[Rcpp-devel] Vector allocation memory problem

[Cedric Ginestet]

Thanks guys,

This is partly why I got confused with this basic mistake. Why don't I 
get a glibc error for all sizes of the vector on my distribution? Shall 
I try to change the default of my g++ compiler or update to a different 
version?

Remember, I am currently using Ubuntu 10.04 with g++ 4.4.1 and R 2.12.1.
Cheers,

Cedric



On 08/04/11 13:36, Dirk Eddelbuettel wrote:
> 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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