MATLAB TCL parity inventory

A function-level comparison of pytcl 2.0.0 against the U.S. Naval Research Laboratory’s Tracker Component Library (commit 593ce51), produced by walking every directory of the MATLAB repository rather than by asserting a percentage.

Why this document exists

Earlier documentation claimed “full feature parity” and “100% MATLAB parity”. Those claims were scoped to a tier-1/tier-2 component list that was never published alongside them, and one of their checkmarks — NRLMSISE-00 — proved to be a placeholder shipped under the model’s name (gh-79). This inventory replaces assertion with enumeration.

Method

The MATLAB public surface was counted under MATLAB’s actual visibility rules: a regular .m file exposes exactly its first function (later declarations are file-local subfunctions), and classdef files expose their methods except those in Access = private blocks. Third-party code, sample code and compiled artifacts are excluded. That yields 2,549 public names across 1,843 files — against 1,899 public names in pytcl.

Automated name matching is a lower bound only: MATLAB ships one file per variant where pytcl uses a keyword argument, and the port renamed systematically (KalmanUpdate → kf_update). The verdicts below come from reading each area’s function list against pytcl’s modules.

Summary

pytcl ports the core tracking workflow comprehensively and validates it against independent references, but the MATLAB library’s full surface is substantially broader. By function count, coverage is roughly a third of the MATLAB public surface. By workflow — filter, associate, track, evaluate, in Earth-referenced coordinates — coverage is near-complete, and in several places pytcl exceeds the original (OSPA/MOT metrics, ionosphere models, R-trees and cover trees, min-cost flow, SQL/HDF5 track storage, GPU backends).

