SRAE: evidence-screened empirical-Bayes additive models

SRAE fits an interpretable order-two functional-ANOVA model

\[f(\mathbf{x}) \;=\; \beta_0 \;+\; \sum_{j} f_j(x_j) \;+\; \sum_{(j,k)\,\in\,\mathcal{S}} f_{jk}(x_j, x_k)\]

with penalized-spline main effects and a small set of automatically screened pairwise tensor interactions. The roughness precisions \(\lambda_j\), the null-space precisions \(\kappa_j\), and (for Gaussian regression) the residual variance \(\sigma^2\) are estimated from a marginal-likelihood objective rather than by cross-validated grid search.

Every fitted component is a plottable one- or two-dimensional function with a pointwise credible band, and model capacity is reported as effective degrees of freedom per component.

Note

Basis resolution, candidate-pair caps, screening thresholds, and maximum interaction counts remain structural settings chosen by the user. Only the continuous shrinkage parameters are estimated internally. See Scope and limitations.

Estimator overview

Eight estimators span a \(2 \times 2\) design over two independent axes, crossed with the regression / classification task.

Regularization

Hyperprior

Regression

Classification

Type-II MLE

point estimate

SRAERegressor

SRAEClassifier

pooled stack

point estimate

SRAERegressorPooled

SRAEClassifierPooled

Type-II MLE

integrated

SRAERegressorSI

SRAEClassifierSI

pooled stack

integrated

SRAERegressorSIPooled

SRAEClassifierSIPooled

The regularization axis selects how the block hyperparameters \((\lambda_j, \kappa_j)\) are estimated; the hyperprior axis selects whether those hyperparameters are used as a point estimate or integrated over. See Estimator variants for when each is appropriate.

Scope and limitations

  • The model is restricted to smooth main effects and selected pairwise interactions; no three-way or higher terms.

  • Interaction discovery is greedy and conditional on the main-effect fit. The screening score is a conditional residual marginal likelihood, not an exact Bayes factor for the full model — especially under the logistic likelihood.

  • The product-correlation pre-ranking used when the candidate set exceeds max_screen_pairs can miss interactions that are symmetric, masked, or poorly represented by a centered product.

  • Uncertainty summaries condition on the estimated hyperparameters, the selected interaction set, and the fixed basis. They do not propagate interaction-selection uncertainty.

  • Multiclass classification is one-vs-rest, not a jointly estimated multinomial model; the row-normalized probabilities are not guaranteed calibrated.

  • The logistic path is approximate (Laplace); evidence monotonicity is not guaranteed by the Gaussian EM argument.

  • The implementation uses dense linear algebra and does not accept sparse input, missing values, or non-numeric columns.

Indices