Depth-Parallel Training of Neural Networks

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for executing depth-parallel training of a neural network. One of the methods includes receiving an input sequence; and at each processing time step in a sequence of processing time steps: processing an input item using a first layer block in a stack of layer blocks to generate a first block output; for each subsequent layer block, processing a block output generated by the preceding layer block at the preceding processing time step to generate a current block output; computing i) a current error in an output item generated by the final layer block and ii) a current gradient of the current error; generating a parameter update for the final layer block; for each particular layer block that is not the final layer block, computing a current gradient for the particular layer block and generating a parameter update.