
An example with more than 2 levels is a collection of clusters, each with
SMP nodes.
\par
\subhead{Limitations}
This approach does not provide a representations for topologies that
are not hierarchical.  For example, a mesh interconnect is a single-level
cluster in this view.
\par
\subhead{Module}
Topology
\endmanpage