'Reports convergence to :data:`sys.stderr`.
The output consists of three columns: iteration number, log
probability of the data at the current iteration and convergence
rate.  At the first iteration convergence rate is unknown and
is thus denoted by NaN.
Parameters
logprob : float
The log probability of the data as computed by EM algorithm
in the current iteration.'

def report(self, logprob):

    if self.verbose:
        delta = ((logprob - self.history[(-1)]) if self.history else np.nan)
        message = self._template.format(iter=(self.iter + 1), logprob=logprob, delta=delta)
        print(message, file=sys.stderr)
    self.history.append(logprob)
    self.iter += 1
