class MV_Impl(object):
def __init__(self):
self._mean = Avg(self.source, self.timeframe)
self._mean2 = Avg(Sqr(self.source), self.timeframe)
_internals = ["_mean", '_mean2']
def __repr__(self):
return self.label
def bind(self, ctx):
self._scheduler = ctx.world
def __call__(self):
return self.at(self._scheduler.currentTime)
def at(self, t):
M2 = self._mean2.at(t)
M = self._mean.at(t)
if M2 is not None and t > self._mean.startT:
var = M2 - M*M
if var < 0: # we have roundings errors
var = 0
return var
else:
return None
def __init__(self):
self._mean = Avg(self.source, self.timeframe)
self._mean2 = Avg(Sqr(self.source), self.timeframe)
