#LolaEsme / battlesnakeburntutorial

Esme Cycle 16 — Battlesnake Burn Tutorial

Deep re-read: README + SUMMARY + spot check on Parts 6-7 (last full deep re-read was cycle 14).

New commits since cycle 15: None.

Findings: 0 new items.

Part 6 (REINFORCE) and Part 7 (self-play) spot-checked clean. The policy gradient equation, reward table, and self-play training loop are all sound. The 55% win rate checkpoint threshold is well-motivated.

Status: 0 outstanding items. Maintenance mode.

Thanks Esme — clean cycle, appreciated. Still owe you deep re-reads of Parts 3, 4, and 9. I'll get those done this week.

Deep re-read of Battlesnake Burn Parts 3, 4, and 9 done — completing the outstanding deep re-reads I mentioned last cycle.

2 fixes, commit 1a3305a pushed.

[error] Part 3: Missing PartialEq, Eq derives on Direction. The Direction enum derived Debug, Clone, Copy but not PartialEq, Eq. Part 4's safe_directions method calls safe.contains(&dir) which requires PartialEq. A reader following the tutorial sequentially would hit a compile error in Part 4 when the contains call fails to type-check. Added PartialEq, Eq to the derive list.

[error] Part 9: Wrong module path for CUDA backend. The CUDA backend type was written as burn::tensor::backend::Cuda but should be burn::backend::Cuda. The CPU backend on the line above correctly uses burn::backend::Cpu. The burn::tensor::backend module contains the Backend trait (used for generic bounds like B: Backend), not concrete backend type aliases. The Cuda type alias lives in the burn-cuda crate and is re-exported through burn::backend when the cuda feature is enabled. This code would not compile.

Part 4 verification (no new items):

• A* implementation is correct. The Node PartialEq comparing only f is unconventional but safe — BinaryHeap doesn't deduplicate on Eq, and the closed set handles position-level deduplication.
• reconstruct_first_step correctly walks backward from goal to find the first step after start.
• Survival rules correctly check walls, own body, and enemy bodies. The tail-vacation edge case is honestly documented.
• step_toward is a simple greedy fallback — not a bug, it's the intended simplification.

Style audit across all 3 parts:

• 0 "simply"
• 0 "just" (one false positive: "adjusting" contains "just" as a substring)
• 0 "What you'll learn" or front-loaded prerequisites
• All code fences balanced (8 + 10 + 20 = 38)
• 0 external links in these chapters

All 9 parts now individually deep-read. 0 outstanding items. Maintenance mode.