# Technical Document Extraction: Neural Network Architecture with Rational Units
## Diagram Overview
The image depicts a neural network architecture with two processing blocks (Update and Head) connected to a readout. The network incorporates specialized Rational 1D (R₁D) and Sparse Rational 2D (R₂D) units with explicit mathematical formulations.
---
## Component Breakdown
### 1. Network Structure
**Blocks:**
- **Block 1 (Update):**
- Contains residual connections (`x ← Norm(x + Res)`)
- Processes input features `x₁, x₂, ..., xₙ`
- **Block 2 (Head):**
- Final processing layer before readout
- Contains multiple R₁D and R₂D units
**Readout:**
- Final output `y` computed as cumulative sum of block outputs
### 2. Rational 1D Unit (R₁D)
**Mathematical Definition:**
```
R(x) = P(x) / [1 + softplus(Q(x))]
y = x + α[R(x) - x]
```
**Graphical Representation:**
- 2D plot showing sigmoidal-like activation function
- X-axis: Input `x`
- Y-axis: Output `R(x)`
- Key characteristic: Smooth transition from linear to saturated behavior
### 3. Sparse Rational 2D Unit (R₂D)
**Mathematical Definition:**
```
R(xᵢ, xⱼ) = P(xᵢ, xⱼ) / [1 + softplus(Q(xᵢ, xⱼ))]
y = base + β[R(xᵢ, xⱼ) - base]
base = (xᵢ + xⱼ)/2
```
**Graphical Representation:**
- 3D surface plot showing interaction between two inputs
- X-axis: `xᵢ`
- Y-axis: `xⱼ`
- Z-axis: Output `R(xᵢ, xⱼ)`
- Color gradient indicates activation intensity
- Scatter-add operation combines with base value
---
## Key Equations
1. **Rational 1D Unit:**
```
R(x) = P(x) / [1 + softplus(Q(x))]
y = x + α[R(x) - x]
```
2. **Sparse Rational 2D Unit:**
```
R(xᵢ, xⱼ) = P(xᵢ, xⱼ) / [1 + softplus(Q(xᵢ, xⱼ))]
y = base + β[R(xᵢ, xⱼ) - base]
base = (xᵢ + xⱼ)/2
```
3. **Update Mechanism:**
```
x ← Norm(x + Res)
```
---
## Spatial Analysis
- **Legend Position:** Not explicitly shown in diagram
- **Color Coding:**
- Blue nodes: Network units
- Yellow blocks: Rational units
- Green node: Final readout
- **Flow Direction:**
- Bottom-up processing from input features to readout
- Residual connections maintain information flow
---
## Trend Verification
1. **R₁D Unit:**
- Visual trend: Output increases with input until saturation
- Confirmed by sigmoidal-like curve in 2D plot
2. **R₂D Unit:**
- Visual trend: Bilateral interaction between inputs creates peak activation
- Confirmed by 3D surface plot showing maximum at mid-range inputs
---
## Critical Observations
1. **Residual Connections:**
- Enable gradient flow through deep network
- Maintain original input information
2. **Rational Units:**
- Combine linear and nonlinear processing
- Softplus in denominator prevents division by zero
3. **Sparse 2D Interaction:**
- Explicit pairwise feature combination
- Base value ensures symmetry in input space
---
## Missing Elements
- No explicit data table present
- No secondary language detected (all text in English)
- No axis markers beyond those described in component graphs
This extraction provides complete technical specifications for implementing the described neural network architecture with Rational units.