doGaussianHidden took priority over doRaoBlackwell when deciding h_states
for the positive-phase gradient, so a Gaussian-hidden RBM always got the
noisy sample (h_probs + randn) for dw/dbh even with doRaoBlackwell set --
ignoring the flag and adding avoidable gradient variance. Standard CD
practice (and pyRBM's cd_gaussian_gaussian) uses the mean for the
weight/bias gradient when Rao-Blackwellizing, regardless of unit type.
Reordered so doRaoBlackwell is checked first (mean, any unit type) and
only samples otherwise, dispatching via the sampleHidden() helper added
in the previous commit so Gaussian/binary hidden units are each sampled
correctly. Behavior-preserving for poet (doRaoBlackwell=true,
doGaussianHidden=false already took the mean branch); only changes
behavior for a Gaussian-hidden RBM trained with doRaoBlackwell enabled.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016K8Gu7Qejd11JbdiHZqYAs
jensandClaude Sonnet 5
4cf5f15555