Hacktoberfest 2026:メンテナが10月に向けて印を付けた、オープンで初心者向けの issue。 Hacktoberfest の issue を見る

spec: rows emptied by absence are dropped silently; revisit strict refusal

オープン
#993 コメント 2 件 リアクション 0 件 担当者 0 名 GitHub で見る

メンテナーはふだん 1 日以内に返信

まだ誰も着手していません。

評価

難易度
5/5
見積もり時間
1週間以上
初心者へのやさしさ
30/100
issue の種類
機能追加
明瞭さ
おおむね明確
活発さ
活発
技術スタック
python
領域
backend

調査の方向性

Start with linopy/spec/builder.py::_check_live and run the minimal example from the issue. Read test/test_spec_builder.py::test_absence_takes_the_row_with_it and ::test_a_row_the_data_emptied_of_variables_is_refused to understand the current behavior. Done requires resolving the strictness and warning or edge-policy questions and adding tests for the chosen behavior.

索引モデルが issue の本文から書いたものです。

説明

discussion math-spec

In the long term I would like to have things strict, but for now this is fine. Tracking this so we can readdress it later.

[!NOTE]
The following content was generated by AI.

Describe the feature you'd like to see

With the move to mathspec 0.2.0 in #958, linopy/spec/builder.py::_check_live no longer refuses a constraint row that absence empties. It drops the row silently. This follows mathspec's documented semantics: absence spread through arithmetic "takes the row with it", and the first row of a bare shift "is not built".

Before (0a725f43), such a row raised SpecDataError ("N row(s) hold no variable term"), because a row that silently disappears no longer binds.

The current state after #958:

row behaviour
absent (null) row, e.g. x - shift(x) at the first snapshot dropped silently
bare masked Variable as a term not checked
present row with no variable, e.g. absence: zero against a binding side refused

Strict is the long-term goal. Open questions:

  • Opt-in strictness, e.g. add_spec(..., strict=True), or strict by default with an explicit edge policy in the spec (shift(..., edge=...))?
  • Warn at least with the count of rows dropped per constraint?
  • Does mathspec need a language-level way to state "this row may be dropped", so strict engines can tell intended from accidental absence?

Reasons it is relaxed for now: pypsa.yaml, its netcdf round trip and the spec_pypsa benchmark rely on a bare shift dropping the first snapshot.

Minimal example
import pandas as pd
import xarray as xr

import linopy

linopy.options["semantics"] = "v1"

spec = """
dimensions:
  snapshot: { dtype: int }
variables:
  p:
    dims: [snapshot]
    bounds: { lower: 0 }
constraints:
  no_faster_than_before:
    dims: [snapshot]
    expression: p <= shift(p, along=snapshot, offset=1)
objective: { sense: minimize, expression: sum(p) }
"""
sources = xr.Dataset(coords={"snapshot": pd.Index([0, 1, 2], name="snapshot")})
m = linopy.Model.from_spec(spec, sources)
print(m.constraints["no_faster_than_before"].labels.values)
# [-1  1  2]   -> row at snapshot 0 is dropped without error or warning

Tests pinning the current behaviour: test/test_spec_builder.py::test_absence_takes_the_row_with_it and ::test_a_row_the_data_emptied_of_variables_is_refused.

主要言語
Python
スター
259
フォーク
89
平均マージ
1日 18時間
マージ済み PR(30日)
26

環境構築

はじめの一歩

  1. issue を最後まで読み、次にプロジェクトのコントリビューションガイドを読みます。
  2. 着手することを issue にコメントします — 二人が同じ作業をするのを防げます。
  3. リポジトリをフォークし、ブランチを切って変更します。
  4. issue 番号を参照したプルリクエストを送ります。

PyPSA/linopy のほかの issue

PyPSA/linopy の issue をすべて見る

似ている issue

Python の issue をもっと見る

新しい issue をメールで受け取る

初心者向けの GitHub issue を短くまとめたダイジェスト。