n vector of data - N vectors of dim p (X is Nxp)
  radius      - the bandwidth (radius of the window)
  rate        - [] gradient descent proportionality factor in (0,1]
  maxIter     - [] maximum number of iterations
  minCsize    - [] min cluster size (smaller clusters get eliminated)
  blur        - [] if blur then at each iter data is 'blurred', ie the
                original data points move (can cause 'incorrect' results)

 OUTPUTS
  IDX         - cluster membership [see kmeans2.m]
  M           - cl