[R] Problem with C extension
ripley at stats.ox.ac.uk
Mon Jan 22 18:06:12 CET 2007
On Mon, 22 Jan 2007, Markus Schmidberger wrote:
> thanks for help and code.
> We did a lot of work to speedup our function in R. We have a nested loop,
> vectorizing is the fastest way. But there we got a very big matrix and
> problems with memory. So we want to stay by loops an speedup with C.
> My code is similar to this. (my_c is code from Brian D. Ripley)
And not in many ways similar to mine, hence your error message.
You really do have to handle all the types, as I did most.
> SEXP test(SEXP a, SEXP b, SEXP in)
> SEXP ans, new;
> int n=INTEGER(in),i,j;
> PROTECT(ans = allocVector(REALSXP, 1));
> /* for(j = 0; i < m; j++)*/
> for(i = 0; i < n; i++)
> /* b= ... ^i ....*j*/
> PROTECT(new = allocVector(REALSXP, i+2));
> new = my_c(ans,b);
> PROTECT(ans = allocVector(REALSXP, i+2));
> ans = new;
> return ans;
> We get an error by in=1300
> Fehler: type mismatch
> Is there a possibility to free allocated memory? free(...) does not work.
No, but garbage collection does.
> Is there a possibility to reallocate a vector?
Yes, sort of. See lengthgets().
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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