Source code for ray.rllib.utils.schedules.piecewise_schedule

from ray.rllib.utils.schedules.schedule import Schedule


def _linear_interpolation(l, r, alpha):
    return l + alpha * (r - l)


[docs]class PiecewiseSchedule(Schedule): def __init__(self, endpoints, interpolation=_linear_interpolation, outside_value=None, framework=None): """ Args: endpoints (List[Tuple[int,float]]): A list of tuples `(t, value)` such that the output is an interpolation (given by the `interpolation` callable) between two values. E.g. t=400 and endpoints=[(0, 20.0),(500, 30.0)] output=20.0 + 0.8 * (30.0 - 20.0) = 28.0 NOTE: All the values for time must be sorted in an increasing order. interpolation (callable): A function that takes the left-value, the right-value and an alpha interpolation parameter (0.0=only left value, 1.0=only right value), which is the fraction of distance from left endpoint to right endpoint. outside_value (Optional[float]): If t in call to `value` is outside of all the intervals in `endpoints` this value is returned. If None then an AssertionError is raised when outside value is requested. """ super().__init__(framework=framework) idxes = [e[0] for e in endpoints] assert idxes == sorted(idxes) self.interpolation = interpolation self.outside_value = outside_value self.endpoints = endpoints def _value(self, t): for (l_t, l), (r_t, r) in zip(self.endpoints[:-1], self.endpoints[1:]): if l_t <= t < r_t: alpha = float(t - l_t) / (r_t - l_t) return self.interpolation(l, r, alpha) # t does not belong to any of the pieces, so doom. assert self.outside_value is not None return self.outside_value