MTNN, which stands for Multilevel Neural Networks, is a PyTorch-based library for the application of multilevel algorithms to the training of neural networks. The algorithms behind MTNN mathematically work whenever the neural network can be decomposed into a set of operational subsets such that each subset consists of a set of neurons, channels, or other similar operational units. In this case, pairs of neurons (or channels or other operational units) can be matched up and restricted into a coarse network. Requires Python 3.6 or newer.