MATLAB area	Public	Coverage	Notes
Dynamic_Estimation	113	Core strong	KF/EKF/UKF/CKF, square-root and UD forms, SRIF, information filter, H-infinity, IMM, particle filters, RBPF, RTS/two-filter/fixed-lag/ fixed-interval smoothers all ported. Missing: EnKF, ESRIF, quasi-Monte-Carlo Kalman variants, BLUE polar/spherical measurement updates, progressive Gaussian update, pure-propagation filter, reduced-state filters, batch least-squares estimators, PCRLB/Riccati analysis tools.
Dynamic_Models	62	Partial	CV/CA, coordinated turn (2D/3D/polar), Singer, Gauss-Markov F and Q matrices ported. Missing: weave/spiral maneuver models, flat-to-curved-Earth dynamics, geodesic Brownian motion, trajectory generators with constrained endpoints, process-noise suggestion tooling.
Assignment_Algorithms	45	Core strong	2D assignment (Hungarian, auction, Murty k-best), 3D assignment, JPDA with gating, min-cost flow all ported and oracle-validated. Missing: bottleneck assignment, knapsack, transportation problem, stable-matching family, missed-detection LR matrix builders, assignment-probability calculators beyond JPDA.
Coordinate_Systems	331	Partial	Cartesian/spherical/polar/geodetic/ENU/NED/SEZ conversions, rotations, quaternions, r-u-v (range plus direction cosines, cart2ruv/ ruv2cart), UTM and standard projections ported and validated to sub-mm against pyproj/EPSG. Missing: the angle-only direction- cosine UV measurement system (spher2Uv/uv2Spher-style conversions, u-v-w unit vectors, and their Jacobians – the natural measurement space of a planar phased array; distinct from the ported r-u-v triple), most of the 65-function time suite (pytcl covers UTC/TAI/TT/GPS and Julian dates; TDB/TCB/TCG, Besselian epochs, sidereal local time variants absent), the 30 measurement Jacobians and 14 Hessians as standalone functions, exotic projections (bipolar, gnomonic, azimuthal-equidistant families), ellipsoidal-harmonic coordinates, RF transform-parameter estimation.
Mathematical_Functions	1,506	Selective	The largest area and the largest gap, though much of it is generic numerics rather than tracking. Ported well: signal processing (CFAR family, matched filtering, STFT/CWT/DWT), core statistics (12 distribution classes vs MATLAB’s ~40), interpolation, basic matrix operations, special functions. Thin or absent: the cubature-point library (~148 files — a signature strength of the MATLAB TCL; pytcl has Gauss-Hermite and spherical cubature only), combinatorics (113 vs 18), polynomials (55; no pytcl counterpart), geometry beyond basics (81), continuous optimization (37), specific integrals/derivatives, graph algorithms, accurate-arithmetic helpers.
Astronomical_Code	28	Partial	SGP4 (validated against the official library), Kepler propagation, orbital elements, Lambert solvers, JPL ephemerides via jplephem. Missing: Hipparcos catalog access, aberration and light-deflection corrections, EOP acquisition, angles-only initial orbit determination, two-point velocity determination, equinoctial Kepler solver.
Atmosphere_and_Refraction	34	Weak	U.S. Standard Atmosphere 1976/ISA validated; barometric thermosphere with documented limits (gh-79). Missing: the entire refraction suite (astronomical refraction add/remove, standard refraction ray tracing, refractivity models), all humidity conversions, Jacchia model, NRLMSISE-00 proper. pytcl adds ionosphere models (Klobuchar, TEC) that the MATLAB area lacks.
Gravity	14	Good	EGM coefficient loading, geoid height, normal gravity, tide offsets (solid/pole/ocean) ported. Missing: lunar gravity coefficients, polar-motion/drift coefficient adjustments, ellipsoidal parameter conversions.
Magnetism	12	Split	Coefficient loading and field evaluation for WMM/IGRF/EMM ported and validated to sub-nT. Missing: the coordinate-system half — apex and quasi-dipole coordinates, centered-dipole transforms, magnetic-heading conversions, field-line tracing.
Navigation	21	Good	Direct/indirect geodesic, great-circle and rhumb problems ported, validated against GeographicLib; rhumb intersection is ported as rhumb_intersect and great-circle TDOA as great_circle_tdoa_loc. Missing: geodesic and great-circle intersections, surface angles.
Static_Estimation	11	Divergent	The name overlaps; the content mostly does not. MATLAB’s area is target localization: TDOA, Doppler-only init, range-rate-only, direction-only static estimators — almost all absent from pytcl. pytcl’s static_estimation instead ports the general estimators (OLS/TLS/RANSAC/robust/RLS/MLE) that MATLAB keeps elsewhere.
Clustering_and_Mixture_Reduction	14	Good	Runnalls and West mixture reduction, k-means(++), EM clustering ported; pytcl adds DBSCAN and hierarchical clustering. Missing: ISE-based reduction and its gradients, brute-force reduction, windowed grid centroiding.
Container_Classes	265	Different emphasis	k-d tree and metric tree ported (as KDTree/BallTree/VPTree), ClusterSet ported; pytcl adds R-trees, cover trees and the whole track/measurement container layer. Missing: AVL tree, binary heaps, disjoint sets, linked lists, interval class, B-spline class — largely idiomatic-Python non-goals, but absent nonetheless.
Performance_Evaluation	12	Split	NEES (with confidence bounds), RMSE ported; pytcl adds the standard OSPA metric and CLEAR-MOT metrics. Missing: MATLAB’s MOSPA/MMOSPA family (calcMOSPAError, MMOSPA2Tar2D — a related but distinct OSPA-family capability), AEE/GAE, jitter, MERF, non-credibility index.
Terrain	3	Good	Earth2014 loading ported (plus GEBCO, which MATLAB lacks); solid-tide shift ported. EGM2008 terrain coefficients not ported.
Misc	52	Mostly N/A	Bit manipulation, MATLAB plotting, file utilities — superseded by numpy/matplotlib/stdlib. Substantive absences: GSHHG coastline data access and pointIsOnLand.
Transponders	3	Absent	AIS/NMEA decoding not ported.
Scheduling	4	Absent	Interval scheduling algorithms not ported.
Physical_Values	14	Partial	Physical constants ported. Radar bands, water permittivity and reflection-coefficient models absent.

What pytcl has that the MATLAB library does not

The comparison runs both ways. pytcl adds: the standard OSPA metric and CLEAR-MOT evaluation, ionospheric delay models, R-trees and cover trees, DBSCAN and hierarchical clustering, min-cost-flow assignment, SQL and HDF5 track storage with migration tooling, dual-backend GPU acceleration, and a validation suite of 6,000+ tests with 27 files checking against independent references — the MATLAB library distributes no test suite at all.

Honest bottom line

The defensible claim is not “full feature parity”. It is: the core tracking workflow is ported, oracle-validated, and in places extended; the MATLAB library’s long tail — its cubature collection, refraction suite, time-scale zoo, localization estimators and specialized coordinate systems — is substantially unported, at roughly a third of the full public surface by function count. Areas above marked Absent, Weak or Divergent are the honest priority list for anyone who needs them.