[Os-project-managers] [Fwd: OSoL, OSrL, change sets 2819 and 3013]

[Kipp Martin]

Hi Gus:
> 
> Ah, this is not quite accurate. In OSoL and OSrL we have an  
> <optimization> element with attributes "numberOfVariables",  
> "numberOfObjectives" and "numberOfConstraints". These attributes are  
> redundant and do not have an equivalent in OSiL. Whenever we do need  
> the number of items in an element, such as number of variables in the  
> OSoL element <initialVariableValues>, we require /in this element/ a  
> mandatory attribute "numberOfVariables". I have no plans to abandon  
> that. However, the attribute "numberOfVariables" in the parent element  
> 'optimization. is not used for anything (other than perhaps a  
> consistency check, namely that each "idx" in the  
> <initialVariableValues> has a legal value (between 0 and  
> "numberOfVariables"). In OSoL the attribute is entirely unnecessary  
> and may actually stand in the way of reusability, and in OSrL it does  
> not add much of value either.
> 
> To be specific, I am talking about removing the attribute  
> "numberOfVariables" in line 195 of OSoL.xsd, *not* the attribute  
> "numberOfVar" in line 241.

Aha, mea culpa. Now I understand. Yes, I very clearly see the 
difference. And yes, I agree they SHOULD NOT be required. Indeed, I now 
remember in the OSoL debate the argument that carried the day was that 
in OSoL the file might actually be for multiple solvers and multiple 
problem instances.

Cheers
> 
> 
> 
>> I prefer we instead make OSoL required. Here is my logic. If we use
>> optional instead of required we impose a tax on people who want to use a
>> language such as C for implementation. In C there is no vector
>> construct. So if you don't know numberOfXXX this is a big problem. What
>> is the logic of imposing this tax on developers?
> 
> See above. The particular information I want to remove is actually redundant.
> 
> Cheers
> 
> gus
> 
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-- 
Kipp Martin
Professor of Operations Research
and Computing Technology
Booth School of Business
University of Chicago
5807 South Woodlawn Avenue
Chicago, IL 60637
773-702-7456
kmartin at chicagobooth.edu
http://www.chicagobooth.edu/faculty/bio.aspx?person_id=12825325568
http://projects.coin-or.org/OS