Re: [boost] [Boost-users] [Review] ITL review starts today, February 18th

Subject: Re: [boost] [Boost-users] [Review] ITL review starts today, February 18th
From: Joachim Faulhaber (afojgo_at_[hidden])
Date: 2010-03-04 12:13:51

2010/3/4 John Reid <j.reid_at_[hidden]>:
> John Reid wrote:
>>
>>
>> Joachim Faulhaber wrote:
>>>>
>>>> So it might be better to have
>>>> both continuous and discrete intervals as right-open by default and to
>>>> allow
>>>> some mechanism whereby the user can choose to allow different runtime
>>>> bound
>>>> types if they need them.
>>>
>>> I agree, that right-open intervals are suitable as default. But I am
>>> afraid, for the continuous case, we can not guarantee that all
>>> operations can maintain such an invariant. BTW existing interval
>>> libraries e.g. boost::numeric::interval or FILIB++ work with closed
>>> intervals. Subtract a closed interval from an interval set with
>>> continuous domain_type  and you need open bounds.
>>
>> I was suggesting that your design could feature sets/maps that only had
>> right-open intervals. This would be the default in both continuous and
>> discrete domains. If the user really wanted to use all the different
>> interval bound types over a continuous domain then perhaps he/she could
>> choose to do so via a template parameter. This would probably be a rare use
>> case though.
>>
>
> I should just say that I think all the invariants can be maintained in sets
> of right-open intervals. Please correct me if I'm wrong.

I think it can be maintained for intervals of integral domain_types
but it can not be maintained for intervals of continuous domain_types.
To be more accurate: I have my doubts if it can be maintained and to
be even more precise: I don't know if it can be maintained in this
case, without loss of generality or correctness of the implementation.

For discrete domain_type at least, I am prepared to provide it.

Joachim.