---
license: mit
tags:
- pytorch
- safetensors
- threshold-logic
- neuromorphic
---

# threshold-xor4

4-input XOR gate. Cascade of three standard XOR circuits (OR + NAND + AND).

## Architecture

```
a  b       c       d
│  │       │       │
└──┴──┐    │       │
      ▼    │       │
   ┌─────┐ │       │
   │ XOR │ │       │
   └──┬──┘ │       │
      └──┬─┘       │
         ▼         │
      ┌─────┐      │
      │ XOR │      │
      └──┬──┘      │
         └────┬────┘
              ▼
           ┌─────┐
           │ XOR │
           └──┬──┘
              ▼
        XOR4(a,b,c,d)
```

Each XOR uses the standard OR + NAND + AND structure:
- OR: w=[1,1], b=-1 (magnitude 3)
- NAND: w=[-1,-1], b=1 (magnitude 3)
- AND: w=[1,1], b=-2 (magnitude 4)

## Parameters

| | |
|---|---|
| Neurons | 9 |
| Layers | 6 |
| Parameters | 27 |
| Magnitude | 30 |

## Optimized Version

See `threshold-xor4-mag21` for a 30% magnitude reduction using optimized XOR blocks.

## Usage

```python
from safetensors.torch import load_file

w = load_file('model.safetensors')
# See model.py for implementation
```

## License

MIT