meters.py

# encoding: utf-8
import math

import numpy as np


class AverageMeter(object):
    def __init__(self):
        self.n = 0
        self.sum = 0.0
        self.var = 0.0
        self.val = 0.0
        self.mean = np.nan
        self.std = np.nan

    def update(self, value, n=1):
        self.val = value
        self.sum += value
        self.var += value * value
        self.n += n

        if self.n == 0:
            self.mean, self.std = np.nan, np.nan
        elif self.n == 1:
            self.mean, self.std = self.sum, np.inf
        else:
            self.mean = self.sum / self.n
            self.std = math.sqrt(
                (self.var - self.n * self.mean * self.mean) / (self.n - 1.0))

    def value(self):
        return self.mean, self.std

    def reset(self):
        self.n = 0
        self.sum = 0.0
        self.var = 0.0
        self.val = 0.0
        self.mean = np.nan
        self.std = np.nan