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feat: COOLEST standard interop — profile converters + template import/export #612

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feat: COOLEST standard interop — profile converters + template import/export#612

Description

@Jammy2211
Jammy2211
opened on Jul 16, 2026

Overview

Preparation for modeling ~18,000 Euclid DR1 lenses: PyAutoLens results must be exchangeable with lenstronomy/herculens/Glee via the COOLEST standard (https://github.com/aymgal/COOLEST). This task adds a conversion layer at the model I/O boundary covering all profiles COOLEST defines — internals unchanged (sampling stays on (e1,e2); no internal convention flip), per the Slack consensus (Sonnenfeld, Galan). The intermediate-axis question is handled by a follow-up PowerLawIntermediate + herculens-parity task (PyAutoMind/draft/feature/autolens/coolest_powerlaw_herculens_parity.md).

Plan

  • PyAutoGalaxy: new autogalaxy/interop/coolest/ package — pure, dependency-free bidirectional parameter converters for every COOLEST-defined light/mass profile (ellipticity, angle, intermediate-axis radius conventions), reusing autogalaxy/convert.py.
  • PyAutoLens: new autolens/interop/coolest.py — COOLEST JSON template import/export of full lens models (analytic profile parameters only) via the coolest pip package as an optional dependency.
  • Explicit, documented Einstein-radius definition on export (COOLEST intermediate-axis profile parameter; distinguished from the DR1 tangential-critical-curve definition).
  • Round-trip + numerical-certification tests for every √q / angle factor in both repos.
  • Workspace guide + workspace_test script as a follow-up PR behind the library-first merge gate.
Detailed implementation plan

Affected Repositories

  • PyAutoLens (primary)
  • PyAutoGalaxy

Branch Survey

Repository Current Branch Dirty?
./PyAutoGalaxy main clean
./PyAutoLens main paper_jax/paper.md modified (pre-existing, unrelated)

Suggested branch: feature/coolest-standard-support
Work classification: Library (workspace follow-up)
Worktree root: ~/Code/PyAutoLabs-wt/coolest-standard-support/

Convention facts (verified against coolest.readthedocs.io)

Quantity COOLEST PyAutoGalaxy/PyAutoLens
Coordinates cartesian (x right, y up), arcsec (y, x) grids, arcsec
Position angle CCW from +y (East-of-North), (-90°, +90°] CCW from +x, (-45°, 135°] (autogalaxy/convert.py) → φ_coolest = angle_ag − 90° renormalized
Ellipticity q = b/a + PA (e1, e2) ell_comps — ell_comps_from / axis_ratio_and_angle_from
Radii (r_eff, θ_E) intermediate axis r = √(a·b) = √q·a profile-specific; PowerLaw uses the 2/(q^-½+q^½) rescale (profiles/mass/total/power_law.py) — per-profile factors derived and numerically certified
Shear γ_ext, φ_ext (gamma_1, gamma_2) — shear_magnitude_and_angle_from
Template I/O coolest pip package (coolest.template) new optional dependency in PyAutoLens

Implementation Steps

Phase A — PyAutoGalaxy autogalaxy/interop/coolest/

  1. conventions.py — angle (+x ↔ East-of-North), (e1,e2) ↔ (q, PA), (y,x) ↔ (x,y) centre swap, per-profile radius-factor helpers. Reuse autogalaxy/convert.py; do not duplicate its math.
  2. light.py — ag.lp.Sersic ↔ COOLEST Sersic (effective-radius factor audited against ag's elliptical-radius definition); shapelets if supported by the installed coolest version.
  3. mass.py — ag.mp.Isothermal ↔ SIE, ag.mp.PowerLaw ↔ PEMD/EPL (θ_E intermediate-axis conversion), ag.mp.NFW ↔ NFW, ag.mp.ExternalShear ↔ ExternalShear, ag.mp.MassSheet ↔ convergence sheet if defined.
  4. Converters are dict-in/dict-out on plain floats (no coolest import in autogalaxy — zero new dependencies). Unsupported profiles raise a clear, named error (no silent skips).
  5. Tests test_autogalaxy/interop/ (numpy-only): per-profile round-trip identity + numerical certification — evaluate the ag profile and the profile reconstructed from its COOLEST parameters, assert equal convergence/deflections; for PowerLaw assert the analytic √q relation between θ_E definitions.

