[Os-project-managers] NaN in xs:double (OSrL)

[Kipp Martin]

Hi Gus:

It seems to me that by definition of an optimal, indeed even feasible 
solution, cannot contain a NaN.  If the solver does return NaN my first 
inclination is in the <optimization> child <status> set type = "error" 
and under description say "solver returned a NaN."  In  such a case we 
would not print a <solution>. I would argue that having a NaN as a 
solution value is an oxymoron.

Cheers


>
> as we saw a couple of days ago, NaN is a legal value for initial
> variable values. What about returning NaN from the solver? I don`t
> think I can currently say
>
> <solution ...>
> 	<variables ...>
> 		<values numberOfVar="2">
> 			<var idx="0">NaN</var>
> 			<var idx="1"/>
> 		</values>
> ...
>
> Both of the<var>  lines will give an error, and I am a bit uneasy
> about interpreting the second one as NaN. But it seems useful to me to
> have a solver return NaN in case there are problems (such as taking
> the square root of a negative number). Any ideas? Do we need to expand
> the definition of xs:double?
>
> 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