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import torch
import numpy as np
import torch.nn.functional as F
from torch import nn
def KL(P,Q,mask=None):
eps = 0.0000001
d = (P+eps).log()-(Q+eps).log()
d = P*d
if mask !=None:
d = d*mask
return torch.sum(d)
def CE(P,Q,mask=None):
return KL(P,Q,mask)+KL(1-P,1-Q,mask)
def algorithm2(P,Q,Y):
eps = 0.0000001
mean = P.mean(dim=1)
mask1 = P>=mean
mask2 = Y == Y.t()
mask = mask1 == mask2
loss =torch.mean(P * torch.log((P + eps) / (Q + eps)))
return loss
def umap(output_net, target_net, eps=0.0000001):
# Normalize each vector by its norm
(n, d) = output_net.shape
output_net_norm = torch.sqrt(torch.sum(output_net ** 2, dim=1, keepdim=True))
output_net = output_net / (output_net_norm + eps)
output_net[output_net != output_net] = 0
target_net_norm = torch.sqrt(torch.sum(target_net ** 2, dim=1, keepdim=True))
target_net = target_net / (target_net_norm + eps)
target_net[target_net != target_net] = 0
# Calculate the cosine similarity
model_similarity = torch.mm(output_net, output_net.transpose(0, 1))
model_distance = 1-model_similarity #[0,2]
model_distance[range(n), range(n)] = 3
model_distance = model_distance - torch.min(model_distance, dim=1)[0].view(-1, 1)
model_distance[range(n), range(n)] = 0
model_similarity = 1-model_distance
target_similarity = torch.mm(target_net, target_net.transpose(0, 1))
target_distance = 1-target_similarity
target_distance[range(n), range(n)] = 3
target_distance = target_distance - torch.min(target_distance,dim=1)[0].view(-1,1)
target_distance[range(n), range(n)] = 0
target_similarity = 1 - target_distance
# Scale cosine similarity to 0..1
model_similarity = (model_similarity + 1.0) / 2.0
target_similarity = (target_similarity + 1.0) / 2.0
# Transform them into probabilities
model_similarity = model_similarity / torch.sum(model_similarity, dim=1, keepdim=True)
target_similarity = target_similarity / torch.sum(target_similarity, dim=1, keepdim=True)
# Calculate the KL-divergence
loss = CE(target_similarity,model_similarity)
return loss
def supervised_umap(output_net, target_net,y,sample_weight=0, eps=0.0000001):
# Normalize each vector by its norm
(n, d) = output_net.shape
distance = 2.0
tahn = nn.Tanh()
sample_weight = sample_weight.view(-1,n)
sample_weight_matrix = (sample_weight+sample_weight.t())/32.0
sample_weight_matrix = tahn(sample_weight_matrix)
y = y.view(-1,n)
# print("y",y)
mask =1- (y==y.t()).float()
mask[mask == 0] = -1
distance = distance*mask*sample_weight_matrix
output_net_norm = torch.sqrt(torch.sum(output_net ** 2, dim=1, keepdim=True))
output_net = output_net / (output_net_norm + eps)
output_net[output_net != output_net] = 0
target_net_norm = torch.sqrt(torch.sum(target_net ** 2, dim=1, keepdim=True))
target_net = target_net / (target_net_norm + eps)
target_net[target_net != target_net] = 0
# Calculate the cosine similarity
model_similarity = torch.mm(output_net, output_net.transpose(0, 1))
model_distance = 1 - model_similarity # [0,2]
model_distance[range(n), range(n)] = 100000
model_distance = model_distance - torch.min(model_distance, dim=1)[0].view(-1, 1)
model_distance[range(n), range(n)] = 0
model_distance = torch.clamp(model_distance, 0+eps, 2.0-eps)
model_similarity = 1 - model_distance
target_similarity = torch.mm(target_net, target_net.transpose(0, 1))
target_distance = 1 - target_similarity
target_distance[range(n), range(n)] = 100000
p = torch.min(target_distance, dim=1)
target_distance = target_distance - p[0].view(-1, 1)
target_distance[range(n), range(n)] = 0
target_distance = (1 - sample_weight_matrix) * target_distance + distance
target_distance = torch.clamp(target_distance, 0+eps, 2.0-eps)
target_similarity = 1 - target_distance
# Scale cosine similarity to 0..1
model_similarity = (model_similarity + 1.0) / 2.0
target_similarity = (target_similarity + 1.0) / 2.0
# # Transform them into probabilities
model_similarity = model_similarity / torch.sum(model_similarity, dim=1, keepdim=True)
