Has anyone gotten SCIP 4.0 to work with Julia?

Specific Domains Optimization (Mathematical)
1

I tried following the instructions on my MacBookAir, but it fails testing.

2

As the SCIP.jl readme states:

Note that support for OS X is currently broken with the update to SCIP 4.0.0.

Follow the discussion here.

1 Like
3

Yes, but the instructions tell you to download 4.0.

Has anyone gotten it to work on Windows?

4

We have SCIP 4.0.0 working with Julia via AmplNLWriter.jl on a Linux machine. The transition from SCIP 3.x was super easy.

1 Like
5

I’ve been trying to do it with the command-line version of Ubuntu that can run inside Windows 10
(​How to get started with Ubuntu and Bash on Windows 10 | ZDNET)
but haven’t gotten everything to work yet.

6

When I try to call SCIP on Ubuntu using AMPL I get the following error message:

could not spawn Home/frank/scipoptsuite-4.0.0/scip-4.0.0/interfaces/ampl/bin/sciampl /home/frank/.julia/v0.5/AmplNLWriter/.solverdata/tmpIL6x3b.nl -AMPL: no such file or directory (ENOENT)

Calling Ipopt via AMPL does work, however

7

Go into /home/frank/.julia/v0.5/AmplNLWriter/.solverdata/ and see if the temporary file is being created. Also check the path to the scipampl executable. Should it be /home/frank/… and …/scipampl?

8

I fixed up the path to scipampl and am now getting an error message from SCIP that the temporary file is not found even though I can find it. I’m wondering if it is a question of the permission for the directory the temporary file is in.

9

The actual statement is error reading file … no problem exists. It may be that the file is read but isn’t correct.

10

Can you run the .nl file from the command line using scipampl?

Alex

11

When I did that, I got an error message that cos is not supported. I changed the problem in Julia to a quadratic problem and it ran. I had thought that SCIP can do Ipopt searches with integer variables but clearly was mistaken. Thanks for your help.

12

Hello Frank,

SCIP does not support trig. functions including cosine:
http://scip.zib.de/doc/html/FAQ.php#minlptypes

For solving MINLPs, give Bonmin or Pajarito.jl a try. I suspect with your problem these solves cannot guarantee a globally optimal solution.

Also, when solving MINLPs, it is critical to compile SCIP with support for IPOPT.
http://scip.zib.de/doc/html/MAKE.php

Alex

1 Like