tweaks to SFA learner
tweaks to SFA learner

BIDData/BIDMach,jamesjia94/BIDMach,BIDData/BIDMach,jamesjia94/BIDMach,jamesjia94/BIDMach,BIDData/BIDMach,jamesjia94/BIDMach,BIDData/BIDMach,jamesjia94/BIDMach,BIDData/BIDMach,jamesjia94/BIDMach,BIDData/BIDMach