New word vector scheme that learns segments of words rather than unique words... this cuts down on size of vocab and size of soft max at the end? No expensive

New word vector scheme that learns segments of words rather than unique words... this cuts down on size of vocab and size of soft max at the end? No expensive attention mechanism? This cuts down on number of parameters needed quite a bit, especially when sequences get very long. I know what an RNN is but what is a QRNN? Will need to read this more closely. I thought the key research direction now was improving the efficiency of the self attention block but maybe not.