Feat/956 compute iis highs by lisazeyen · Pull Request #957 · PyPSA/linopy

lisazeyen · 2026-09-15T15:32:51Z

Closes #956 (if applicable).

Changes proposed in this Pull Request

Adds HiGHS support to Model.compute_infeasibilities(), which previously only worked with
Gurobi and Xpress. HiGHS's IIS (irreducible infeasible subsystem) computation
is documented at
HiGHS: Advanced features — IIS
and exposed in highspy via Highs.getIis().

Extended testing in test/test_infeasibility.py and test/test_optimization.py::test_infeasible_model for Highs

Checklist

AI-generated content is marked (see AGENTS.md).
Code changes are sufficiently documented; i.e. new functions contain docstrings and further explanations may be given in doc.
Unit tests for new features were added (if applicable).
A note for the release notes doc/release_notes.rst of the upcoming release is included.
I consent to the release of this PR's code under the MIT license.

for more information, see https://pre-commit.ci

github-actions · 2026-09-15T15:37:57Z

Build cost — v1 vs legacy

v1 build peak & time relative to legacy, on this commit — not a comparison against master (that is CodSpeed).

peak — v1 / legacy	time — v1 / legacy

Full table (time + peak, mean)

benchmarks/drivers/test_build.py::test_build[basic-n=10]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.04919 (1.12)   │   15.03 (1.00) 
 (v1)         0.0441 (1.0)   │    15.00 (1.0) 

benchmarks/drivers/test_build.py::test_build[basic-n=250]
                 time (s)         peak (MiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)   0.0537 (1.12)   │   12.04 (1.00) 
 (v1)       0.04785 (1.0)   │    12.04 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=0]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02052 (1.13)   │   15.20 (1.0) 
 (v1)        0.01817 (1.0)   │   15.20 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=100]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.03391 (1.18)   │   44.93 (1.0) 
 (v1)        0.02878 (1.0)   │   44.93 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=50]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02337 (1.06)   │   11.51 (1.0) 
 (v1)        0.02207 (1.0)   │   11.51 (1.0) 

benchmarks/drivers/test_build.py::test_build[expression_arithmetic-n=10]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.05472 (1.11)   │   24.34 (1.06) 
 (v1)        0.04934 (1.0)   │    23.04 (1.0) 

benchmarks/drivers/test_build.py::test_build[expression_arithmetic-n=250]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.06038 (1.10)   │   16.12 (1.00) 
 (v1)        0.05472 (1.0)   │    16.12 (1.0) 

benchmarks/drivers/test_build.py::test_build[knapsack-n=10000]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)    0.013 (1.14)   │   752.18 (1.10) 
 (v1)       0.01137 (1.0)   │    685.15 (1.0) 

benchmarks/drivers/test_build.py::test_build[knapsack-n=100]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.01242 (1.09)   │   3.12 (1.33) 
 (v1)        0.01139 (1.0)   │    2.34 (1.0) 

benchmarks/drivers/test_build.py::test_build[kvl_cycles-severity=0]
                 time (s)          peak (MiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.0423 (1.37)   │   126.16 (1.44) 
 (v1)       0.03089 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[kvl_cycles-severity=100]
                  time (s)          peak (MiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.03979 (1.33)   │   126.16 (1.44) 
 (v1)        0.02996 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[kvl_cycles-severity=50]
                  time (s)          peak (MiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.03983 (1.30)   │   126.16 (1.44) 
 (v1)        0.03057 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[masked-n=100]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.02893 (1.01)   │    715.12 (1.0) 
 (v1)        0.02878 (1.0)   │   787.73 (1.10) 

benchmarks/drivers/test_build.py::test_build[masked-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02862 (1.14)   │   4.54 (1.27) 
 (v1)        0.02501 (1.0)   │    3.57 (1.0) 

benchmarks/drivers/test_build.py::test_build[merge_balance-severity=0]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.1976 (1.06)   │   704.12 (1.09) 
 (v1)         0.186 (1.0)   │    643.85 (1.0) 

