[Rcpp-devel] Vector allocation memory problem

[Dirk Eddelbuettel]

On 8 April 2011 at 09:12, Cedric Ginestet wrote:
| Hi guys,
| 
| I have encountered a reproducible error in using Rcpp, which I have reported
| below. Basically, while allocation of elements in a vector to a particular
| value works well for vectors of small sizes, this returns an error when the
| size of that vector is increased. Either it returns a giblc error or it hangs
| and never resumes. I have reproduced this error on two different Linux
| distributions (Ubuntu 10.10 and 10.04 with g++ 4.4.1 and R 2.12.1).
| 
| ####################################################
| library(Rcpp)
| library(inline)
| 
| src <- '
|   Rcpp::IntegerMatrix xA(A);
|   int n=xA.nrow();
|   NumericVector dist(n);
|   for(int i=0;i<=n;i++){dist[i]=1.0;}
|   return dist;'
| cxxfun <- cxxfunction(sig=signature(A="matrix"),body=src,plugin="Rcpp",verbose=
| TRUE)
| 
| ## Tests.
| n <- 20; A <- matrix(0,n,n); dist <- cxxfun(A);
| n <- 200; A <- matrix(0,n,n); dist <- cxxfun(A);
| n <- 2000; A <- matrix(0,n,n); dist <- cxxfun(A);
| *** glibc detected *** /usr/lib/R/bin/exec/R: double free or corruption (!
| prev): 0x08cfc278 ***
| 
| ####################################################
| 
| Is there something that I doing wrong there?

Yup, look like you found a bug. Even with small size (n=20, n=30, n=40)
I end up with the glibc error. Nasty. We'll take a look.

Dirk

| Thank you very much for your help,
| Ced
| 
| 
| --
| Cedric Ginestet
| Centre for Neuroimaging Sciences (L3.04)
| NIHR Biomedical Research Centre
| Institute of Psychiatry, Box P089
| Kings College London
| De Crespigny Park
| London
| SE5 8AF
| 
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-- 
Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com