HiGHS

A new (2026) solver interface to the HiGHS linear (LP) and mixed-integer program (MIP) solver has recently been added to ASCEND. We welcome any feedback!

This solver successfully solves the following example problems (see ascend/solver/test/test_highs.c, models in models/test/mip models/test/highs):

• a simple single-MODEL trivial linear program models/test/ipopt/lp1.a4c
• a hierarchical model that yields an LP models/test/ipopt/lp_structured.a4c
• a simple MIP models/test/mip/mip_mixed.a4c
• a simplified 'capacitated facility-location problem' models/test/mip/facility_location.a4c
• a classic travellling salesman (TSP) problem models/test/mip/tsp_mtz8.a4c
• the 'whiskas' blending problem models/test/highs/blend_whiskas2.a4c
• the Netlib 'AFIRO' benchmark problem models/test/highs/afiro.a4c

Building HiGHS for use with ASCEND

Tested on Ubuntu 24.04:

cd ~
git clone https://github.com/ERGO-Code/HiGHS.git highs
cd highs
cmake -S . -B build \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX=$HOME/.local \
  -DBUILD_SHARED_LIBS=ON \
  -DCMAKE_INSTALL_RPATH=$HOME/.local/lib
cmake --build build -j
cmake --install build

Testing HiGHS with ASCEND

To run the CUnit test suite for HiGHS, use the following commands:

cd ~/ascend
scons -j4 test
./a4 cutest solver_highs

Please make sure your ASCEND code is up to date, and note that you will need the latest patched version of CUnit. We're working on getting this version released and distributed, but for now it needs to be compiled from source.

Reference

• HiGHS Github page