mpid_segment_init_pack.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`\_}Segment{\tt \char`\_}init{\tt \char`\_}pack}{tex}{10/7/2002}
\manname{MPID{\tt \char`\_}Segment{\tt \char`\_}init{\tt \char`\_}pack}
--- Get a segment ready for packing and sending (put, Rhcv, and/or stream) data 
\subhead{Synopsis}
\startvb\begin{verbatim}
int MPID_Segment_init_pack( const void *buf, int count, MPID_Datatype *dtype,
                            MPID_Comm *comm, int rank, 
                            MPID_Segment *segment )

\end{verbatim}
\endvb

\subhead{Input Parameters}
\startarg{buf   }{Buffer to setup for sending
}
\startarg{count }{Number of items
}
\startarg{dtype }{Datatype of items
}
\startarg{comm  }{Communicator for communication
}
\startarg{rank  }{Rank of target.  Use {\tt MPI{\tt \char`\_}ANY{\tt \char`\_}SOURCE} for any member of the 
communicator
}
\par
\subhead{Output Parameter}
\startarg{segment }{Segment descriptor.  
}
\par
\subhead{Notes}
Initializes a {\tt MPID{\tt \char`\_}Segment} from a specified user buffer which is
described by {\tt (buf,count,datatype)} and hence may represent noncontiguous
data or contiguous data in a heterogeneous system.
\par
\subhead{Module}
Segment
\par
\subhead{Questions}
Add an {\em intent} so that sending all of the data can use device
knowledge about complex data layouts?  E.g., {\tt intent $=$$=$ MPID{\tt \char`\_}BUFFER{\tt \char`\_}ALL
}or {\tt intent $=$$=$ MPID{\tt \char`\_}BUFFER{\tt \char`\_}SEGMENT}?
\par
The original description contained this text:
\par
If null, the original buffer is contiguous and can be used as is.
\par
If {\tt buf{\tt \char`\_}desc} is non-null, the routine {\tt MPID{\tt \char`\_}Segment{\tt \char`\_}pack} must be used
to fill a memory location or return a pointer to a contiguous buffer.
\par
However, the code is somewhat simplified if a segment is always used
(in an case where a segment {\em may} be used).
\par
\endmanpage