benchmarks/drivers/test_build.py::test_build[merge_balance-severity=100]
                 time (s)        peak (MiB) 
 name                mean   │          mean 
────────────────────────────────────────────
 (legacy)   0.2052 (1.04)   │   18.34 (1.0) 
 (v1)        0.1978 (1.0)   │   18.34 (1.0) 

benchmarks/drivers/test_build.py::test_build[merge_balance-severity=50]
                 time (s)       peak (MiB) 
 name                mean   │         mean 
───────────────────────────────────────────
 (legacy)   0.2045 (1.06)   │   9.54 (1.0) 
 (v1)        0.1933 (1.0)   │   9.54 (1.0) 

benchmarks/drivers/test_build.py::test_build[milp-n=10]
                 time (s)        peak (KiB) 
 name                mean   │          mean 
────────────────────────────────────────────
 (legacy)   0.0402 (1.12)   │   3.77 (1.12) 
 (v1)       0.03596 (1.0)   │    3.37 (1.0) 

benchmarks/drivers/test_build.py::test_build[milp-n=50]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.04067 (1.14)   │   216.59 (1.10) 
 (v1)        0.03558 (1.0)   │    196.23 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance-severity=0]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.02069 (1.12)   │   938.49 (1.0) 
 (v1)        0.01849 (1.0)   │   938.49 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance-severity=100]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)   0.02172 (1.15)   │   9.66 (1.0) 
 (v1)         0.0188 (1.0)   │   9.66 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance-severity=50]
                 time (s)       peak (MiB) 
 name                mean   │         mean 
───────────────────────────────────────────
 (legacy)   0.0208 (1.12)   │   5.32 (1.0) 
 (v1)       0.01856 (1.0)   │   5.32 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=0]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)    0.01218 (1.0)   │   1.47 (1.0) 
 (v1)       0.01248 (1.02)   │   1.47 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=100]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)   0.01203 (1.10)   │   1.47 (1.0) 
 (v1)        0.01092 (1.0)   │   1.47 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=50]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)   0.01188 (1.06)   │   1.47 (1.0) 
 (v1)        0.01118 (1.0)   │   1.47 (1.0) 

benchmarks/drivers/test_build.py::test_build[piecewise-n=1000]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.1005 (1.06)   │   946.85 (1.06) 
 (v1)       0.09457 (1.0)   │    891.54 (1.0) 

benchmarks/drivers/test_build.py::test_build[piecewise-n=10]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.09745 (1.04)   │   12.01 (1.00) 
 (v1)        0.09379 (1.0)   │    11.99 (1.0) 

benchmarks/drivers/test_build.py::test_build[qp-n=1000]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.02579 (1.07)   │   147.70 (1.06) 
 (v1)        0.02409 (1.0)   │    139.87 (1.0) 

benchmarks/drivers/test_build.py::test_build[qp-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02644 (1.14)   │   2.60 (1.09) 
 (v1)        0.02314 (1.0)   │    2.38 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=0]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.0221 (1.20)   │   696.75 (1.03) 
 (v1)       0.01848 (1.0)   │    673.70 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=100]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.05699 (1.08)   │   137.97 (1.0) 
 (v1)        0.05258 (1.0)   │   137.97 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=50]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.03612 (1.00)   │   69.22 (1.0) 
 (v1)        0.03604 (1.0)   │   69.22 (1.0) 

benchmarks/drivers/test_build.py::test_build[sos-n=1000]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.02385 (1.13)   │   402.33 (1.00) 
 (v1)        0.02109 (1.0)   │    402.30 (1.0) 

benchmarks/drivers/test_build.py::test_build[sos-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02401 (1.10)   │   3.19 (1.19) 
 (v1)         0.0218 (1.0)   │    2.69 (1.0) 

benchmarks/drivers/test_build.py::test_build[sparse_network-n=10]
                  time (s)         peak (KiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.02625 (1.09)   │   29.00 (1.54) 
 (v1)        0.02413 (1.0)   │    18.84 (1.0) 

benchmarks/drivers/test_build.py::test_build[sparse_network-n=250]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.03417 (1.13)   │   37.95 (1.43) 
 (v1)        0.03029 (1.0)   │    26.51 (1.0) 

benchmarks/drivers/test_build.py::test_build[storage-n=10]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)    0.05045 (1.0)   │    410.93 (1.0) 
 (v1)       0.05092 (1.01)   │   427.84 (1.04) 

benchmarks/drivers/test_build.py::test_build[storage-n=250]
                 time (s)         peak (MiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)     0.06 (1.09)   │     9.94 (1.0) 
 (v1)       0.05516 (1.0)   │   10.22 (1.03)

