class_docstr: Observation model for beat tracking with a HMM.
  
  Parameters
  ----------
  state_space : :class:`BeatStateSpace` instance
      BeatStateSpace instance.
  observation_lambda : int
      Split one beat period into `observation_lambda` parts, the first
      representing beat states and the remaining non-beat states.
  
  References
  ----------
  .. [1] Sebastian Böck, Florian Krebs and Gerhard Widmer,
         "A Multi-Model Approach to Beat Tracking Considering Heterogeneous
         Music Styles",
         Proceedings of the 15th International Society for Music Information
         Retrieval Conference (ISMIR), 2014.
class_docstr_tok: ["Observation","model","for","beat","tracking","with","a","HMM",".","Parameters","--","--","--","--","--","state_space",":",":","class",":","`","BeatStateSpace","`","instance","BeatStateSpace","instance",".","observation_lambda",":","int","Split","one","beat","period","into","`","observation_lambda","`","parts",",","the","first","representing","beat","states","and","the","remaining","non-beat","states",".","References","--","--","--","--","--","..","[","1","]","Sebastian","B\u00f6ck",",","Florian","Krebs","and","Gerhard","Widmer",",","``","A","Multi-Model","Approach","to","Beat","Tracking","Considering","Heterogeneous","Music","Styles","''",",","Proceedings","of","the","15th","International","Society","for","Music","Information","Retrieval","Conference","(","ISMIR",")",",","2014","."]
code: def __init__(self, state_space, observation_lambda):
      self.observation_lambda = observation_lambda
      # compute observation pointers
      # always point to the non-beat densities
      pointers = np.zeros(state_space.num_states, dtype=np.uint32)
      # unless they are in the beat range of the state space
      border = 1.0 / observation_lambda
      pointers[state_space.state_positions < border] = 1
      # instantiate a ObservationModel with the pointers
      super(RNNBeatTrackingObservationModel, self).__init__(pointers)
  
imports: from __future__ import absolute_import, division, print_function
  import numpy
  from madmom.ml.hmm import ObservationModel, TransitionModel
label_desc: Use image node_id 1 to create a new RNNBeatTrackingObservationModel object from inherited base classes: ObservationModel with example: obj = RNNBeatTrackingObservationModel(state_space, observation_lambda)