def METHOD_NAME(self):
    """ See :meth:`Optimiser.stop()`. """
    if not self._running:
        return False
    # CMAES Stopping conditions:
    # tolconditioncov(1e14) ERROR CHECK: Condition of covariance matrix
    # tolfacupx(1e3) ERROR CHECK: Massive increases in step-size
    # timeout(inf) Limits real time
    # tolupsigma(1e20) Creeping / slow improvement
    # tolstagnation(has default) Threshold in unchanged iterations
    # tolx(1e-11) Threshold on change in position
    # ftarget(no default) Threshold on target function value
    # tolfun(1e-11) Threshold on change in target value (one iteration)
    # tolfunhist(1e-12) Threshold on long-term change in target value
    # maxfevals(inf) Max function evaluations
    # maxiter(has default) Max iterations
    # noeffectcoord ?
    # noeffectaxis ?
    # flat fitness: CMAES thinks the landscape is flat
    # "||xmean||^2<ftarget"
    # callback: User callback triggered stop
    METHOD_NAME = self._es.METHOD_NAME()
    if METHOD_NAME:
        if 'tolconditioncov' in METHOD_NAME:    # pragma: no cover
            return 'Ill-conditioned covariance matrix.'
        # self._logger.debug(
        #    'CMA-ES stopping condition(s) reached: ' +
        #    '; '.join([str(x) for x in stop.keys()]))
    return False