I tried following the instructions on my MacBookAir, but it fails testing.
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.
Yes, but the instructions tell you to download 4.0.
Has anyone gotten it to work on Windows?
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.
I’ve been trying to do it with the command-line version of Ubuntu that can run inside Windows 10
but haven’t gotten everything to work yet.
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
/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?
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.
The actual statement is error reading file … no problem exists. It may be that the file is read but isn’t correct.
Can you run the .nl file from the command line using scipampl?
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.
SCIP does not support trig. functions including cosine:
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.