pp_kubelka_munk — Kubelka Munk

Group: Preprocessing · Binding: n4m.sklearn.KubelkaMunk · C ABI: n4m_pp_kubelka_munk_*

Description

KM = (1 - R)^2 / (2 R), with R guarded by epsilon.

Parameters

Name	Type	Default
is_percent	bool	False
epsilon	float	1e-10

Explanations

Bibliographic source

Standard spectroscopic operator — see the nirs4all preprocessing / augmentation handbook and the cited literature within the binding docstring.

Mathematical principle

KM = (1 - R)^2 / (2 R), with R guarded by epsilon.

Implementation

C ABI n4m_pp_kubelka_munk_* in libn4m (create / apply / destroy lifecycle), wrapped by n4m.sklearn.KubelkaMunk. The same numerical kernel backs every language binding.

Usage

from n4m.sklearn import KubelkaMunk
op = KubelkaMunk()
X_transformed = op.fit_transform(X)

Benchmarks

Adaptive wall-clock per cell measured against full_matrix.csv. Only backends that implement this method are listed; libraries without the method are omitted.

Verdict  ·  ✓ ref / ≈ ref / ~ shape mark a reference-gate pass at strict / relaxed / qualitative tolerance  ·  ✓ bind = pls4all binding agrees with the C++ baseline  ·  ⇄ cross-check = documented by-design selector/RNG/model, noncanonical API/facade convention, or secondary oracle  ·  ✗ divergent  ·  ⚠ error  ·  — not run. The fastest backend per column is marked 🏆.

Reference gate: strict — numeric equivalence (rmse_rel_tol ≤ 1e-12).

1 thread

Backend	Parity	50×250 (ms)	250×50 (ms)
C++ native · libn4m
pls4all.cpp.blas	✓ ref	0.01 ms🏆	0.03 ms
pls4all.cpp.blas+omp	✓ ref	0.03 ms	0.03 ms
pls4all.cpp.omp	✓ ref	0.03 ms	0.02 ms
pls4all.cpp.ref	✓ ref	0.01 ms	0.01 ms🏆
Python · pls4all
pls4all.python	✓ bind	0.01 ms	0.01 ms
pls4all.sklearn	✓ bind	0.01 ms	0.01 ms
Python · external
nirs4all	source	0.03 ms	0.03 ms
ref.python_numpy	source	—	—

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See also: methods index · interactive dashboard