MMI-estimation, fixed a bug in covariance gradient
MMI-estimation, fixed a bug in covariance gradient

phsmit/AaltoASR,lingsoft/AaltoASR,lingsoft/AaltoASR,phsmit/AaltoASR,aalto-speech/AaltoASR,aalto-speech/AaltoASR,lingsoft/AaltoASR,aalto-speech/AaltoASR,aalto-speech/AaltoASR,kkleino/AaltoASR,phsmit/AaltoASR,aalto-speech/AaltoASR,lingsoft/AaltoASR,kkleino/AaltoASR,kkleino/AaltoASR,kkleino/AaltoASR,lingsoft/AaltoASR,phsmit/AaltoASR,kkleino/AaltoASR