[gecode-users] int vs. unsigned int for Matrix dimensions

[Gregory Crosswhite]

Part of the reason I am asking how to talk to the developers, 
by-the-way, is because I was thinking it might be useful for the 
arrays/argument arrays to have an iterator interface added to them, to 
make it easier to do things like applying generics algorithms to them 
and traversing them using the c++0x "for each" statement as well as 
BOOST_FOREACH.  Would there be any interest in a contribution to Gecode 
to provide this?  The supporting code that I had in mind would include 
new classes for the iterators and new methods .begin() and .end() for 
the arrays.

Cheers,
Greg

On 1/16/11 1:46 PM, Gregory Crosswhite wrote:
> Okidoke;  thanks for the explanation!  :-)
>
> Also, is this list the best way to talk to the developers of Gecode?
>
> Thanks,
> Greg
>
> On 1/16/11 1:10 PM, Christian Schulte wrote:
>> Hi Gregory,
>>
>> You are touching a slightly weird aspect of Gecode... The choice of 
>> int as
>> opposed to unsigned int for the Matrix class is actually deliberate. 
>> This
>> choice is not only done for Matrix but for many other datastructures 
>> that
>> are defined by Gecode (for example, VarArray, ViewArray, etc). I know 
>> that
>> the choice of unsigned int sounds more appealing but we have made the
>> opposite decision and try to be as consistent with the choice of int 
>> rather
>> than unsigned int.
>>
>> There are two reasons. The first is simple and maybe is not even very
>> convincing. The average loop written to iterate over arrays etc is 
>> typically
>> an int and not an unsigned int. To avoid compiler warnings, Gecode 
>> follows
>> in this. Then, the second reason (possibly not more convincing than the
>> first one) is that integer variables take int values and very often 
>> array
>> access is wrt a value included in the domain of an integer variable. 
>> Here we
>> go.
>>
>> We tried to use unsigned int but it was in fact just too painful 
>> (lots of
>> explicit casts in order to avoid warnings). Changing int to unsigned 
>> int and
>> be consistent about that change would be a massive effort with little 
>> gain.
>>
>> I know. Sad but true.
>>
>> Cheers
>> Christian
>>
>> -- 
>> Christian Schulte, web.ict.kth.se/~cschulte/
>>
>>
>> -----Original Message-----
>> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On 
>> Behalf
>> Of Gregory Crosswhite
>> Sent: Friday, January 14, 2011 6:26 PM
>> To: users at gecode.org
>> Subject: [gecode-users] int vs. unsigned int for Matrix dimensions
>>
>> Hey everyone,
>>
>> Is there a reason why the Matrix class uses "int" for the type of its
>> dimensions instead of "unsigned int"?  If there isn't a reason not to
>> use "unsigned int" for the type of the dimensions, then may I submit a
>> patch or something to change it to use "unsigned int"?
>>
>> Thanks!
>> Greg
>>
>> _______________________________________________
>> Gecode users mailing list
>> users at gecode.org
>> https://www.gecode.org/mailman/listinfo/gecode-users
>>
>
>
> _______________________________________________
> Gecode users mailing list
> users at gecode.org
> https://www.gecode.org/mailman/listinfo/gecode-users