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<H3><A NAME="SECTION04853100000000000000">Purpose</A></H3>
<P>
PxTRMR2D copies the indicated (sub)matrix of A to the indicated
(sub)matrix of B. A and B can have arbitrary block-cyclic
distributions: they can be distributed across different process
grids, have different blocking factors, etc.
<P>
The (sub)matrix to be copied is assumed to be trapezoidal. So only
the upper or the lower part will be copied. The other part is
unchanged.
<P>
Particular care must be taken when the process grid over which matrix A
is distributed (call this context A) is disjoint from the
process grid over which matrix B is distributed (call this context B).
The general rules for which parameters need to be set are as follows:
<P>
<UL>
<LI>
All calling processes must have the correct M and N.
<LI>
Processes in context A must correctly define all parameters describing A.
<LI>
Processes in context B must correctly define all parameters describing B.
<LI>
Processes that are not members of context A must pass DESCA(CTXT_) = -1
and need not set other parameters describing A.
<LI>
Processes that are not members of context B must pass DESCB(CTXT_) = -1
and need not set other parameters describing B.
</UL><BR> <HR>
<P><ADDRESS>
<I>Susan Blackford <BR>
Tue May 13 09:21:01 EDT 1997</I>
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