I getting "Error in matrix(0, n, n) : too many elements specified"
while building randomForest model, which looks like memory allocation
error.
Software versions are: randomForest 4.5-25, R version 2.7.1

Dataset is big (~90K rows, ~200 columns), but this is on a big machine (
~120G RAM)
and I call randomForest like this: randomForest(x,y)
i.e. in supervised mode and not requesting proximity matrix, therefore
answer from Andy Liaw to an email reporting the same problems in 2005
(see below)
is probably not directly applicable, still it looks like it is too big
data set for this dataset/machine combination.

How does memory usage in randomForest scale with dataset size?
Is there a way to build global rf model with dataset of this size?

Best regards,
Ryszard

Ryszard Czerminski
AstraZeneca Pharmaceuticals LP
35 Gatehouse Drive
Waltham, MA 02451
USA
781-839-4304
ryszard.czerminski@astrazeneca.com

RE: [R] randomForest: too many element specified?
Liaw, Andy
Mon, 17 Jan 2005 05:56:28 -0800
> From: luk
>
> When I run randonForest with a 169453x5 matrix, I got the
> following message.
>
> Error in matrix(0, n, n) : matrix: too many elements specified
>
> Can you please advise me how to solve this problem?
>
> Thanks,
>
> Lu

1.  When asking new questions, please don't reply to other posts.

2.  When asking questions like these, please do show the commands you
used.

My guess is that you asked for the proximity matrix, or is running
unsupervised randomForest (by not providing a response vector).  This
will
requires a couple of n by n matrices to be created (on top of other
things),
n being 169453 in this case.  To store a 169453 x 169453 matrix in
double
precision, you need 169453^2 * 8 bytes, or or nearly 214 GB of memory.
Even
if you have that kind of hardware, I doubt you'll be able to make much
sense
out of the result.

Andy



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