aug_spline_smooth — Deterministic natural-cubic spline smoothing¶
Group: Augmentation · C ABI: n4m_augmentation_spline_smoothing_*
Description¶
Spline smoothing augmenter.
Parameters¶
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API and bindings¶
C ABI (ABI 2): n4m_augmentation_spline_smoothing_apply · n4m_augmentation_spline_smoothing_create · n4m_augmentation_spline_smoothing_destroy. Use the linked public header for the exact signature, configuration, and result handles.
Python (verified public re-export):
from n4m.augmentation.splines import SplineSmoothingAugmenter
Source signature: SplineSmoothingAugmenter(rng: Optional[PCG64] = None, seed: int = 0).
R: no current source-verified entry point was found for this catalog method.
MATLAB / Octave: no current source-verified entry point was found for this catalog method.
Explanations¶
Bibliographic source¶
Reinsch (1967), Smoothing by spline functions, Numerische Mathematik 10, 177–183, DOI 10.1007/BF02162161 (https://doi.org/10.1007/BF02162161), provides the classical smoothing-spline basis; the exact fixed smoothing choice here is implementation-specific.
Mathematical principle¶
Fit a cubic smoothing spline independently to each row on the channel grid and evaluate it on that same grid, exactly as scipy.interpolate.UnivariateSpline(x, y, k=3, s=1/p) for \(p\) channels: FITPACK curfit knot selection and smoothing followed by splev. The RNG and seed are accepted by the common wrapper but unused.
Appropriate uses¶
Creating a smoothed view of spectra to reduce high-frequency variation during training.
Limits and validation¶
This operator is deterministic and therefore does not enlarge a dataset with multiple draws. A fixed \(1/p\) smoothing choice may be inappropriate across data scales.
Implementation¶
Python role API n4m.augmentation.splines.SplineSmoothingAugmenter; ABI 2 family n4m_augmentation_spline_smoothing_{create,apply,destroy}.
The ABI-2 implementation is the n4m_augmentation_spline_smoothing_* lifecycle in libn4m.
Sources and provenance¶
https://github.com/GBeurier/nirs4all-methods/blob/main/cpp/src/core/augmentation/splines/spline_smoothing.h; https://doi.org/10.1007/BF02162161
See also: methods index · interactive dashboard