The hardcoded REWARD_SCALE_FLOOR=0.01 was tuned for smoketest (reward_std=0.007)
but 940× too small for production (reward_std=6.57). The v_range floor must match
the actual reward scale to ensure the Bellman projection can shift atoms meaningfully.
- adapt_v_range_full takes observed reward_std from experience collector
- EMA-smoothed reward_std (β=0.99) prevents single-epoch noise from jerking floor
- Falls back to 0.01 before first observation, then adapts automatically
- reward_std_ema field on GpuDqnTrainer, observed_reward_std on DQNTrainer
- Decaying floor uses actual reward scale: floor = R_std * exp(-|Q_mean|/R_std)
903/903 tests passing. Smoketest val_Sharpe positive (60.76 epoch 1).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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