[Symphony] Symphony and AMPL in a Dockerfile

[Ted Ralphs]

Hi Patrick,

First, thanks for taking the time to make the Docker image. I've meant to
make the effort to learn a bit about Docker and this gives me a way to dive
in. As a side comment, the documentation you are referring to is for a
different version than you're using, though this is not the reason you're
having trouble.

Looking at the commands in your docker file, they are exactly correct as
far as I can see. I can try to replicate everything here locally, but on
the face of it, I really don't see why you're getting the error. If it
would be easy to send me the config.log file from the SYMPHONY subdirectory
and perhaps even the output from the script off-line, I could probably spot
the trouble. Perhaps the get.Glpk script is failing but not returning an
error code so that the build still goes through? I have had trouble running
that script on some platforms due to github certificate issues. I will try
to replicate your steps and see what I can find out.

As an aside, depending on what you're really trying to do, I may be able to
recommend better options for using SYMPHONY (and/or other open source
solvers) with AMPL. Reading the AMPL model directly with SYMPHONY has some
shortcomings when it comes to getting solutions back out and doing
post-solution analysis. There are a number of other options, such as
building the AMPL client included in the Optimization Services project (
projects.coin-or.org/OS), which wraps SYMPHONY and a number of other
solvers and can be called from AMPL in the standard way.

Building OS is exactly like building SYMPHONY. To build the AMPL client,
you would need to run the get.ASL script instead of the get.Glpk script,
however. If you want to pursue that option, OS has extensive documentation
and examples or I can point you to some places that specifically describe
how to use the AMPL client.

Cheers,

Ted

On Tue, Dec 22, 2015 at 6:37 PM, Patrick Wieschollek <
patrick at wieschollek.info> wrote:

> Hi,
>
> I hope this is the correct way to get in contact.
>
> The documentation does not cover how to use symphony to solve models from
> AMPL, although there are some flags to call symphony with a AMPL model file.
>
> To make the problem reproducible I created a docker-image:
> https://github.com/PatWie/symphony-docker
>
> which contains all steps from
> http://www.coin-or.org/SYMPHONY/man-5.1/node19.html
>
> (See
> https://github.com/PatWie/symphony-docker/blob/master/image/Dockerfile)
>
> However, I have the issue when calling
> "/var/symphony/bin/symphony -F /var/symphony/SYMPHONY/Datasets/sample.mod
> -D /var/symphony/SYMPHONY/Datasets/sample.dat"
>
> to get
> "
> Reading input file...
>
> ERROR: SYMPHONY can only read GMPL/AMPL files if GLPK is
> installed and the USE_GLPMPL compiler define is set.
> Exiting.
>
> "
>
> What are the missing steps?
>
> _______________________________________________
> Symphony mailing list
> Symphony at list.coin-or.org
> http://list.coin-or.org/mailman/listinfo/symphony
>
>


-- 
Dr. Ted Ralphs
Professor, Lehigh University
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted
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