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

[Horand Gassmann]

Kipp Martin <kmartin at chicagobooth.edu> wrote:

> Hi Jun:
>
>
>> It may help to think  an optimization like this:
>> maximize 1/0
>> subject to ......
>
> How would you input 1/0 into a solver?
>
> I suppose you could do something like
>
> max x/y
>
> where x is constrained to be 1 and y constrained to 0.  I wonder how
> many solvers would return a NaN?

I`m from Missouri, sometimes, and I am a firm believer in KISS (the  
principle, not the rock band :^) ), so I tried the following:

<nonlinearExpressions numberOfNonlinearExpressions="1">
	<nl idx="-1">
		<divide>
			<number type="real" value="1.0 "/>
			<number type="real" value="0.0 "/>
		</divide>
	</nl   >
</nonlinearExpressions>

Here is the output:

./OSSolverService -osil ../OS/data/osilFiles/NaNTest.osil -solver ipopt

Optimization Services Solver
Main Authors: Horand Gassmann, Jun Ma, and Kipp Martin
Distributed under the Eclipse Public License
OS Version: trunk
Build Date: Feb  1 2011
SVN Version: 4041


******************************************************************************
This program contains Ipopt, a library for large-scale nonlinear optimization.
  Ipopt is released as open source code under the Eclipse Public License (EPL).
          For more information visit http://projects.coin-or.org/Ipopt
******************************************************************************

NOTE: You are using Ipopt by default with the MUMPS linear solver.
       Other linear solvers might be more efficient (see Ipopt documentation).

Segmentation fault


Haven't figured out yet where this comes from, but we obviously manage  
to start Ipopt before it bombs. Is this something for Andreas?

Cheers

gus