Hi all,

I was trying a probit regression using polr() and got this message,

Error in model.matrix.default(Terms, m, contrasts) :
        cannot allocate vector of length 828310236

The data is about 20M (a few days ago I asked a question about large file,
thank you for responses, then I use MS Access to select those columns I
would use).

R is 2.3.1, Windows XP, 512M Ram.

I am going to read some help on memory use in R, but hope anybody can give
me some quick hints.

Is it because iphysical memory runs out, or some other things could be wrong
with data or polr()?
Does R use virtual memory? If so, what options can I set?
If not, can R deal with really huge data (except adding RAM according to
data size)? If this is the case, it is too bad that I have to tell my boss
to go back to SAS. Now it is not a speed issue yet.

Thank you.

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