# -*- coding: utf-8 -*-
# (C) Copyright 2020, 2021, 2022, 2023, 2024 IBM. All Rights Reserved.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.
"""Base drift compensation for inference."""
from typing import Tuple
from torch import Tensor
from torch.autograd import no_grad
[docs]class BaseDriftCompensation:
"""Base class for drift compensations."""
def __init__(self) -> None:
pass
[docs] @no_grad()
def init_baseline(self, forward_output: Tensor) -> Tuple[Tensor, Tensor]:
"""Initialize the base line for applying the compensation.
Uses a all one tensor for read_out.
Args:
forward_output: forward output of the read out vector to compensate
Returns:
reference tensor readout
"""
ref_value = self.readout(forward_output)
return ref_value
[docs] @no_grad()
def get_readout_tensor(self, in_size: int) -> Tensor:
"""Return the read-out tensor.
Called once during :meth:`~init_baseline`.
"""
raise NotImplementedError
[docs] @no_grad()
def readout(self, out_tensor: Tensor) -> Tensor:
"""Implement the read out math."""
raise NotImplementedError
[docs] @no_grad()
def apply(self, forward_output: Tensor, ref_value: Tensor) -> Tensor:
"""Read out the current value from the output of the forward
pass and returns the drift compensation alpha scale."""
current_value = self.readout(forward_output)
ratio = ref_value / current_value
return ratio