CodeEli Capabilities Reference

Status: active Scope: cross-cutting Type: research Last reviewed: 2026-05-15

This note records which parts of the local CodeEli checkout are currently relevant to Buffalo Wings work. It is intended to preserve implementation conclusions from exploratory discussions so the same source review does not need to be repeated later.

CodeEli should be treated as a source of algorithm references, test ideas, and mathematical constructions. It should not be treated as the architecture source of truth for Buffalo Wings, which remains schema-first, diagnostics-oriented, Python-native, and Splipy-backed for NURBS workflows.

Purpose

Record external CodeEli capabilities and source files that are worth revisiting for future Buffalo Wings work.

How To Use This Note

  • Use it for implementation inspiration, mathematical references, and exploratory follow-up.

  • Do not use it as the source of truth for Buffalo Wings runtime or schema architecture.

  • Prefer the active architecture docs when deciding what Buffalo Wings should expose publicly.

Current Status Summary

Buffalo Wings already covers the main CodeEli-derived CST runtime features that were initially of interest. Those already-covered areas include canonical CST evaluation, canonical CST derivatives, exact canonical CST-to-Bezier conversion, and constrained Bezier degree demotion.

The main near-term capability that Buffalo Wings does not yet implement is fitting arbitrary airfoils to an explicit CST parameterization.

The question of whether downstream geometry should be reduced to cubic degree is intentionally deferred. That policy decision should be made when Buffalo Wings starts emitting geometry for CAD-facing export or other consumers that materially prefer or require cubic curves or surfaces.

Near-Term Reference Targets

CST Fitting

This is the highest-value remaining CodeEli reference for near-term Buffalo Wings work. It aligns with the current downstream need to fit arbitrary airfoils to compact CST representations for Buffalo Panel-oriented workflows.

Primary CodeEli references:

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/curve/piecewise_cst_airfoil_fitter.hpp

  • /home/ddmarsha/develop/Code-Eli/include/eli/mutil/opt/least_squares.hpp

What is useful there:

  • point normalization into a CST-friendly frame,

  • designated versus actual leading-edge handling,

  • constrained least-squares coefficient recovery,

  • optional trailing-edge slope constraints,

  • and reconstruction of a CST airfoil from solved coefficients.

Buffalo Wings landing zone:

  • src/buffalo_wings/airfoil/internal/conversion/fit_to_cst.py

Buffalo Wings adaptation notes:

  • preserve explicit solver choice, tolerances, convergence handling, and diagnostics,

  • return structured fit-quality information rather than only a reconstructed airfoil,

  • keep fitting as an explicit conversion workflow rather than a hidden normalization path,

  • and adapt the mathematics to Buffalo Wings public runtime types rather than mirroring CodeEli class structure.

Deferred Compatibility Decision

Cubic Reduction

CodeEli contains a cubic reduction helper and broader Bezier utility code.

Relevant CodeEli reference:

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/utility/bezier.hpp

Current Buffalo Wings conclusion:

  • cubic reduction is not a near-term roadmap commitment,

  • and the decision about whether to reduce exported geometry to cubic degree should be made only when a CAD-facing or similarly constrained downstream consumer makes that choice concrete.

Until then, the existing Buffalo Wings Bezier promotion and constrained demotion support is sufficient for current local coefficient-space work.

Promising Non-CST References

The following CodeEli areas look promising for future Buffalo Wings tasks even though they are not current implementation priorities.

Constrained Least-Squares Patterns

Relevant CodeEli reference:

  • /home/ddmarsha/develop/Code-Eli/include/eli/mutil/opt/least_squares.hpp

Why it matters:

  • it provides a compact reference for equality-constrained least-squares formulations that may reappear in airfoil fitting, continuity-aware fitting, and other geometry reconstruction work.

Bezier Fitting And Approximation Diagnostics

Relevant CodeEli references:

  • /home/ddmarsha/develop/Code-Eli/example/airfoil_fit/airfoil_fit.cpp

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/utility/bezier.hpp

Why they matter:

  • they demonstrate practical constrained fitting workflows,

  • and they include approximation-quality helpers that may inspire future diagnostics or export-quality checks.

Wing-Oriented Skinning And Connection Ideas

Relevant CodeEli references:

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/surface/piecewise_connection_data.hpp

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/surface/piecewise_general_skinning_surface_creator.hpp

Why they matter:

  • they are conceptually close to section-driven wing surface creation,

  • they show one way to organize continuity-aware rib data,

  • and they may be useful algorithm references when Buffalo Wings expands the wing generator toward skinning-style patch construction.

Buffalo Wings caution:

  • these should be treated as algorithm inspiration only,

  • not as a runtime architecture template, because Buffalo Wings uses a different public API model and a Splipy-backed backend strategy.

Geometry Query And Diagnostics Ideas

Relevant CodeEli references:

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/intersect/minimum_distance_curve.hpp

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/intersect/specified_thickness_curve.hpp

  • /home/ddmarsha/develop/Code-Eli/include/eli/geom/curve/equivalent_curves.hpp

Why they matter:

  • they suggest future approaches for geometry queries, inspection tools, fitting diagnostics, and validation helpers.

These are promising for future work, but they are not currently on the critical path compared with CST fitting.

Already-Covered Areas

The following CodeEli topics have already been materially covered by Buffalo Wings and therefore are not current acquisition targets:

  • canonical CST runtime evaluation behavior,

  • canonical CST first- and second-derivative behavior,

  • exact canonical CST-to-Bezier conversion into the spline family,

  • and constrained Bezier degree demotion.

If future work revisits these areas, it should usually focus on verification, diagnostics, or API refinements rather than on importing more baseline functionality from CodeEli.