lightning/pytorch_lightning/trainer/supporters.py

59 lines
1.8 KiB
Python

import torch
class TensorRunningMean(object):
"""
Tracks a running mean without graph references.
Round robbin for the mean
Examples:
>>> accum = TensorRunningMean(5)
>>> accum.last(), accum.mean()
(None, None)
>>> accum.append(torch.tensor(1.5))
>>> accum.last(), accum.mean()
(tensor(1.5000), tensor(1.5000))
>>> accum.append(torch.tensor(2.5))
>>> accum.last(), accum.mean()
(tensor(2.5000), tensor(2.))
>>> accum.reset()
>>> _= [accum.append(torch.tensor(i)) for i in range(13)]
>>> accum.last(), accum.mean()
(tensor(12.), tensor(10.))
"""
def __init__(self, window_length: int):
self.window_length = window_length
self.memory = torch.Tensor(self.window_length)
self.current_idx: int = 0
self.last_idx: int = None
self.rotated: bool = False
def reset(self) -> None:
self = TensorRunningMean(self.window_length)
def last(self):
if self.last_idx is not None:
return self.memory[self.last_idx]
def append(self, x):
# map proper type for memory if they don't match
if self.memory.type() != x.type():
self.memory.type_as(x)
# store without grads
with torch.no_grad():
self.memory[self.current_idx] = x
self.last_idx = self.current_idx
# increase index
self.current_idx += 1
# reset index when hit limit of tensor
self.current_idx = self.current_idx % self.window_length
if self.current_idx == 0:
self.rotated = True
def mean(self):
if self.last_idx is not None:
return self.memory.mean() if self.rotated else self.memory[:self.current_idx].mean()