prototorch/prototorch/core/competitions.py
2021-06-15 15:41:28 +02:00

94 lines
2.2 KiB
Python

"""ProtoTorch competitions"""
import torch
def wtac(distances: torch.Tensor,
labels: torch.LongTensor) -> (torch.LongTensor):
"""Winner-Takes-All-Competition.
Returns the labels corresponding to the winners.
"""
winning_indices = torch.min(distances, dim=1).indices
winning_labels = labels[winning_indices].squeeze()
return winning_labels
def knnc(distances: torch.Tensor,
labels: torch.LongTensor,
k: int = 1) -> (torch.LongTensor):
"""K-Nearest-Neighbors-Competition.
Returns the labels corresponding to the winners.
"""
winning_indices = torch.topk(-distances, k=k, dim=1).indices
winning_labels = torch.mode(labels[winning_indices], dim=1).values
return winning_labels
def cbcc(detections: torch.Tensor, reasonings: torch.Tensor):
"""Classification-By-Components Competition.
Returns probability distributions over the classes.
`detections` must be of shape [batch_size, num_components].
`reasonings` must be of shape [num_components, num_classes, 2].
"""
A, B = reasonings.permute(2, 1, 0).clamp(0, 1)
pk = A
nk = (1 - A) * B
numerator = (detections @ (pk - nk).T) + nk.sum(1)
probs = numerator / (pk + nk).sum(1)
# probs = probs.squeeze(0)
return probs
class WTAC(torch.nn.Module):
"""Winner-Takes-All-Competition Layer.
Thin wrapper over the `wtac` function.
"""
def forward(self, distances, labels):
return wtac(distances, labels)
class LTAC(torch.nn.Module):
"""Loser-Takes-All-Competition Layer.
Thin wrapper over the `wtac` function.
"""
def forward(self, probs, labels):
return wtac(-1.0 * probs, labels)
class KNNC(torch.nn.Module):
"""K-Nearest-Neighbors-Competition.
Thin wrapper over the `knnc` function.
"""
def __init__(self, k=1, **kwargs):
super().__init__(**kwargs)
self.k = k
def forward(self, distances, labels):
return knnc(distances, labels, k=self.k)
def extra_repr(self):
return f"k: {self.k}"
class CBCC(torch.nn.Module):
"""Classification-By-Components Competition.
Thin wrapper over the `cbcc` function.
"""
def forward(self, detections, reasonings):
return cbcc(detections, reasonings)