[Os-project-managers] A modest proposal

[Horand Gassmann]

"R. Kipp Martin" <kmartin at chicagobooth.edu> wrote:

> Hi Guys:
>
> Here is one possible approach:
>
> 1) I do not favor an OSAmpl2OSxL. I prefer to keep separate classes.  
> OSnl2osil and OSnl2osol. I am not bothered by reading an nl file  
> twice.
>
> 2) Write an OSnl2osol class. This class would do the following:
>
> a) have a method readOSoL that would read an existing OSoL file and  
> create an OSOption object. If no such file exists, we simply new an  
> OSoL file with nothing.

You mean we new an OSOption object, correct?

> b) Read the nl file.
>
> c) I think we initially support a predetermined set of suffixes. We  
> get these suffixes using ASL. We first (order does not matter) get  
> the suffixes we support associated with variables and write a method  
> to put these in the existing OSoL file in the correct location. We  
> can do this since we know the suffix. Then follow with rows and then  
> the objective function.

This is certainly workable, it is reasonably easy, and it is fairly  
obvious what we should look for: .init, .status and .priority. Those  
are the three suffixes most likely supported by solvers, and they are  
the suffixes most likely to be used by users. We can also go through  
the AMPL interfaces of other COIN-OR projects to see what suffixes  
they currently support.

> Doing 2 above would greatly increase our AMPL functionality.

Agreed.

Cheers

gus