## Bar Chart: Episode Reward Across Environments & Approaches
### Overview
This is a grouped bar chart comparing the performance of eight different algorithmic approaches across seven distinct reinforcement learning environments. Performance is measured by "Normalised Discounted Reward," a metric scaled between 0.0 and 1.0, where higher values indicate better performance. Each environment cluster contains eight bars, one for each approach, with error bars indicating variability.
### Components/Axes
* **Chart Title:** "Episode Reward Across Environments & Approaches"
* **Y-Axis:**
* **Label:** "Normalised Discounted Reward"
* **Scale:** Linear, from 0.0 to 1.0, with major tick marks at 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0.
* **X-Axis:**
* **Label:** Environment names.
* **Categories (from left to right):** Tiger, RockSample, Empty, Corners, Lava, Rooms, Unlock.
* **Legend:** Positioned at the bottom of the chart, centered. It maps colors to approach names:
* **Grey:** Oracle
* **Dark Blue:** Ours
* **Purple:** Ours (Offline)
* **Magenta:** Ours (Online)
* **Pink:** Direct LLM
* **Salmon/Orange-Red:** Behavior Cloning
* **Orange:** Tabular
* **Yellow:** Random
### Detailed Analysis
Performance is analyzed per environment cluster, moving left to right. Approximate values are estimated from the bar heights relative to the y-axis.
**1. Tiger:**
* **Trend:** Oracle, Ours, and Ours (Online) perform best, near the maximum reward. Performance generally decreases across the remaining approaches.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.95
* Ours (Offline): ~0.92
* Ours (Online): ~0.92
* Direct LLM: ~0.70
* Behavior Cloning: ~0.82
* Tabular: ~0.60
* Random: ~0.52
**2. RockSample:**
* **Trend:** Oracle is highest. "Ours" and "Ours (Online)" show moderate performance. "Ours (Offline)" and "Direct LLM" are notably lower. "Behavior Cloning" is very low.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.75
* Ours (Offline): ~0.60
* Ours (Online): ~0.66
* Direct LLM: ~0.15
* Behavior Cloning: ~0.08
* Tabular: ~0.33
* Random: ~0.0 (near zero)
**3. Empty:**
* **Trend:** A high-performance cluster. Oracle, Ours, Ours (Online), and Tabular all achieve near-maximum reward. Ours (Offline) is slightly lower. Random is the only low-performing approach.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.99
* Ours (Offline): ~0.76
* Ours (Online): ~0.99
* Direct LLM: ~1.0
* Behavior Cloning: ~0.94
* Tabular: ~0.94
* Random: ~0.28
**4. Corners:**
* **Trend:** Oracle is highest. "Ours" and "Ours (Online)" are the next best group. Performance drops significantly for the remaining approaches.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.72
* Ours (Offline): ~0.79
* Ours (Online): ~0.49
* Direct LLM: ~0.50
* Behavior Cloning: ~0.12
* Tabular: ~0.05
* Random: ~0.05
**5. Lava:**
* **Trend:** Oracle is highest. "Ours" is the only other approach with substantial reward. All other approaches perform very poorly, near zero.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.59
* Ours (Offline): ~0.28
* Ours (Online): ~0.18
* Direct LLM: ~0.03
* Behavior Cloning: ~0.05
* Tabular: ~0.03
* Random: ~0.02
**6. Rooms:**
* **Trend:** Oracle is highest. "Ours" shows moderate performance. All other approaches have low to very low rewards.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.68
* Ours (Offline): ~0.39
* Ours (Online): ~0.15
* Direct LLM: ~0.03
* Behavior Cloning: ~0.11
* Tabular: ~0.05
* Random: ~0.02
**7. Unlock:**
* **Trend:** Oracle is highest. "Ours" is the only other approach with a significant reward. All other approaches perform at or near zero.
* **Approximate Values:**
* Oracle: ~1.0
* Ours: ~0.73
* Ours (Offline): ~0.09
* Ours (Online): ~0.01
* Direct LLM: ~0.02
* Behavior Cloning: ~0.0
* Tabular: ~0.0
* Random: ~0.0
### Key Observations
1. **Oracle Dominance:** The "Oracle" approach (grey bar) consistently achieves the maximum normalized reward (~1.0) across all seven environments, serving as an upper-bound benchmark.
2. **"Ours" Consistency:** The "Ours" approach (dark blue) is the most consistent non-oracle performer, maintaining moderate to high rewards in every environment.
3. **Environment Difficulty:** There is a clear gradient in task difficulty. "Empty" appears to be the easiest, with six of eight approaches scoring above 0.75. "Lava," "Rooms," and "Unlock" appear to be the hardest, with only Oracle and "Ours" achieving meaningful rewards.
4. **Approach Variability:** The performance of approaches like "Direct LLM," "Behavior Cloning," and "Tabular" is highly environment-dependent. They perform well in "Empty" but fail in "Lava" or "Unlock."
5. **"Random" Baseline:** The "Random" approach (yellow) performs poorly across all environments, as expected, confirming the tasks require learned policy.
### Interpretation
This chart demonstrates the comparative efficacy of different learning paradigms in varied reinforcement learning settings. The "Oracle" represents an idealized upper bound, likely using perfect model knowledge. The strong, consistent performance of "Ours" suggests it is a robust method that generalizes well across diverse task structures (from navigation in "Empty" to complex manipulation in "Unlock").
The data highlights a key challenge in AI: methods that excel in simple or specific domains (like "Tabular" in "Empty") often fail to transfer to more complex, sparse-reward environments. The significant drop-off for most methods in "Lava," "Rooms," and "Unlock" indicates these environments pose fundamental challenges related to exploration, long-term planning, or partial observability that only the most sophisticated approaches ("Oracle" and "Ours") can handle. The chart argues for the development of generalizable algorithms, as specialized techniques show brittle performance.