How to completely uninstall AMPL from mac

Hi folks,

For some unexplained reason, when I reran an optimisation today (on AMPL IDE 4.0.0.202308171617) using the identical input files I used just before Christmas, it generated a different set of answers that are obviously flawed.

I’m running it on a mac (os.name=Mac OS X, os.version=13.6.3) so I dragged the entire Applications > AMPL directory to the bin, rebooted, reinstalled a fresh version using the installer package provided - but I am getting the same unexpected behaviour. I noticed that the supposed fresh install was shown as an ‘upgrade’ rather than an ‘install’ so I wonder if AMPL installs elements elsewhere on the hard drive and that my attempt to uninstall it was incomplete.

Searching for ‘uninstall’ on the support forum or the resources pages doesn’t reveal any manual instructions for how to uninstall AMPL IDE - can anyone suggest how to completely remove it from my mac so that I can try to reinstall it and see if that cures this odd behaviour?

Thanks very much!

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Hi @Stef_242,

Thank you for reaching out. All the relevant files are installed in /Applications/AMPL and to uninstall you can just drag to the trash bin. Other than that there are some files that may go to ~/Library/Application Support/amplide but that do not affect solver results.

Regarding the wrong solutions, in Release History — AMPL Resources you can see what was updated in recent releases. Which solver are you using?

Thanks @fdabrandao !

I’m using HiGHS and as you point out, the changelog does show some edits.

I don’t know exactly what version of HiGHS I was using before - is there a way for me to download and run some of the superseded solvers to determine which one introduced the error? I’ve not yet found any references explaining how to do that (or even to download a previous mac installer) so any suggestions would be very welcome!

We don’t have older versions of the installer, but at the end of Homepage for AMPL - AMPL Portal there is a table with download links for previous versions of HiGHS. You can try older versions by:

  • Downloading the package from that page.
  • Extracting and moving the highs executable to /Applications/AMPL/
  • In AMPL prompt run shell "xattrc -rc /Applications/AMPL/" to mark the new binaries as safe since they were installed manually.

Thanks @fdabrandao - I’d not seen that download area for the previous versions of the solvers!

I’ve successfully run shell "xattr -rc /Applications/AMPL" on one of the older HiGHS and it seems to work. I’ll work my way through and try to figure out which one causes the problem.

In the meantime, thanks so much for your very swift help!

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OK - I’ve confirmed a bug was introduced in highs.macos64.20230919 and that persists into the current version.

highs.macos64.20230831 is the last version that produces the expected results.

Thank you very much @fdabrandao for helping me find this!

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Hi @Stef_242,

Could you please open an issue in Issues · ampl/mp · GitHub with enough information for us to reproduce the issue?