HasRegression
Result trait for regression error metrics. Extends HasSampleVariance because R² is defined as 1 - sse/sst, and sst is the variance-family sum of squared deviations from the mean.
Implemented by com.eignex.kumulant.stat.regression.glm.LinearRegressionResult. Consumers asking for HasRegression don't care which underlying regressor produced the snapshot; SGD, Bayesian, diagonal, or hierarchical all surface the same sse / mse / rmse / rSquared metrics.
Under non-identity GLMs (Link.Logit, Link.Log) sse carries the per-link deviance, not the classical SSE, and rSquared is not the usual Gaussian R². Each GLM result documents its sse interpretation.
Inheritors
Properties
Mean squared error: sse / totalWeights. Zero on an empty stream.
Unbiased sample standard deviation: sqrt([sampleVariance]).
Unbiased sample variance: [sst] / ([totalWeights] - 1). Zero when totalWeights <= 1.
Cumulative weight of observations folded into this result.
mse
Mean squared error: sse / totalWeights. Zero on an empty stream.