aug_local_mixup — Nearest-neighbor constrained mixup¶
Group: Augmentation · C ABI: n4m_augmentation_local_mixup_*
Description¶
Neighbor-constrained mixup augmentation.
Parameters¶
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API and bindings¶
C ABI (ABI 2): n4m_augmentation_local_mixup_apply · n4m_augmentation_local_mixup_create · n4m_augmentation_local_mixup_destroy. Use the linked public header for the exact signature, configuration, and result handles.
Python (verified public re-export):
from n4m.augmentation.mixup import LocalMixupAugmenter
Source signature: LocalMixupAugmenter(alpha: float = 0.2, k_neighbors: int = 5, 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¶
This is an internal local variant of Zhang et al.’s mixup (2018), arXiv:1710.09412 (https://arxiv.org/abs/1710.09412); no separate canonical paper defines the specific k-nearest-neighbor rule used here.
Mathematical principle¶
Compute exact Euclidean neighbors in X. For each row choose uniformly among its k_neighbors nearest non-self rows, draw \(\lambda_i\sim\operatorname{Beta}(\alpha,\alpha)\), and form \(X'_i=\lambda_iX_i+(1-\lambda_i)X_{n(i)}\).
Appropriate uses¶
Interpolating locally within a spectral manifold while avoiding arbitrary distant pairs.
Limits and validation¶
Euclidean distance is scale- and preprocessing-dependent. Neighborhood search is quadratic in sample count, and, as for global mixup, y is not returned or mixed.
Implementation¶
Python role API n4m.augmentation.mixup.LocalMixupAugmenter; ABI 2 family n4m_augmentation_local_mixup_{create,apply,destroy}.
The ABI-2 implementation is the n4m_augmentation_local_mixup_* lifecycle in libn4m.
Sources and provenance¶
https://github.com/GBeurier/nirs4all-methods/blob/main/cpp/src/core/augmentation/mixup/local_mixup.h; https://arxiv.org/abs/1710.09412
See also: methods index · interactive dashboard