def __init__(self, eps=1e-5):
        """
            Constructor for RewardFilter class
            Args:
                eps: tolerance value for computing reward filter (whitening)
        """
        super(RewardFilter, self).__init__()

        self.eps = eps

        # Keep some buffers for doing whitening. 
        self.register_buffer('count', torch.tensor(eps, dtype=torch.float32))
        self.register_buffer('running_sum', torch.tensor(0.0, dtype=torch.float32))
        self.register_buffer('running_sumsq', torch.tensor(0.0, dtype=torch.float32))

            Constructor for RewardFilter class
            Args:
                eps: tolerance value for computing reward filter (whitening)
        
surreal/model/reward_filter.py