target_similarity = target_similarity / torch.sum(target_similarity, dim=1, keepdim=True)
# Calculate the CE-Loss
loss = CE(target_similarity, model_similarity)
return loss
def cosine_similarity_loss(output_net, target_net, eps=0.0000001):
# Normalize each vector by its norm
output_net_norm = torch.sqrt(torch.sum(output_net ** 2, dim=1, keepdim=True))
output_net = output_net / (output_net_norm + eps)
output_net[output_net != output_net] = 0
target_net_norm = torch.sqrt(torch.sum(target_net ** 2, dim=1, keepdim=True))
target_net = target_net / (target_net_norm + eps)
target_net[target_net != target_net] = 0
# Calculate the cosine similarity
model_similarity = torch.mm(output_net, output_net.transpose(0, 1))
target_similarity = torch.mm(target_net, target_net.transpose(0, 1))
# Scale cosine similarity to 0..1
model_similarity = (model_similarity + 1.0) / 2.0
target_similarity = (target_similarity + 1.0) / 2.0
# Transform them into probabilities
model_similarity = model_similarity / torch.sum(model_similarity, dim=1, keepdim=True)
target_similarity = target_similarity / torch.sum(target_similarity, dim=1, keepdim=True)
# Calculate the KL-divergence
loss = CE(target_similarity, model_similarity)
return loss
class dual_softmax_loss(nn.Module):
def __init__(self, ):
super(dual_softmax_loss, self).__init__()
def forward(self, sim_matrix, temp=1000):
sim_matrix = sim_matrix * F.softmax(sim_matrix / temp, dim=0) * len(
sim_matrix) # With an appropriate temperature parameter, the model achieves higher performance
logpt = F.log_softmax(sim_matrix, dim=-1) # row softmax and column softmax
logpt = torch.diag(logpt)
loss = -logpt
return loss
def log_sum_exp(x):
'''Utility function for computing log-sun-exp while determining
This will be used to determine unaveraged confidence loss across all examples in a batch.
'''
x_max = x.data.max()
return torch.log(torch.sum(torch.exp(x - x_max), -1, keepdim=True)) + x_max
def l2norm(X, dim, eps=1e-8):
"""L2-normalize columns of X
"""
norm = torch.pow(X, 2).sum(dim=dim, keepdim=True).sqrt() + eps
X = torch.div(X, norm)
return X
def calcdist(img, txt):
'''
Input img = (batch,dim), txt = (batch,dim)
Output Euclid Distance Matrix = Tensor(batch,batch), and dist[i,j] = d(img_i,txt_j)
'''
dist = img.unsqueeze(1) - txt.unsqueeze(0)
dist = torch.sum(torch.pow(dist, 2), dim=2)
return torch.sqrt(dist)
def calcmatch(label):
'''
Input label = (batch,)
Output Match Matrix =Tensor(batch,batch) and match[i,j] == 1 iff. label[i]==label[j]
'''
match = label.unsqueeze(1) - label.unsqueeze(0)
match[match != 0] = 1
return 1 - match
def calcneg(dist, label, anchor, positive):
'''
Input dist = (batch,batch), label = (batch,), anchor = index, positive = index
Output chosen negative sample index
'''
standard = dist[anchor, positive] # positive distance
dist = dist[anchor] - standard # distance of other samples
if max(dist[label != label[anchor]]) >= 0: # there exists valid negative
dist[dist < 0] = max(dist) + 2 # delete negative samples below standard
dist[label == label[anchor]] = max(dist) + 2 # delete positive samples
return int(torch.argmin(dist).cpu()) # return the closest negative sample
else: # choose argmax
dist[label == label[anchor]] = min(dist) - 2 # delete positive samples
return int(torch.argmax(dist).cpu())
def calcneg_dot(img, txt, match, anchor, positive):
'''
Input img = (batch,dim), txt = (batch,dim), match = (batch,batch), anchor = index, positive = index
Output chosen negative sample index
'''
distdot = torch.sum(torch.mul(img.unsqueeze(1), txt.unsqueeze(0)), 2)
distdot[match == 1] = -66666
return int(torch.argmax(distdot[anchor]).cpu())
def Triplet(img, txt, label):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,)
Output dist = (batch,batch),match = (batch,batch), triplets = List with shape(pairs,3)
'''
triplet_list = []
batch = img.shape[0]
