limen.cohort.sfc

Canonical docs

Cohort

In the research projects

The Compiled project walk_forward scenario establishes the recorded fold identities that compatible Cohort members retain. These selectors are optional Python component APIs. The YAML assessment path exposes metric, direction, top_k and folds; it does not load this selector registry. The Cohort component boundary distinguishes those controls.

What this package owns

Owns the built-in selector strategies that turn completed-experiment artifacts into a list of permutation ids for Cohort, plus the BUILTIN_SELECTORS registry that names them. Does not own cohort aggregation itself (owned by limen.cohort.Cohort) or experiment execution.

Key entry points

Entry point	Use case	Notes
`BUILTIN_SELECTORS`	Name-to-selector registry	Maps `'all'`, `'top_n'`, `'backtest_pareto'`, `'diverse_metrics'`
`all.select`	Use every round	Default; preserves omitted-`permutation_ids` behavior
`top_n.select`	Rank by one numeric `results.csv` column	Requires `results.csv` in context
`backtest_pareto.select`	Trading-metric Pareto selection	Uses backtest return/risk columns
`diverse_metrics.select`	Spread selection across metric space	Favors complementary rather than similar rounds

Adjacent modules

limen.cohort.Cohort consumes the ids these selectors return.
limen.experiment produces the artifacts (results.csv, backtest columns) selectors read.

Quick orientation

Module or family	Responsibility
`all.py`	Select every permutation
`top_n.py`	Rank by a numeric results column
`backtest_pareto.py`	Pareto front over trading metrics
`diverse_metrics.py`	Diverse spread across metric space

text · README.md

1sfc/2├── README.md3├── __init__.py4├── all.py5├── backtest_pareto.py6├── diverse_metrics.py7└── top_n.py

Merged source PR · 87894eb8Package layout · Limen 6.0.1 · current package validation · package source

Things to know

Every selector shares the signature select(context, *, ...). The selector result must ultimately contain nonempty string permutation IDs because Cohort rejects non-string entries during binding.
context is a SelectorContext (dict[str, Any]) carrying artifacts such as context['results']; each selector validates the keys it needs and raises ValueError when they are missing.
top_n requires a Polars results.csv frame. A frame with no usable numeric ranking rows returns []; Cohort then rejects the empty selection. A missing or wrong-typed frame raises immediately.