Phase B — PyAutoLens autolens/interop/coolest.py
6. to_coolest(galaxies_or_tracer, file_path) — export analytic profile parameters into a COOLEST JSON template (lensing entities from lens/source galaxies, redshifts from Galaxy.redshift), via the Phase A registry. Lazy coolest import with informative error; pip install autolens[coolest] extra; added to test/dev extras so CI exercises it.
7. from_coolest(file_path) -> Tracer — read a template, build ag/al profiles via the inverse mappings (built to consume Sonnenfeld's golden-lens JSONs).
8. Einstein-radius definition documented in module docstring + template metadata.
9. Tests test_autolens/interop/: full-model round-trip (PowerLaw + Shear lens, Sersic light + Sersic source), template written and re-read with coolest.template, parameters equal to input; end-to-end convergence/deflection equality on a grid.

Phase C — workspace follow-up PR (after library merge)
10. Minimal autolens_workspace/scripts/guides/ COOLEST example + autolens_workspace_test round-trip script.

Key Files

  • PyAutoGalaxy/autogalaxy/convert.py — existing (e1,e2)/(q,PA)/shear converters to reuse
  • PyAutoGalaxy/autogalaxy/profiles/mass/total/power_law.py — the 2/(q^-½+q^½) Einstein-radius rescale to map
  • PyAutoGalaxy/autogalaxy/interop/coolest/{conventions,light,mass}.py — new
  • PyAutoLens/autolens/interop/coolest.py — new
  • test_autogalaxy/interop/, test_autolens/interop/ — new tests

Original Prompt

Click to expand starting prompt

See PyAutoMind/active/coolest_standard_support.md (filed from the COOLEST Slack thread with Alessandro Sonnenfeld and Aymeric Galan; original request verbatim inside).

Activity

  1. Jammy2211 commented on Jul 16, 2026

    @Jammy2211
    Jammy2211
    on Jul 16, 2026
    CollaboratorAuthor

    Library PRs Created

    Heart was RED on 6 pre-existing, unrelated reasons at ship time; shipped through on explicit user acknowledgement (commit/push/PR-open only).

    API changes: Added only (new ag.interop / al.interop namespaces + coolest extra) — no workspace script is affected (grep confirms no interop usage).

    Next:

    1. Merge both PRs (library-first), then a minimal autolens_workspace COOLEST guide + autolens_workspace_test round-trip script as a follow-up PR (Phase C).
    2. Follow-up task (filed, starts after this merges): PowerLawIntermediate profile + herculens EPL cross-code parity via a shared COOLEST file — PyAutoMind/draft/feature/autolens/coolest_powerlaw_herculens_parity.md.
  2. Jammy2211
    added a commit that references this issue on Jul 17, 2026

    Fix COOLEST interop relative file paths

    a15744d

  3. Jammy2211 commented on Jul 17, 2026

    @Jammy2211
    Jammy2211
    on Jul 17, 2026
    CollaboratorAuthor

    Phase C Shipped — workspace PRs open

    Also merged this session: the library PRs PyAutoGalaxy#501 + PyAutoLens#613, and the corrective PyAutoLens#615 (the coolest JSONSerializer rejects relative paths; to_coolest/from_coolest now absolutize — found by running the guide, regression-tested).

    Note: the guide is named coolest_interop.py because a guides/coolest.py shadows the coolest package (script dir is on sys.path).

    Remaining: merge the two workspace PRs (library-first gate satisfied — upstream MERGED), then issue the follow-up task draft/feature/autolens/coolest_powerlaw_herculens_parity.md (PowerLawIntermediate + herculens parity).

  4. Jammy2211 commented on Jul 17, 2026

    @Jammy2211
    Jammy2211
    on Jul 17, 2026
    CollaboratorAuthor

    Shipped — 2026-07-17

    PRs (all MERGED)

    Summary

    COOLEST interop is live on all mains: ag.interop.coolest parameter converters (derived + numerically certified √q/angle factors) and al.interop.coolest.to_coolest/from_coolest JSON template I/O, with a workspace guide and a workspace_test validation script (round trip to 8.9e-16). Conversion sits at the model I/O boundary; internal conventions unchanged.

    Session Notes

    • A workspace script named coolest.py shadows the coolest package — guide is coolest_interop.py.
    • notebooks/weak/*.ipynb are stale on autolens_workspace main (regeneration diffs them) — worth a separate sweep.
    • Validation against Sonnenfeld's golden-lens templates (euclid-sgs GitLab, auth) remains a human step via from_coolest.
    • Next: follow-up task draft/feature/autolens/coolest_powerlaw_herculens_parity.md — PowerLawIntermediate profile + herculens EPL parity via a shared COOLEST file.
  5. Jammy2211
    closed this as completedon Jul 17, 2026
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