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# Copyright (c) Aishwarya Kamath & Nicolas Carion. Licensed under the Apache License 2.0. All Rights Reserved
# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
"""
Modules to compute the matching cost and solve the corresponding LSAP.
"""
import torch
from scipy.optimize import linear_sum_assignment
from torch import nn
import pdb
from maskrcnn_benchmark.layers.set_loss import generalized_box_iou, box_iou
class HungarianMatcherCustom(nn.Module):
"""This class computes an assignment between the targets and the predictions of the network
For efficiency reasons, the targets don't include the no_object. Because of this, in general,
there are more predictions than targets. In this case, we do a 1-to-1 matching of the best predictions,
while the others are un-matched (and thus treated as non-objects).
"""
def __init__(self, cost_class: float = 1, cost_bbox: float = 1, cost_giou: float = 1, special = False):
"""Creates the matcher
Params:
cost_class: This is the relative weight of the classification error in the matching cost
cost_bbox: This is the relative weight of the L1 error of the bounding box coordinates in the matching cost
cost_giou: This is the relative weight of the giou loss of the bounding box in the matching cost
"""
super().__init__()
self.cost_class = cost_class
self.cost_bbox = cost_bbox
self.cost_giou = cost_giou
self.norm = nn.Softmax(-1)
self.special = special
assert cost_class != 0 or cost_bbox != 0 or cost_giou != 0, "all costs cant be 0"
@torch.no_grad()
def forward(self, outputs, targets):
"""Performs the matching
Params:
outputs: This is a dict that contains at least these entries:
"pred_logits": Tensor of dim [batch_size, num_queries, num_classes] with the classification logits
"pred_boxes": Tensor of dim [batch_size, num_queries, 4] with the predicted box coordinates
targets: This is a list of targets (len(targets) = batch_size), where each target is a dict containing:
"labels": Tensor of dim [num_target_boxes] (where num_target_boxes is the number of ground-truth
objects in the target) containing the class labels
"boxes": Tensor of dim [num_target_boxes, 4] containing the target box coordinates
Returns:
A list of size batch_size, containing tuples of (index_i, index_j) where:
- index_i is the indices of the selected predictions (in order)
- index_j is the indices of the corresponding selected targets (in order)
For each batch element, it holds:
len(index_i) = len(index_j) = min(num_queries, num_target_boxes)
"""
bs, num_queries = outputs["pred_logits"].shape[:2]
# We flatten to compute the cost matrices in a batch
out_prob = outputs["pred_logits"].flatten(0, 1) # [batch_size * num_queries, num_classes]
# out_prob_bg = 1 - out_prob
# out_prob = torch.cat([out_prob_bg, out_prob], dim = 1)
out_bbox = outputs["pred_boxes"].flatten(0, 1) # [batch_size * num_queries, 4]
# Also concat the target labels and boxes
tgt_bbox = targets["pred_boxes"].flatten(0, 1) # [batch_size * num_target_boxes, 4]
tgt_prob = targets["pred_logits"].flatten(0, 1) # [batch_size * num_target_boxes, num_classes]
# tgt_prob_bg = 1 - tgt_prob
# tgt_prob = torch.cat([tgt_prob_bg, tgt_prob], dim = 1)
# Compute the soft-cross entropy between the predicted token alignment and the GT one for each box
# import pdb
cost_class = out_prob - tgt_prob.transpose(0,1)
cost_class = cost_class.abs()
# Compute the L1 cost between boxes
cost_bbox = torch.cdist(out_bbox, tgt_bbox, p=1)
# Compute the giou cost betwen boxes
# cost_giou = -generalized_box_iou(box_cxcywh_to_xyxy(out_bbox), box_cxcywh_to_xyxy(tgt_bbox))
cost_giou, _ = box_iou(out_bbox, tgt_bbox)
cost_giou = -cost_giou
# Final cost matrix
C = self.cost_bbox * cost_bbox + self.cost_class * cost_class + self.cost_giou * cost_giou
C = C.view(bs, num_queries, -1).cpu()
C_class = cost_class
C_class = C_class.view(bs, num_queries, -1).cpu()
C_bbox = cost_bbox
C_bbox = C_bbox.view(bs, num_queries, -1).cpu()
#C[torch.isnan(C)] = 0.0
#C[torch.isinf(C)] = 0.0
#print(C)
sizes = [tgt_bbox.size(0)] # assum b = 1
indices = [linear_sum_assignment(c[i]) for i, c in enumerate(C.split(sizes, -1))]
assignment = [(torch.as_tensor(i, dtype=torch.int64), torch.as_tensor(j, dtype=torch.int64)) for i, j in indices]
# calculate the total cost;
assignment = assignment[0]
C = C[0]
C_class = C_class[0]
C_bbox = C_bbox[0]
cost = 0
selected_entries = []
cost_class = 0
cost_bbox = 0
cost_matched_box = 0
if self.special: # calculate the difference between boxes
for first_index, second_index in zip(assignment[0], assignment[1]):
if -C[first_index, second_index] > 0.5:
cost += C_class[first_index, second_index]
selected_entries.append(C[first_index, second_index])
cost_class += C_class[first_index, second_index]
cost_bbox += C_bbox[first_index, second_index]
else:
for first_index, second_index in zip(assignment[0], assignment[1]):
cost += C[first_index, second_index]
selected_entries.append(C[first_index, second_index])
cost_class += C_class[first_index, second_index]
cost_bbox += C_bbox[first_index, second_index]
print(selected_entries, cost)
return cost, len(selected_entries), selected_entries, cost_class, cost_bbox