Julian Hall comments

Results 551 comments of


                                            Julian Hall

saved MIP solutions pool is empty when solution is found during presolve

Well spotted. No reason not to store it - for completeness

saved MIP solutions pool is empty when solution is found during presolve

Closed by #1742

User callback interrupt (HighsCallbackDataIn%user_interrupt, Fortran syntax) does not seem to work for release 1.7.0

Not all callback permit an interrupt. Which one are you setting to be "on"?

User callback interrupt (HighsCallbackDataIn%user_interrupt, Fortran syntax) does not seem to work for release 1.7.0

`kHighsCallbackMipImprovingSolution` doesn't allow an interrupt: if you set `HighsCallbackDataIn%user_interrupt value` then it is ignored. Note that the improving solution callback may not be called often, so it's not a great...

User callback interrupt (HighsCallbackDataIn%user_interrupt, Fortran syntax) does not seem to work for release 1.7.0

Since we have a C++ unit test for this interrupt, > TEST_CASE("highs-callback-mip-interrupt", "[highs-callback]") { I'm wondering whether there's a problem when using the callback from Fortran - and possibly C...

Presolve leads to multiple 'WARNING: Untransformed solution with objective[...] is violated by 0.42 for the original model'

@Timeroot Could you let us have an example model?

Presolve leads to multiple 'WARNING: Untransformed solution with objective[...] is violated by 0.42 for the original model'

Strange, I get the following with githash https://github.com/ERGO-Code/HiGHS/commit/93f1876e453eeec2d16e2a0c95874d0ef12c5b23 built on Linux. Are you running on Windows? > Running HiGHS 1.5.1 [date: 2023-04-18, git hash: 93f1876e4] Copyright (c) 2023 HiGHS under...

HiGHS Falsely Declares a MILP as Integer-Infeasible

This issue has been tracked down to implied column bounds being incorrect after the aggregator is applied: the new terms introduced can lead to an increase (decrease) in the implied...

In CholeskyFactor.resize the index can exceed the vector length.

This will be fixed when `fix-1129` is merged into `latest`

highs solver fails test in Ubuntu when showing log messages

The current [pypi](https://pypi.org/project/highspy/) version of HiGHS is still the rogue v1.5.3 in which setLogCallback was deleted from highspy. However, [v1.7.1.dev1](https://pypi.org/project/highspy/#history) is now available. This allows the new [general callback mechanism](https://ergo-code.github.io/HiGHS/stable/callbacks/)...