fix: reject MultiIndex constant operands under v1 by FabianHofmann · Pull Request #1040 · PyPSA/linopy

FabianHofmann · 2026-10-22T08:36:05Z

Related to #846.

Note

The following was generated by AI.

Changes proposed in this Pull Request

Under v1, arithmetic or comparison between a variable/expression and a constant DataArray on a MultiIndex dimension failed with an opaque xarray error, or silently produced an expression over the MultiIndex:

import pandas as pd, xarray as xr, linopy
linopy.options["semantics"] = "v1"
m = linopy.Model()
x = m.add_variables(lower=0, coords=[pd.RangeIndex(2, name="a")], name="x")
mi = pd.MultiIndex.from_product([[0, 1], ["u", "v"]], names=["a", "b"])
c = xr.DataArray(range(4), coords={"s": mi}, dims="s")
x + c  # ValueError: a already exists as coordinate or variable name.

broadcast_to_coords (the choke point for constant operands) now rejects, under v1, a MultiIndex dimension the target coords don't already carry. It raises the same message as add_variables, with the reset_index hint. This covers + - * /, reflected ops, <= >= == and add_constraints.
Legacy is unchanged.
A parametrized test covers operations × Variable/LinearExpression operand × colliding/fresh level names.

This is a step toward removing the MultiIndex machinery at 1.0 (#846).

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.

github-actions · 2026-10-22T08:39:16Z

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)   0.06865 (1.12)   │   15.03 (1.00) 
 (v1)        0.06111 (1.0)   │    15.00 (1.0) 

benchmarks/drivers/test_build.py::test_build[basic-n=250]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.07702 (1.14)   │   12.04 (1.00) 
 (v1)        0.06736 (1.0)   │    12.04 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=0]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.02885 (1.11)   │   15.20 (1.0) 
 (v1)        0.02601 (1.0)   │   15.20 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=100]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.04451 (1.07)   │   44.93 (1.0) 
 (v1)        0.04148 (1.0)   │   44.93 (1.0) 

benchmarks/drivers/test_build.py::test_build[cumsum-severity=50]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.03262 (1.10)   │   11.51 (1.0) 
 (v1)        0.02952 (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)   0.07549 (1.09)   │   24.45 (1.06) 
 (v1)        0.06924 (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)   0.08641 (1.10)   │   16.12 (1.00) 
 (v1)        0.07863 (1.0)   │    16.12 (1.0) 

benchmarks/drivers/test_build.py::test_build[knapsack-n=10000]
                time (s)          peak (KiB) 
 name               mean   │            mean 
─────────────────────────────────────────────
 (legacy)   0.018 (1.08)   │   752.18 (1.10) 
 (v1)       0.0166 (1.0)   │    685.15 (1.0) 

benchmarks/drivers/test_build.py::test_build[knapsack-n=100]
                 time (s)        peak (KiB) 
 name                mean   │          mean 
────────────────────────────────────────────
 (legacy)   0.0175 (1.09)   │   3.12 (1.33) 
 (v1)       0.01612 (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)   0.06035 (1.38)   │   126.16 (1.44) 
 (v1)        0.04359 (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)   0.05943 (1.36)   │   126.16 (1.44) 
 (v1)        0.04356 (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)   0.05953 (1.43)   │   126.16 (1.44) 
 (v1)         0.0415 (1.0)   │     87.71 (1.0) 

benchmarks/drivers/test_build.py::test_build[masked-n=100]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.04105 (1.04)   │    712.45 (1.0) 
 (v1)        0.03943 (1.0)   │   787.73 (1.11) 

benchmarks/drivers/test_build.py::test_build[masked-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.04107 (1.16)   │   4.62 (1.29) 
 (v1)        0.03551 (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)   0.2757 (1.03)   │   707.91 (1.10) 
 (v1)        0.2673 (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)   0.293 (1.06)   │   18.34 (1.0) 
 (v1)       0.2772 (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)   0.2876 (1.05)   │   9.54 (1.0) 
 (v1)        0.2738 (1.0)   │   9.54 (1.0) 

benchmarks/drivers/test_build.py::test_build[milp-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.05754 (1.13)   │   3.85 (1.14) 
 (v1)          0.051 (1.0)   │    3.37 (1.0) 

benchmarks/drivers/test_build.py::test_build[milp-n=50]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.05698 (1.12)   │   216.98 (1.11) 
 (v1)        0.05097 (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)   0.02899 (1.10)   │   938.49 (1.0) 
 (v1)        0.02644 (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)   0.03071 (1.10)   │   9.66 (1.0) 
 (v1)        0.02793 (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)   0.03011 (1.11)   │   5.32 (1.0) 
 (v1)        0.02722 (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)   0.01254 (1.01)   │   1.29 (1.0) 
 (v1)        0.01245 (1.0)   │   1.29 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=100]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)   0.01244 (1.01)   │   1.29 (1.0) 
 (v1)        0.01233 (1.0)   │   1.29 (1.0) 

