"Unable to read LP model" but HiGHS itself works

[fuglede]

If I run this model through the demo website, I get a

Error: Unable to read LP model (see http://web.mit.edu/lpsolve/doc/CPLEX-format.htm). HiGHS error

yet HiGHS proper (tested with Running HiGHS 1.5.1 [date: 2023-04-19, git hash: be21711c9]) manages to read it just fine (after saving it with an .lp extension). Edit: Just tried with HiGHS 1.6.0 off of the current master, and that also works.

[jajhall]

Is this related to the example you've posted as part of a HiGHS issue?

[fuglede]

@jajhall It came up in the same line of work, but no, I believe I isolated it into two separate issues.

(And for reference, the other issue is ERGO-Code/HiGHS#1448)

[jajhall]

OK, thanks. For this issue (#34), I don't know what's changed that might affect this model, but what version of HiGHS are you using?

[fuglede]

https://github.com/lovasoa/highs-js/ bundles HiGHS @ 8194724, corresponding to HiGHS 1.2.2. I tried building this old version of HiGHS and found the same issue; it wouldn't read this particular .lp.

So, a submodule bump should do the job. I've added one (to 1.6.0) as a PR in #35 if that makes an update easier.

[jajhall]

That's a very out-of-date version of HiGHS! There have been many updates to the .LP file reader since then

[lovasoa]

Yes, we are stuck on an old version because the API did not expose everything we needed, so we resorted to parsing the text output, and its format changed.

[fuglede]

I can confirm that this is no longer an issue after the 1.0.0 highs-js update.