[Os-project-managers] Fork in the Road

[Kipp Martin]

Hi Gus:

>
> Let me add another thought. This whole discussion has been extremely
> stimulating, and it has made me realize that there is a fundamental
> difference between input and output methods as far as encapsulation is
> concerned. We do not have the same problem with the OSoL format, because
> we can always pass the entire OSoL file down the line. The server reads
> its pieces, but it does not have to "decapsulate" the parts that need to
> go to the server. You pay the price of a bit of redundancy, because what
> the server passes to the solver has information we know to be useless,
> but that is trivial. It's the return path that is hard.

Aha! You say:  "You pay the price of a bit of redundancy, because what
the server passes to the solver has information we know to be useless,
but that is trivial."

Then solver writers need to know what is useless, i.e. what they should 
and should not try to read. If I am a solver developer I would assume 
that I should be processing ALL of the OSoL file. I am pretty irritated 
if I get useless information. This is what I keep coming back to: OSoL 
should only contain information relevant to the solver and OSrL should 
only be information coming back from the solver. We had things correct 
with version 1.0 and then really screwed up in going to 2.0. Indeed, I 
would favor a modification to your previous option 4 in that when we do 
a remote_solve()  we package the OSoL inside OSpL, then strip out the 
OSoL and send it to the solver. Having OSpL information inside OSrL and 
OSoL is fundamentally wrong in my opinion.

My Mantra: "OSoL should only contain information relevant to the solver 
and OSrL should only be information coming back from the solver."

Cheers




-- 
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

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