Lasagne is a lightweight library to build and train neural networks in Theano. Its main features are: Supports feed-forward networks such as Convolutional Neural Networks (CNNs), recurrent networks including Long Short-Term Memory (LSTM), and any combination thereof. Allows architectures of multiple inputs and multiple outputs, including auxiliary classifiers. Many optimization methods including Nesterov momentum, RMSprop and ADAM. Freely definable cost function and no need to derive gradients due to Theano’s symbolic differentiation. Transparent support of CPUs and GPUs due to Theano’s expression compiler