On Sun, Jul 19, 2009 at 2:29 PM, Jay Emersonjayemer...@gmail.com wrote:
Hi Jay!
foreach(i=1:nrow(x),.combine=c) %dopar% f(x[i,])
That was also my first guess, but it doesn't seem to work. Here is a
trivial example using a regular matrix instead of a big.matrix. The
outcome is the same.
m =
On Sun, Jul 19, 2009 at 4:02 PM, Michael Kanekaneplusp...@gmail.com wrote:
Hi Mike,
desc = describe(x)
foreach (i=1:nrow(x), .combine=c, .packages='bigmemory') %dopar%
{
x = attach.big.matrix(desc)
f(x[i,])
}
Thanks! The shared.big.matrix was exactly what I needed. It still
remains
On Mon, Jul 20, 2009 at 10:23 AM, Michael Knudsenmicknud...@gmail.com wrote:
Thanks! The shared.big.matrix was exactly what I needed. It still
remains for me, though, to check if I run into memory problems anyway.
It doesn't seem as if there's a don't return anything option in the
foreach
Michael,
If you have a big.matrix, you just want to iterate over the rows. I'm not
in R and am just making this up on the fly (from a bar in Beijing, if you
believe that):
foreach(i=1:nrow(x),.combine=c) %dopar% f(x[i,])
should work, essentially applying the functin f() to the rows of x? But
Another thing to realize if you are doing this in parallel, f(x[i,]) is
being executed on each of the worker R sessions. Now, a big.matrix object
is essentially a pointer to an object created in C++ and, a pointer address
space is specific to a process (in this case the master R session). As a
Hi there!
I have become a big fan of the 'foreach' package allowing me to do a
lot of stuff in parallel. For example, evaluating the function f on
all elements in a vector x is easily accomplished:
foreach(i=1:length(x),.combine=c) %dopar% f(x[i])
Here the .combine=c option tells foreach to
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