Hi Jay,

Thanks for the reply:)

Could you show me a link of the c++ examples? Thank you very much.

ya




ya

From: Jay Emerson
Date: 2012-05-11 20:12
To: xinxi813
CC: r-help
Subject: Re: bigmemory
R internally uses 32-bit integers for indexing (though this may change).  For this and other reasons these external objects with specialized purposes (larger-than-RAM, shared memory) simply can't behave exactly as R objects.  Best case, some R functions will work.  Others would simply break.  Others would perhaps work if the problem is small enough, but would choke in the creation of temporary objects in memory.

I understand your sentiment, but it isn't that easy.  If you are interested, however, we do provide examples of authoring functions in C++ which can work interchangeably on both matrix and big.matrix objects.  

Jay


Hi Jay,

I have a question about your reply.

You mentioned that "the more serious problem is that you can't expect to run just any R function on a big.matrix (or on an ff object, if you check out ff for some nice features).  " 

I am confused why the packages could not communicate with each other. I understand that maybe for some programming or statistical reasons, one package need its own "class" so that specific algorithm can be implemented. However, R as a statistical programming environment, one of its advantages is the abundance of the packages under R structure. If different packages generate different kinds of object and can not be recognized and used for further analysis by other packages, then each package would appears to be similar with the normal independent software, e.g., SAS, MATLAB... then this could reduce the whole R ability for handling complicated analysis situation.

This is just a general thought.

Thank you very much.




ya


-- 
John W. Emerson (Jay)
Associate Professor of Statistics
Department of Statistics
Yale University
http://www.stat.yale.edu/~jay
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