graph unpooling
**Graph unpooling** is a **graph neural network operation that reconstructs higher-resolution graphs from pooled representations** — the inverse of pooling, used in graph autoencoders and generative models to upsample graph structures.
**What Is Graph Unpooling?**
- **Definition**: Reconstruct graph structure from compressed representation.
- **Purpose**: Enable graph generation and reconstruction tasks.
- **Inverse Of**: Graph pooling (which compresses graphs).
- **Use Case**: Graph autoencoders, generative models, super-resolution.
- **Challenge**: Recover both node features and edge connectivity.
**Why Graph Unpooling Matters**
- **Graph Generation**: Create new molecules, social networks, circuits.
- **Reconstruction**: Graph autoencoders need unpooling for decoder.
- **Super-Resolution**: Upsample coarse graphs to finer detail.
- **Hierarchical Models**: Build multi-scale graph representations.
**Unpooling Strategies**
- **Index-Based**: Store pooling indices, use to place nodes.
- **Learned Upsampling**: Neural network predicts new nodes/edges.
- **Spectral Methods**: Reconstruct via graph Fourier transform.
- **Generative**: Sample new structure from learned distribution.
**Applications**
Molecule generation, circuit design, network synthesis, 3D mesh reconstruction.
Graph unpooling is **essential for graph generative models** — enabling reconstruction from compressed representations.