Takes either an R matrix and distributes it as a distributed matrix, or takes a distributed matrix and redistributes it across a (possibly) new BLACS context, using a (possibly) new blocking dimension.
reblock(dx, bldim = dx@bldim, ICTXT = .pbd_env$ICTXT)redistribute(dx, bldim = dx@bldim, ICTXT = .pbd_env$ICTXT)
numeric distributed matrix
the blocking dimension for block-cyclically distributing the matrix across the process grid.
BLACS context number for return.
Returns a distributed matrix.
distribute() takes an R matrix x stored on the processes in
some fashion and distributes it across the process grid belonging to
ICTXT. If a process is to call distribute() and does not yet
have any ownership of the matrix x, then that process should store
NULL for x.
How one might typically use this is to read in a non-distributed matrix on
the first process, store that result as the R matrix x, and then have
the other processes store NULL for x. Then calling
distribute() returns the distributed matrix which was distributed
according to the options bldim and ICTXT.
Using an ICTXT value other than zero is not recommended unless you
have a good reason to. Use of other such contexts should only be considered
for advanced users, preferably those with knowledge of ScaLAPACK.
redistribute() takes a distributed matrix and redistributes it to the
(possibly) new process grid with BLACS context ICTXT and with the
(possibly) new blocking dimension bldim. The original BLACS context
is dx@ICTXT and the original blocking dimension is dx@bldim.
These two functions are essentially simple wrappers for the ScaLAPACK
function PDGEMR2D, with the above described behavior. Of note, for
distribute(), dx@ICTXT and ICTXT must share at least one
process in common. Likewise for redistribute() with xCTXT and
ICTXT.
Very general redistributions can be done with redistribute(), but
thinking in these terms is an acquired skill. For this reason, several
simple interfaces to this function have been written.