An energy-based recursive generator (GRAM), shown on Sudoku and on crystals with a target band gap.
Generate a candidate that satisfies a goal, data-efficiently — no millions of labels.
Studied on Sudoku (rule-valid completion) and Crystal (structure with a target band gap).
A strong learned energy — a "ruler" — can drive a recursive generator downhill to good solutions.
Energy is the judge, the generator is the player, pathwise training moves the player the way the judge rewards.
A learned energy is bumpy (traps), so walking straight downhill gets stuck — annealing smooths them away first.
High noise → one broad basin → cool to the global-min "gold" (same idea as IRED).
Verifier AUC reaches 1.0; the generator solves the puzzles it is trained on.
Score-matching loss falls 0.694 → 0.017.
| What | Result | Note |
|---|---|---|
| Verifier AUC (train + held-out) | 1.0 | near-perfect valid / invalid separation |
| Sudoku exact (train) | ≈1.0 | pathwise solves trained puzzles |
| Generator on brand-new puzzles | open | the data-efficiency question |
| Crystal validity · uniqueness | 0.97 · 0.97 | structures are valid and distinct |
| Crystal band-gap error | 2.96 → 1.63 | eV, with conditioning |
Pathwise (direct −∇E) beat sampling-based reward methods in our experiments — so it is the method shown throughout.