Update HiGHS to version 1.6.0

[fuglede]

This updates the HiGHS submodule to https://github.com/ERGO-Code/HiGHS/releases/tag/v1.6.0.

[lovasoa]

This has been raised before. You need to update the solution parsing code if you want to upgrade highs

[lovasoa]

see #29

[lovasoa]

highs-js/src/post.js

Line 162 in 0f2694d

function parseResult(lines, status) {

[jajhall]

Note that the original code use to parse the solution was the human-readable form. It's vastly better and easier to parse the computer-readable solution file, so I recommend that this is done if you're updating the solution parsing code

[lovasoa]

@jajhall does the computer-readable format have the same information as the human-readable format in the latest versions ?

[fuglede]

It would also be nice to simply read it off the Highs object itself (so as to avoid parsing another file format in a context, where all that's available is a virtual file system in the first place). But, as far as I can tell, that involves adjusting or appending to the C API, as that's all that's available here for now.

For the particular issue with IsLinear and IsQuadratic, I would propose simply getting rid of them altogether: I don't have the imagination to see a scenario where the user doesn't already know if their model has quadratic terms prior to running it, and whether they have integer variables or not (although that can also be read off the "Type" information that is now available in all cases).

[jajhall]

@jajhall does the computer-readable format have the same information as the human-readable format in the latest versions ?

It has all the solution information, that's for sure. However, now you ask, I remember the issue of you wanting the bounds on the variables, and getting this from the human-readable format. Is that so?

[jajhall]

It would also be nice to simply read it off the Highs object itself (so as to avoid parsing another file format in a context, where all that's available is a virtual file system in the first place). But, as far as I can tell, that involves adjusting or appending to the C API, as that's all that's available here for now.

The solution is immediately available via the C API. Call Highs_getSolution and, where relevant, Highs_getBasis

[lovasoa]

I'd be ok with removing isLinear and isQuadratic (bumping the version number, because that would not be backwards compatible).

But we still need to throw a js error on error. I saw you removed that test.

[lovasoa]

We also need to update the README, since we changed the solution format

[fuglede]

We also need to update the README, since we changed the solution format

Should be covered already unless I missed something.

[lovasoa]

ok, let's go

[fuglede]

Wonderful, thanks for taking the time to review, @lovasoa!

[lovasoa]

thanks for your work, @fuglede