Thanks a lot for your answer :)
actually I am converting a 256*256 image to a vector so to apply some 1-d transformations. Is it possible to  create in R a sparse matrix instead of carrying all those zeros? 

So that means that I want to have a diagonal sparse matrix..

Thanks a lot 

Alex


________________________________
 From: peter dalgaard <pdalgd@gmail.com>

Cc: "R-help@r-project.org" <R-help@r-project.org> 
Sent: Monday, February 6, 2012 11:54 AM
Subject: Re: [R] R's memory capabilities


On Feb 6, 2012, at 11:15 , Alaios wrote:

> Dear all,
> I have tried to create a diagonal matrix of size diag(65536)
> 
> I am getting the message that the array function can not create so big array as the value I ask is larger than the
> 
> 
> <environment: namespace:base>
>> .Machine$integer
> [1] 2147483647
> 
> 
> as you will see my .Machine$integer is the one above. What that variable means? I am using R in a system that has 500 GB of ram available. Would it be something wrong in the installation?

Well, it means what it says. Indexing is limited by the size of a 32-bit integer and (2^16)^2 is too big for that. So you are limited to roughly 16 GB for any single object in R. 

This issue has been foreseeable for some time. It can only be fixed by internal changes in the R engine, but switching to long integers has various issues, so it is not a straightforward modification.

Meanwhile, you might want to consider whether you really do need a diagonal matrix of that size stored in full. It's an awful lot of zeroes to carry around....

> 
> Regards
> Alex
> 
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> 
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-- 
Peter Dalgaard, Professor
Center for Statistics, Copenhagen Business School
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Phone: (+45)38153501
Email: pd.mes@cbs.dk  Priv: PDalgd@gmail.com
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