mpid_put_sametype.tex

来自「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」· TEX 代码 · 共 56 行

\startmanpage
\mantitle{MPID{\tt \char`\_}Put{\tt \char`\_}sametype}{tex}{10/7/2002}
\manname{MPID{\tt \char`\_}Put{\tt \char`\_}sametype}
--- Implement a put operation where the source and  destination datatypes are (roughly) the same 
\subhead{Synopsis}
\startvb\begin{verbatim}
int MPID_Put_sametype( const void *origin_buf, int n, MPID_Datatype *dtype,
                      MPI_Aint target_offset, int target_rank, MPID_Comm *comm,
                      volatile int *local_flag, MPI_Aint target_flag )

\end{verbatim}
\endvb

\startarg{buf }{Pointer to local memory to be copied
}
\startarg{n   }{Count of datatype to move
}
\startarg{dtype }{Datatype describing both the source and destination datatype. 
See notes.
}
\startarg{target{\tt \char`\_}offset }{Location of destination 
}
\startarg{target{\tt \char`\_}rank }{Rank of the destination process in the communicator
}
\startarg{comm }{Communicator
}
\startarg{local{\tt \char`\_}flag }{Address of a flag to be set when this call is locally complete.
}
\startarg{target{\tt \char`\_}flag }{This is an id of a flag at the target process.  This value
must have been specified by the target process in a previous communication
(either with {\tt MPID{\tt \char`\_}Put{\tt \char`\_}contig} or {\tt MPID{\tt \char`\_}Rhcv}).  A value of {\tt 0} indicates no
target completion flag.
Notes:
This routine allows the efficient implementation of strided copies, where
both the origin and the target have the same strides.  
}
\par
\subhead{Question}
We may want to generalize this to two related types, where there are
only a few differences between the datatypes.  For example, both are
strided types, but with different strides.  Or both are indexed types, but
with different offset arrays.  This does not support the general case,
but it does support an important special case, such as the halo exchange
operation, without requiring an intermediate contiguous buffer.
\par
We may also want to restrict this to strided types, instead of sametype.
My reason for picking sametype is that this allows slighly more complex
datatypes, such as a 2-d face of a 3-d cube.
\par
Do we want {\tt Put{\tt \char`\_}contig{\tt \char`\_}to{\tt \char`\_}general} and {\tt Put{\tt \char`\_}general{\tt \char`\_}to{\tt \char`\_}contig} so we can
implement the general case?
\par
\subhead{Module}
Communication
\endmanpage