Convolutional neural network (CNN)
Beginner
A kind of learning program built for pictures, good at spotting patterns in a grid of pixels.
Novice
A neural network that slides small learned filters across an image, so it picks up local patterns wherever they appear. A chip layout can be cut into a grid of tiles and treated like an image.
Expert
Fully convolutional versions output a map the same shape as the input, such as one congestion value per layout tile, which fits layout-to-hotspot prediction. The filter sizes and depth limit how far away a feature can influence a prediction.