`pp_slope_bias` — Slope-and-bias prediction correction¶

Group: Signal transforms · C ABI: n4m_domain_adaptation_slope_bias_*

Description¶

Linear slope/bias correction for transferred predictions.

Parameters¶

No constructor parameters.

API and bindings¶

C ABI (ABI 2): n4m_domain_adaptation_slope_bias_create · n4m_domain_adaptation_slope_bias_destroy · n4m_domain_adaptation_slope_bias_fit · n4m_domain_adaptation_slope_bias_is_fitted · n4m_domain_adaptation_slope_bias_transform. Use the linked public header for the exact signature, configuration, and result handles.

Python (verified public re-export):

from n4m.domain_adaptation.standardization import SlopeBiasCorrection

Source signature: SlopeBiasCorrection().

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¶

No single canonical paper defines this two-parameter post-calibration operation. It is ordinary least-squares bias/slope correction, with source code as the exact specification.

Mathematical principle¶

Given paired source predictions \(x\) and target values \(y\), fit estimates \(y=ax+b\) by closed-form OLS. Transform returns \(ax+b\) for new source predictions; it acts on a one-dimensional prediction vector, not on spectra.

Appropriate uses¶

Correcting a stable linear bias and gain error after moving a calibration between instruments or populations.

Limits and validation¶

A constant source prediction makes the slope unidentified. The correction cannot fix nonlinear, heteroscedastic, or wavelength-specific transfer errors and needs paired target values.

Implementation¶

n4m.domain_adaptation.standardization.SlopeBiasCorrection wraps n4m_domain_adaptation_slope_bias_*; the closed-form fit is in cpp/src/c_api/c_api_advanced.cpp.

The ABI-2 implementation is the n4m_domain_adaptation_slope_bias_* lifecycle in libn4m.

Sources and provenance¶

https://github.com/GBeurier/nirs4all-methods/blob/main/cpp/src/c_api/c_api_advanced.cpp#L499-L523

See also: methods index · interactive dashboard

pp_slope_bias — Slope-and-bias prediction correction¶