Slow performance of gauge computation
For some reason gauge fixing is extremely slow in CI (see the logs):
========================== slowest 10 test durations ===========================
900.51s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[2-honeycomb-half-ring]
413.08s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[3-honeycomb-half-ring]
137.30s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[3-square-half-ring]
62.77s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[2-honeycomb-circle]
60.67s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[3-honeycomb-circle]
31.25s call kwant/physics/tests/test_gauge.py::test_phases[cubic-finite-3]
20.35s call kwant/physics/tests/test_gauge.py::test_phases[cubic-finite-2]
17.62s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[3-square-circle]
15.78s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[3-honeycomb-rectangle]
10.37s call kwant/physics/tests/test_gauge.py::test_minimal_cycle_basis[2-honeycomb-rectangle]
================== 389 passed, 2 warnings in 1767.99 seconds ===================
The same tests don't take any significant time on my laptop, so this might be a faulty configuration in CI. Still if it is something unrelated to CI (misconfigured compiler or anything alike), this could be serious enough to hold off releasing the feature.