[Scilab-users] Overflow convention for integer types

[Stéphane Mottelet]

Le 23/02/2018 à 15:50, Samuel Gougeon a écrit :
> Le 23/02/2018 à 14:06, Stéphane Mottelet a écrit :
>> Le 23/02/2018 à 13:45, Stéphane Mottelet a écrit :
>>> Hello,
>>>
>>> I would like to point out the conventions used by Scilab and Matlab 
>>> when an integer number is subject to overflow:
>>>
>>> Scilab 6.0.1:
>>>
>>> --> uint8(255)+1
>>>  ans  =
>>>
>>>   0
>>>
>>> Matlab R2017b
>>>
>>> >> uint8(255)+1
>>>
>>> ans =
>>>
>>>   uint8
>>>
>>>    255
>>>
>>> Do you see any reason in favor of one of each ?
>>>
>>> S.
>>>
>>>
>> Maybe monotonicity, but it should be discussed anyway.
>
> This has been already done here or/and on Bugzilla, quite extensively.
>
> Anyway, it can't be changed without breaking completely Scilab and 
> external modules.
> It is the same for 1.2 * int8(3) that yields an int8 and not a double.
>
> The fact that all these optimizations with a global impact were not 
> discussed and decided
> to prepare the 6.0.0 is indeed a HUGE pity.
> There are many ways to kill a software. Breaking things with a global 
> impact like this []+num again,
> and next minor release again, and next minor release again on another 
> point... is an excellent one.
>
> So, sorry, but this kind of (re)discussion and changes must be done 
> when targeting a major release
> for which all things must be rewritten.
> And decided and announced to all authors ASAP, not just 1 year before 
> the release.
>
> And since you put this on the table while the 6.0.1 is just released 
> and we had not the chance
> to read you here about that before looks rather strange to me.
No strangeness at all. I was just *asking* why Scilab's behavior is the 
one observed. No judgement at all, no claim. Because of a recent change 
in my professionnal position I have now enough time to spent a bit of it 
about Scilab (many years ago I spent *a lot* of time about it). Sorry 
for my "fresh" view of some facts that were discussed a long time ago, 
when I did not have time to read the mailing lists...

S.

>
> Best regards
> Samuel
>
> _______________________________________________
> users mailing list
> users at lists.scilab.org
> http://lists.scilab.org/mailman/listinfo/users


-- 
Stéphane Mottelet
Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
CS 60319, 60203 Compiègne cedex
Tel : +33(0)344234688
http://www.utc.fr/~mottelet