dist = calcdist(img, txt)
match = calcmatch(label)
match_n = match.cpu().numpy()
positive_list = np.argwhere(match_n == 1).tolist() # the index list of all positive samples
for positive in positive_list:
negative = calcneg(dist, label, positive[0], positive[1]) # calculate negatives
# negative = calcneg_dot(img, txt, match, anchor, positive) # calculate negative with dot 效果很差
triplet_list.append([positive[0], int(positive[1].cuda()), negative])
return dist, match, triplet_list
def Positive(img, txt, label):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,)
Output dist = (batch,batch),match = (batch,batch), positives = List with shape(pairs,2)
Remark: return (anchor,positive) without finding triplets
'''
batch = img.shape[0]
dist = calcdist(img, txt)
match = calcmatch(label)
sample_list = torch.tensor([x for x in range(batch)]).int().cuda()
positive_list = [[i, int(j.cpu())] for i in range(batch) for j in sample_list[label == label[i]]]
return dist, match, positive_list
def Modality_invariant_Loss(img, txt, label, margin=0.2):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,), margin = parameter
Calculate invariant loss between images and texts belonging to the same class
'''
batch = img.shape[0]
dist = calcdist(img, txt)
dist = torch.pow(dist, 2)
match = calcmatch(label) # similar is 1, dissimilar is 0
pos = torch.mul(dist, match)
loss = torch.sum(pos)
return loss / batch
def Contrastive_Loss(img, txt, label, margin=0.2):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,), margin = parameter
Calculate triplet loss
'''
batch = img.shape[0]
dist = calcdist(img, txt)
dist = torch.pow(dist, 2)
match = calcmatch(label) # similar is 1, dissimilar is 0
pos = torch.mul(dist, match)
neg = margin - torch.mul(dist, 1 - match)
neg = torch.clamp(neg, 0)
loss = torch.sum(pos) + torch.sum(neg)
return loss / batch
def Triplet_Loss(img, txt, label, margin=0.2, semi_hard=True):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,), margin = parameter
Calculate triplet loss
'''
loss = 0
dist = calcdist(img, txt)
dist = torch.pow(dist, 2)
match = calcmatch(label)
match_n = match.cpu().numpy()
positive = np.argwhere(match_n == 1).tolist() # the index list of all positive samples
for x in positive:
# # Semi-Hard Negative Mining
if semi_hard:
neg_index = torch.where(
match[x[0]] == 0) # the index list of all negative samples (shared by image and text)
neg_dis = dist[x[0]][neg_index]
tmp = dist[x[0], x[1]] - neg_dis + margin
tmp = torch.clamp(tmp, 0)
loss = loss + torch.sum(tmp, dim=-1)
else:
# Hard Negative Mining
negative = calcneg(dist, label, x[0], x[1]) # calculate hard negative
tmp = dist[x[0], x[1]] - dist[x[0], negative] + margin
if tmp > 0:
loss = loss + tmp
return loss / len(positive)
def Lifted_Loss(img, txt, label, margin=1): # the margin is set to be 1 as the original paper
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,), margin = parameter
Calculate lifted structured embedding loss
'''
# dist, match, positive = Positive(img, txt, label)
dist = calcdist(img, txt)
match = calcmatch(label)
match_n = match.cpu().numpy()
positive = np.argwhere(match_n == 1).tolist() # the index list of all positive samples
loss = 0
for x in positive:
neg_index = torch.where(match[x[0]] == 0) # the index list of all negative samples (shared by image and text)
neg_dis_anchor = dist[x[0]][neg_index]
neg_dis_postive = dist[x[1]][neg_index]
tmp = dist[x[0], x[1]] + log_sum_exp(margin - neg_dis_postive) + log_sum_exp(margin - neg_dis_anchor)
loss = loss + tmp
return loss / (2 * len(positive))
def Npairs(img, txt, label, margin=0.2, alpha=0.1):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,), margin = parameter, alpha = parameter
Calculate N-pairs loss
'''
# dist, match, positive = Positive(img, txt, label)
batch = img.shape[0]
distdot_it = torch.exp(F.linear(img, txt))
# distdot_ti = torch.t(distdot)
# !!!!!!!!!!!!!
distdot_ti = torch.t(distdot_it)
