Issues with the KNITRO solver on macOS Big Sur

[Danny Troy]

Hey everybody,

I have an issue with the KNITRO solver on my MacBook Pro running on the current version of macOS Big Sur (Version 11.3.1).

For my Masters program I'm required to use AMPL and specifically the KNITRO solver for optimization problems. When running the KNITRO solver following error always appears in the Ampl terminal (as attached in the 1st screenshot):

dyld: Library not loaded: /usr/local/opt/libomp/lib/libomp.dylib

Referenced from: /Applications/Ampl/knitro

Reason: image not found

error running knitro:

termination code 6

I could find some information (e.g. reinstalling via homebrew) but nothing I could work with because I do not have any prior knowledge in this regard. By the way I also opened the terminal file of KNITRO in my Ampl folder which showed me the same error in the terminal (see 2nd screenshot).

I would be grateful for a simple solution approach if existing.

Best regards from Germany!

[AMPL Google Group]

It appears that the Knitro library file is missing from your AMPL folder. So that we can track down the cause of this, please write back with the following information:

• The location from which you downloaded Knitro. (This could be a page on the AMPL website, or a special location associated with the course that you are taking.)
• A screenshot of the folder that contains the "knitro" file, showing the listing of files in that folder.
• The contents of the small file ampl.lic, if there is one in the same folder.

--
Robert Fourer
am...@googlegroups.com

{#HS:1516888952-104370#}

[Danny Troy]

Hey Robert,

thank your in advance for your quick response! 

1) I downloaded the Ampl folder (incl. Knitro) from the University's learning platform Ilias. This is the link for the folder (which probably won't be accessible w/o a university account): https://ilias.uni-mannheim.de/ilias.php?ref_id=1127341&cmd=view&cmdClass=ilrepositorygui&cmdNode=vi&baseClass=ilRepositoryGUI

Furthermore I also downloaded the Ampl IDE for macOS here: https://ampl.com/products/ide/

2) See 1st screenshot below

3) See 2nd Screenshot below

Best regards

Daniel

[AMPL Google Group]

Hi Danny,

As far as we know, this is an error that was fixed. However, your professor might have downloaded the bundles for your course as early as February 19, which would have been before the fix was made. As a test, we will re-generate the bundle and send you the two knitro files from it. Hopefully you will have them later on Friday.

--
Robert Fourer
am...@googlegroups.com

{#HS:1516888952-104370#}

On Tue, May 18, 2021 at 3:16 PM UTC, AMPL Modeling Language <am...@googlegroups.com> wrote:

Hey Robert, thank your in advance for your quick response! 1) I downloaded the Ampl folder (incl. Knitro) from the University's learning platform Ilias. This is the link for the folder (which probably won't be accessible w/o a university account): https://ilias.uni-mannheim.de/ilias.php?ref_id=1127341&cmd=view&cmdClass=ilrepositorygui&cmdNode=vi&baseClass=ilRepositoryGUI Furthermore I also downloaded the Ampl IDE for macOS here: https://ampl.com/products/ide/ 2) See 1st screenshot below 3) See 2nd Screenshot below Best regards Daniel AMPL Google Group schrieb am Dienstag, 18. Mai 2021 um 16:04:20 UTC+2: It appears that the Knitro library file is missing from your AMPL folder. So that we can track down the cause of this, please write back with the following information:

• The location from which you downloaded Knitro. (This could be a page on the AMPL website, or a special location associated with the course that you are taking.)
• A screenshot of the folder that contains the "knitro" file, showing the listing of files in that folder.
• The contents of the small file ampl.lic, if there is one in the same folder.

-- Robert Fourer [url=]am...@googlegroups.com

On Tue, May 18, 2021 at 2:02 PM UTC, AMPL Google Group <am...@googlegroups.com> wrote:

It appears that the Knitro library file is missing from your AMPL folder. So that we can track down the cause of this, please write back with the following information:

• The location from which you downloaded Knitro. (This could be a page on the AMPL website, or a special location associated with the course that you are taking.)
• A screenshot of the folder that contains the "knitro" file, showing the listing of files in that folder.
• The contents of the small file ampl.lic, if there is one in the same folder.

--
Robert Fourer
am...@googlegroups.com

[Danny Troy]

Hey Robert,

thank you very much for your help! So I'm waiting for the files to arrive and I will try to replace the old ones. I'll let you know if it works.

BR Daniel