SirStone
254c7dc997
- Gun harness: virtual bullet tracker, rolling fitness, auto-selector - Guns: head-on, linear (extrapolation), circular (integrated formula), tsetlin machine (learning) - Movement: phantom meteor gravity engine (danger histograms, phantom bullets, fire detection) - Radar: harness + radar_lock adapter - Color-coded modules: turret/bullet color per gun, body per movement, scan per radar - Beats Target, SpinBot, Crazy, TrackFire in 10-round battles
93 lines
4.5 KiB
Markdown
93 lines
4.5 KiB
Markdown
# BNNBot Research Brief
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## Problem
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Predict enemy future position in Robocode Tank Royale to aim bullets accurately. The prediction must happen online (during battle), without pre-training.
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## Hard Constraints
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- NO supervised learning (no labeled input→output training pairs)
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- NO gradient descent (no derivatives, no surrogate gradients, no STE)
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- Online learning only — must learn and improve during a single battle
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- Computational budget: ~1ms per tick
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- Binary-friendly (690-bit input encoding already exists)
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## Allowed
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- Backpropagation of SIGNALS (non-gradient information flowing backward through layers)
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- Reinforcement learning (reward signal available from wave hit system)
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- Self-supervised learning
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- Unsupervised learning
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- Network structure modification during runtime
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## Current Architecture
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### Input Engineering (binary_encoding.nim)
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- 690-bit binary vector: 10 frames × 69 bits
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- Per frame: bearing sin/cos (16b), distance (7b), velocity (5b), heading sin/cos (16b), enemy X/Y position (14b), enemy energy (11b)
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- Gray-coded for Hamming distance smoothness
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- Temporal window: 10 most recent radar scans
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### Feedback System (wave system in BNNBot.nim)
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- Every tick: 10 circular waves spawned at bot position
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- Powers: 0.1 to 3.0 (10 levels), speeds: 19.7 to 11.0 px/tick
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- When wave radius reaches enemy: records enemy state as 69-bit frame
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- Provides ground truth: "if you fired at power X, the enemy would be HERE when the bullet arrives"
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- ~95.6% hit rate in testing
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### Current Predictor (predictor.nim)
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- Linear extrapolation: predicted = current_pos + velocity * ticks_to_arrival
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- Hebbian residual table: 8 heading sectors × 3 distance bands = 24 cells
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- Each cell stores (correction_x, correction_y), updated online with lr=0.2
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- Backtest results: 14-21% MAE reduction over pure linear extrapolation
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- Converges within one battle (MAE 14.85 → 2.62, first 50 vs last 50 rows)
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## Key Findings
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### Data Analysis (analysis/report.txt)
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- Enemy movement is 97.8% constant-velocity straight lines
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- Acceleration is negligible (std 0.25-0.49 px/tick²)
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- Heading is very stable across 10-frame windows
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- Linear extrapolation MAE: 15-27px (1.5-2.7% of arena)
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- Distance to enemy is the main error driver
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- Scalar velocity alone is weak predictor (r=0.15); directional velocity from frame deltas is strong
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### Backtest Results (analysis/backtest_report.txt)
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- P1 (linear): MAE 8.1-18.7 encoded units
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- P2 (weighted 4-frame): ~8% improvement, trivial cost
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- P3 (linear + Hebbian residual): 14-21% improvement, converges fast
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- Most residual table cells stay empty — only ~10/24 activate
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### Encoding Insights
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- sin/cos angle encoding avoids wraparound discontinuity — worth the extra bits
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- Enemy X/Y position partially redundant with bearing+distance (encodes absolute position)
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- Wall distance → XY% compression saved 140 bits losslessly
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- Self-state removed (not needed for aiming)
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## What We've Tried
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1. ✅ Input engineering with Gray coding and temporal window — works well
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2. ✅ Linear extrapolation — strong baseline, 15-27px error
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3. ✅ Hebbian residual table — learns online, 14-21% improvement
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4. ❌ Pure XOR layer stacking — collapses (associative, no non-linearity)
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5. ❌ XOR + AND layers — AND with fixed mask is still linear over GF(2)
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6. ✅ XOR + popcount + threshold = valid binary neuron (non-linear)
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## Open Questions
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1. Can we go deeper than the current shallow predictor while respecting the constraints?
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2. What non-gradient learning rules can train multi-layer binary networks?
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3. Can the temporal structure (10 frames) be exploited by the network architecture?
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4. Is there a way to do credit assignment through depth without gradients?
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5. Can the wave hit system provide richer learning signal than just miss distance?
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## Architecture Philosophy
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- Input engineering IS the feature hierarchy (handcrafted, domain-informed)
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- Current approach is essentially reservoir computing: rich fixed features → simple learnable readout
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- Question: can we do better with a learnable feature extractor, or is the handcrafted one already near-optimal?
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## Files
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- `src/BNNBot.nim` — main bot, wave system, integration
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- `src/binary_encoding.nim` — 690-bit input encoding
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- `src/predictor.nim` — linear extrapolation + Hebbian residual table
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- `analysis/correlations.py` — data analysis script
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- `analysis/backtest.py` — predictor comparison script
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- `analysis/report.txt` — correlation analysis results
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- `analysis/backtest_report.txt` — predictor backtest results
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- `data/` — CSV battle logs (enabled via BNNBOT_CSV=1)
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