MambaRecurrence reconstructs MambaBlock's selective-scan as an explicit
step(state, x_t) -> (state', y_t) recurrence over host f32 weights, with the
recurrent state (h, conv-ring) carried between steps. This is the substrate the
SMT memory updater is behaviorally cloned on (E3b) — no BPTT, one step at a time.
Dimensions are derived from the persisted tensor shapes, so mamba.rs is left
untouched (it is near the 1250-LOC cap). silu/softplus are byte-identical copies
of the forward's.
Equivalence pin (the plan's highest-risk item): stepping a window one token at a
time from a zero state reproduces the full-sequence forward EXACTLY —
max_abs_diff = 0.0 (bit-identical), on an active_block with wide Delta so the
scan genuinely drives the output. Plus a fresh-state determinism test.
clippy(-D warnings) + fmt clean on the new module and test.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
