Source code for torch_uncertainty.post_processing.calibration.temperature_scaler
from typing import Literal
import torch
from torch import Tensor, nn
from .scaler import Scaler
[docs]class TemperatureScaler(Scaler):
def __init__(
self,
model: nn.Module | None = None,
init_val: float = 1,
lr: float = 0.1,
max_iter: int = 100,
device: Literal["cpu", "cuda"] | torch.device | None = None,
) -> None:
"""Temperature scaling post-processing for calibrated probabilities.
Args:
model (nn.Module): Model to calibrate.
init_val (float, optional): Initial value for the temperature.
Defaults to 1.
lr (float, optional): Learning rate for the optimizer. Defaults to 0.1.
max_iter (int, optional): Maximum number of iterations for the
optimizer. Defaults to 100.
device (Optional[Literal["cpu", "cuda"]], optional): Device to use
for optimization. Defaults to None.
Reference:
Guo, C., Pleiss, G., Sun, Y., & Weinberger, K. Q. On calibration
of modern neural networks. In ICML 2017.
"""
super().__init__(model=model, lr=lr, max_iter=max_iter, device=device)
if init_val <= 0:
raise ValueError("Initial temperature value must be positive.")
self.set_temperature(init_val)
[docs] def set_temperature(self, val: float) -> None:
"""Set the temperature to a fixed value.
Args:
val (float): Temperature value.
"""
if val <= 0:
raise ValueError("Temperature value must be positive.")
self.temp = nn.Parameter(
torch.ones(1, device=self.device) * val, requires_grad=True
)
def _scale(self, logits: Tensor) -> Tensor:
"""Scale the prediction with the optimal temperature.
Args:
logits (Tensor): logits to be scaled.
Returns:
Tensor: Scaled logits.
"""
return logits / self.temperature[0]
@property
def temperature(self) -> list:
return [self.temp]