📊 Interactive plots + CSV: download the semantics-report-v1-vs-legacy artifact from this run.

_{Report-only · not a gate · refreshed on every push · obsolete once legacy is dropped.}

codspeed · 2026-09-15T15:38:06Z

Merging this PR will degrade performance by 5.3%

⚠️

Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
❌ 4 regressed benchmarks
✅ 176 untouched benchmarks
⏩ 181 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	`BASE`	`HEAD`	Efficiency
❌	`test_to_lp[qp-n=1000]`	1.9 MB	2.6 MB	-24.84%
❌	`test_to_lp[nodal_balance_sparse-severity=50]`	2.8 MB	3.7 MB	-24.12%
❌	`test_to_lp[merge_balance-severity=0]`	2.7 MB	3.3 MB	-18.24%
❌	`test_to_lp[nodal_balance-severity=50]`	3.3 MB	3.7 MB	-10.5%
⚡	`test_to_lp[sparse_network-n=10]`	1,338.9 KB	733.8 KB	+82.47%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

_{Comparing feat/956-compute-IIS-highs (957cdd3) with master (718c0c1)²}

181 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on master (20648f5) during the generation of this report, so 718c0c1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

Drop the hasattr getIis guard in favor of fail-fast, move the highspy import to the top of the method, flatten the iis_strategy bitmask into named locals, and reuse the module-level solvers helper.

The available_solvers check already guarantees highspy is importable.

Their available_solvers membership already guarantees importability, matching the highs branch.

FabianHofmann

thanks @lisazeyen ; I added some refactoring to align the code and pulled up the release notes

lisazeyen and others added 5 commits September 15, 2026 17:27

feat: add highs to possible solvers for IIS

503e9e8

feat: add solverfeature IIS for Highs

ff2fc07

feat: add highs to the tests

a845964

docs: add release note

33f9708

[pre-commit.ci] auto fixes from pre-commit.com hooks

22e0db8

for more information, see https://pre-commit.ci

lisazeyen requested a review from FabianHofmann September 15, 2026 15:33

fix: make IIS strategy possible as user input

2c22b9a

FabianHofmann added enhancement New feature or request solver interface labels Sep 18, 2026

FabianHofmann added 4 commits September 22, 2026 12:40

refactor: tidy HiGHS IIS computation

dfa3512

Drop the hasattr getIis guard in favor of fail-fast, move the highspy import to the top of the method, flatten the iis_strategy bitmask into named locals, and reuse the module-level solvers helper.

docs: move HiGHS IIS note to upcoming release

66b5f64

refactor: drop redundant highspy import guard

40cba04

The available_solvers check already guarantees highspy is importable.

refactor: drop redundant import guards for gurobi and xpress

e8fe758

Their available_solvers membership already guarantees importability, matching the highs branch.

FabianHofmann approved these changes Sep 22, 2026

View reviewed changes

Merge branch 'master' into feat/956-compute-IIS-highs

957cdd3

FabianHofmann merged commit 0770dfe into master Sep 22, 2026
21 of 23 checks passed

FabianHofmann deleted the feat/956-compute-IIS-highs branch September 22, 2026 10:58

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Feat/956 compute iis highs - #957

Feat/956 compute iis highs#957
FabianHofmann merged 11 commits into
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feat/956-compute-IIS-highs

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Changes proposed in this Pull Request

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Build cost — v1 vs legacy

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Merging this PR will degrade performance by 5.3%

Performance Changes

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