[gecode-users] Bug in TupleSet?

[Malcolm Ryan]

Why not just make adding the duplicate elements to be without effect?
That's what most set implementations I've encountered do.

Malcolm

On 03/12/2008, at 5:37 PM, Mikael Zayenz Lagerkvist wrote:

> A TupleSet does not accept more than one instance of a tuple (hence
> the name set). However, the implementation should probably be safer
> for erroneous usage and throw an exception during finalization if
> multiple tuples are discovered.
>
> Cheers,
> Mikael
>
> On Tue, Dec 2, 2008 at 12:58 AM, Malcolm Ryan <malcolmr at cse.unsw.edu.au 
> > wrote:
>> There seems to be a bug in TupleSet. If you add a particular tuple
>> more than twice, the next call to extensional will segfault. Eg:
>>
>>       TupleSet tuples;
>>
>>       int n = 3;              // works if n <= 2
>>
>>       for (int i = 0; i < n; i++) {
>>               IntArgs pair(2);
>>               pair[0] = 0;
>>               pair[1] = 1;
>>
>>               tuples.add(pair);
>>       }
>>
>>       TestSpace* space = new TestSpace();
>>
>>       IntVarArray x(space, 2, 0, 1);
>>       space->add(x);
>>
>>       extensional(space, x, tuples);  // segfault if n >= 3
>>
>> (where TestSpace is a simple Space implementation)
>>
>> GDB shows:
>>
>> Program received signal EXC_BAD_ACCESS, Could not access memory.
>> Reason: KERN_PROTECTION_FAILURE at address: 0x00000000
>> 0x0057f857 in (anonymous namespace)::FullTupleCompare::operator() ()
>> at gecode/int/extensional/tuple-set.cc:55
>> 55              if (a[i] < b[i]) {
>>
>> Malcolm
>>
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>>
>
>
>
> -- 
> Mikael Zayenz Lagerkvist, http://www.ict.kth.se/~zayenz/