# !!!!!!!!!!!!!
match = calcmatch(label)
match_n = match.cpu().numpy()
positive = np.argwhere(match_n == 1).tolist() # the index list of all positive samples
loss = 0
for x in positive:
neg_index = torch.where(match[x[0]] == 0) # the index list of all negative samples
tmp_i2t = distdot_it[x[0], x[1]] - log_sum_exp(distdot_it[x[0]][neg_index])
tmp_t2i = distdot_ti[x[0], x[1]] - log_sum_exp(distdot_ti[x[0]][neg_index])
loss = loss + (tmp_i2t + tmp_t2i) / 2
loss = -loss / len(positive)
for x in range(batch):
loss = loss + alpha * (torch.norm(img[x]) + torch.norm(txt[x])) / batch
return loss
def Supervised_Contrastive_Loss(img, txt, label):
'''
Input img = (batch,dim), txt = (batch,dim), label = (batch,), margin = parameter
An unofficial implementation of supervised contrastive loss for multimodal learning
'''
loss = 0
batch = img.shape[0]
dist = calcdist(img, txt)
dist = torch.pow(dist, 2)
dist = dist / (torch.sum(dist) / (batch * batch)) # scale the metric
match = calcmatch(label) # 相似为1,不相似为0
match_n = match.cpu().numpy()
positive = np.argwhere(match_n == 1).tolist() # the index list of all positive samples
loss = 0
for x in positive:
neg_index = torch.where(match[x[0]] == 0) # the index list of all negative samples
pos_sim = -dist[x[0], x[1]]
neg_sims = -dist[x[0]][neg_index]
tmp = pos_sim - log_sum_exp(neg_sims)
loss = loss + tmp
loss = -loss / len(positive)
return loss
def regularization(features, centers, labels):
# features = l2norm(features, dim=-1)
distance = (features - centers[labels])
distance = torch.sum(torch.pow(distance, 2), 1, keepdim=True)
distance = (torch.sum(distance, 0, keepdim=True)) / features.shape[0]
return distance
def PAN(features, centers, labels, add_regularization=False):
"""The prototype contrastive loss and regularization loss in
PAN(https://dl.acm.org/doi/abs/10.1145/3404835.3462867)"""
batch = features.shape[0]
features_square = torch.sum(torch.pow(features, 2), 1, keepdim=True) # 在第一个维度上平方
centers_square = torch.sum(torch.pow(torch.t(centers), 2), 0, keepdim=True)
features_into_centers = 2 * torch.matmul(features, torch.t(centers))
dist = -(features_square + centers_square - features_into_centers)
output = F.log_softmax(dist, dim=1)
dce_loss = F.nll_loss(output, labels)
if add_regularization:
reg_loss = regularization(features, centers, labels)
loss = dce_loss + reg_loss
loss = dce_loss
return loss / batch
def Label_Regression_Loss(view1_predict, view2_predict, label_onehot):
loss = ((view1_predict - label_onehot.float()) ** 2).sum(1).sqrt().mean() + (
(view2_predict - label_onehot.float()) ** 2).sum(1).sqrt().mean()
return loss
def Proxy_NCA(features, label, proxies, mrg=0.1, alpha=1):
"""
Input:
:param feature: [2*batch, dim] concat image and text features
:param label: [2*batch]
:param proxies: [feature_dim, n_classes]
:return: Proxy Anchor loss
"""
P = torch.t(proxies) # [feature_dim, n_classes]-->[n_classes, feature_dim]
n_classes = P.shape[0]
# similar to Proxc-NCA and Normlized Softmax
cos = F.linear(features, P) # Calcluate cosine similarity [batch, n_classes]
# Proxy-NCA loss (similar to Normlized Softmax and PAN,while the denominator does not contain positive prototype)
loss = 0
for x in range(features.shape[0]):
pos = torch.exp(cos[x, label[x]])
neg = torch.exp(cos[x]).sum(dim=-1) - pos
loss = loss + torch.log(pos / neg)
loss = -loss / features.shape[0]
return loss
def Proxy_Anchor(features, label, proxies, mrg=0.1, alpha=1):
"""
Input:
:param
feature: [2 * batch, dim]
concat
image and text
features
:param
label: [2 * batch]
:param
proxies: [feature_dim, n_classes]
:return: Proxy
Anchor
loss
"""
P = torch.t(proxies) # [feature_dim, n_classes]-->[n_classes, feature_dim]
n_classes = P.shape[0]
# similar to Proxc-NCA and Normlized Softmax
cos = F.linear(features, P) # Calcluate cosine similarity [batch, n_classes]
P_one_hot = label # [batch, n_classes]
N_one_hot = 1 - P_one_hot
pos_exp = torch.exp(-alpha * (cos - mrg)) # [batch, n_class]
neg_exp = torch.exp(alpha * (cos + mrg)) # 出现了e+30导致nan
with_pos_proxies = torch.nonzero(P_one_hot.sum(dim=0) != 0).squeeze(
dim=1) # The set of positive proxies of data in the batch
num_valid_proxies = len(with_pos_proxies) # The number of positive proxies
P_sim_sum = torch.where(P_one_hot == 1, pos_exp, torch.zeros_like(pos_exp)).sum(dim=0)
N_sim_sum = torch.where(N_one_hot == 1, neg_exp, torch.zeros_like(neg_exp)).sum(dim=0)
pos_term = torch.log(1 + P_sim_sum).sum() / num_valid_proxies
neg_term = torch.log(1 + N_sim_sum).sum() / n_classes
loss = pos_term + neg_term
return loss
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