[Rd] R_alloc with more than 2GB (PR#7721)
huber at ebi.ac.uk
Thu Mar 10 23:36:37 CET 2005
Dear Prof Ripley,
> It is a feature. Other parts of R expect a CHARSXP to have length less
> than or equal to 2^31 - 1.
OK, after looking closer at the code and comments in memory.c and
Rinternals.h (typedef int R_len_t;) I realized that.
> Could you not use x = allocVector(REALSXP, vs) and REAL(x)[i]? That
> will get you up to 2^31 - 1 elements, which is the R limit AFAIK.
Thanks, that is an excellent idea. It should be fine for my immediate
needs, and better what I've just been doing with Calloc!
> Because of the use of Fortran, it is hard to see how to allow internal
> lengths (in elements, not necessarily bytes) to exceed that value. We
> need to return to that, but it is not straightforward and last time we
> discussed it we agreed to defer it.
> We can manage a better error message, but I am afraid nothing else in
> the near future.
In the application that triggered this posting, the memory is for a C
array of doubles within a user-defined C function, not for anything that
needs to become an R object, so maybe a suggestion would be to make
R_alloc go directly to malloc without the detour over allocString or
allocVector; or something along that line?
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