benchmarks/drivers/test_build.py::test_build[nodal_balance_sparse-severity=50]
                  time (s)       peak (MiB) 
 name                 mean   │         mean 
────────────────────────────────────────────
 (legacy)   0.01249 (1.01)   │   1.29 (1.0) 
 (v1)        0.01234 (1.0)   │   1.29 (1.0) 

benchmarks/drivers/test_build.py::test_build[piecewise-n=1000]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.1391 (1.06)   │   946.85 (1.06) 
 (v1)        0.1306 (1.0)   │    891.54 (1.0) 

benchmarks/drivers/test_build.py::test_build[piecewise-n=10]
                time (s)         peak (KiB) 
 name               mean   │           mean 
────────────────────────────────────────────
 (legacy)   0.137 (1.04)   │   12.01 (1.00) 
 (v1)       0.1321 (1.0)   │    11.99 (1.0) 

benchmarks/drivers/test_build.py::test_build[qp-n=1000]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.03621 (1.10)   │   147.70 (1.06) 
 (v1)        0.03305 (1.0)   │    139.87 (1.0) 

benchmarks/drivers/test_build.py::test_build[qp-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.03583 (1.09)   │   2.60 (1.09) 
 (v1)        0.03281 (1.0)   │    2.38 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=0]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.03012 (1.11)   │   704.59 (1.05) 
 (v1)        0.02721 (1.0)   │    673.70 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=100]
                  time (s)         peak (MiB) 
 name                 mean   │           mean 
──────────────────────────────────────────────
 (legacy)   0.07677 (1.07)   │   137.97 (1.0) 
 (v1)         0.0717 (1.0)   │   137.97 (1.0) 

benchmarks/drivers/test_build.py::test_build[rolling-severity=50]
                  time (s)        peak (MiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.04751 (1.04)   │   69.22 (1.0) 
 (v1)        0.04565 (1.0)   │   69.22 (1.0) 

benchmarks/drivers/test_build.py::test_build[sos-n=1000]
                  time (s)          peak (KiB) 
 name                 mean   │            mean 
───────────────────────────────────────────────
 (legacy)   0.03461 (1.13)   │   402.37 (1.00) 
 (v1)        0.03063 (1.0)   │    402.30 (1.0) 

benchmarks/drivers/test_build.py::test_build[sos-n=10]
                  time (s)        peak (KiB) 
 name                 mean   │          mean 
─────────────────────────────────────────────
 (legacy)   0.03384 (1.13)   │   3.23 (1.20) 
 (v1)        0.03003 (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)   0.03718 (1.09)   │   29.00 (1.54) 
 (v1)        0.03405 (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)   0.04919 (1.15)   │   37.95 (1.43) 
 (v1)        0.04279 (1.0)   │    26.51 (1.0) 

benchmarks/drivers/test_build.py::test_build[storage-n=10]
                 time (s)          peak (KiB) 
 name                mean   │            mean 
──────────────────────────────────────────────
 (legacy)   0.0728 (1.03)   │    410.14 (1.0) 
 (v1)       0.07092 (1.0)   │   427.84 (1.04) 

benchmarks/drivers/test_build.py::test_build[storage-n=250]
                 time (s)         peak (MiB) 
 name                mean   │           mean 
─────────────────────────────────────────────
 (legacy)   0.0789 (1.00)   │     9.94 (1.0) 
 (v1)       0.07864 (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 · 2026-10-22T08:40:04Z

Merging this PR will not alter performance

✅ 181 untouched benchmarks
⏩ 181 skipped benchmarks¹

_{Comparing fix/v1-multiindex-constant (c8c172e) with master (0af6929)}

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. ↩

fix: reject MultiIndex constant operands under v1 with linopy's error

c8c172e

FabianHofmann merged commit 54291d4 into master Oct 22, 2026
24 checks passed

FabianHofmann deleted the fix/v1-multiindex-constant branch October 22, 2026 09:13

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fix: reject MultiIndex constant operands under v1 - #1040

fix: reject MultiIndex constant operands under v1#1040
FabianHofmann merged 1 commit into
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fix/v1-multiindex-constant

FabianHofmann commented Oct 22, 2026

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FabianHofmann commented Oct 22, 2026

Changes proposed in this Pull Request

Checklist

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github-actions Bot commented Oct 22, 2026

Build cost — v1 vs legacy

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codspeed Bot commented Oct 22, 2026

Merging this PR will not alter performance

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