Hi Bill,
You were right, thanks!
Now I have:
int size = 5000;
double *matrix = (double *) R_alloc(size^2, sizeof(double));
Which works for larger sizes! But now I have discovered a new problem with it.
When I go to set the value of the elements it *sometimes* crashes:
for (i = 0; i < (size - 1); i++) {
for (j = i; j < (size - 1); j++) {
*(matrix + j*length + i) = 5;
}
}
About ever tenth time I run this code I get:
R(2535,0xa07f64e0) malloc: *** error for object 0x16830404: incorrect checksum
for freed object - object was probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug
Any idea why this is happening?
Thanks again!,
Erik
On Apr 10, 2010, at 5:35 PM, William Dunlap wrote:
>> -----Original Message-----
>> From: r-help-boun...@r-project.org
>> [mailto:r-help-boun...@r-project.org] On Behalf Of Erik Wright
>> Sent: Saturday, April 10, 2010 3:23 PM
>> To: r help
>> Subject: [R] .Call function crashes initializing matrix
>>
>> Hello,
>>
>> I have a C function that I call from R using .Call. I
>> recently discovered a bug in my code, and I am not sure if it
>> is a problem with what I am doing in C or if it has something
>> to do with my use of .Call.
>>
>> I have narrowed my problem down to these two C statements:
>> int size = 5000;
>> double matrix[size][size];
>>
>> When I run this in R it crashes, with this message:
>> *** caught segfault ***
>> address 0xb4141d70, cause 'memory not mapped'
>
> You may be overflowing the stack. Allocate
> the space for 'matrix' with the allocation
> functions described in section 5.9 of "Writing
> R Extensions". They allocate space on the 'heap',
> which has much more space than the stack (where
> space for 'automatic' variables is allocated).
> Typical stack sizes are on the order of few
> megabytes and typical heap sizes are in the gigabytes.
>
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com
>
>>
>> It has no problem when size is smaller, like 50. Any idea
>> what is going on?
>>
>> Thanks!,
>> Erik
>>
>>
>> sessionInfo()
>> R version 2.10.1 (2009-12-14)
>> i386-apple-darwin9.8.0
>>
>> locale:
>> [1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
>>
>> attached base packages:
>> [1] stats graphics grDevices utils datasets methods
>> [7] base
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
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