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import numpy as np | ||
import torch | ||
import torch.nn as nn | ||
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# https://github.com/passalis/pkth/blob/master/nn/pkt_transfer.py | ||
def prob_loss(teacher_features, student_features, eps=1e-6, kernel_parameters={}): | ||
# Teacher kernel | ||
if kernel_parameters['teacher'] == 'rbf': | ||
teacher_d = pairwise_distances(teacher_features) | ||
if 'teacher_sigma' in kernel_parameters: | ||
sigma = kernel_parameters['teacher_sigma'] | ||
else: | ||
sigma = 1 | ||
teacher_s = torch.exp(-teacher_d / sigma) | ||
elif kernel_parameters['teacher'] == 'adaptive_rbf': | ||
teacher_d = pairwise_distances(teacher_features) | ||
sigma = torch.mean(teacher_d).detach() | ||
teacher_s = torch.exp(-teacher_d / sigma) | ||
elif kernel_parameters['teacher'] == 'cosine': | ||
teacher_s = cosine_pairwise_similarities(teacher_features) | ||
elif kernel_parameters['teacher'] == 'student_t': | ||
teacher_d = pairwise_distances(teacher_features) | ||
if 'teacher_d' in kernel_parameters: | ||
d = kernel_parameters['teacher_d'] | ||
else: | ||
d = 1 | ||
teacher_s = 1.0 / (1 + teacher_d ** d) | ||
elif kernel_parameters['teacher'] == 'cauchy': | ||
teacher_d = pairwise_distances(teacher_features) | ||
if 'teacher_sigma' in kernel_parameters: | ||
sigma = kernel_parameters['teacher_sigma'] | ||
else: | ||
sigma = 1 | ||
teacher_s = 1.0 / (1 + (teacher_d ** 2 / sigma ** 2)) | ||
elif kernel_parameters['teacher'] == 'combined': | ||
teacher_d = pairwise_distances(teacher_features) | ||
if 'teacher_d' in kernel_parameters: | ||
d = kernel_parameters['teacher_d'] | ||
else: | ||
d = 1 | ||
teacher_s_2 = 1.0 / (1 + teacher_d ** d) | ||
teacher_s_1 = cosine_pairwise_similarities(teacher_features) | ||
else: | ||
assert False | ||
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# Student kernel | ||
if kernel_parameters['student'] == 'rbf': | ||
student_d = pairwise_distances(student_features) | ||
if 'student_sigma' in kernel_parameters: | ||
sigma = kernel_parameters['student_sigma'] | ||
else: | ||
sigma = 1 | ||
student_s = torch.exp(-student_d / sigma) | ||
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elif kernel_parameters['student'] == 'adaptive_rbf': | ||
student_d = pairwise_distances(student_features) | ||
sigma = torch.mean(student_d).detach() | ||
student_s = torch.exp(-student_d / sigma) | ||
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elif kernel_parameters['student'] == 'cosine': | ||
student_s = cosine_pairwise_similarities(student_features) | ||
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elif kernel_parameters['student'] == 'student_t': | ||
student_d = pairwise_distances(student_features) | ||
if 'student_d' in kernel_parameters: | ||
d = kernel_parameters['student_d'] | ||
else: | ||
d = 1 | ||
student_s = 1.0 / (1 + student_d ** d) | ||
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elif kernel_parameters['student'] == 'cauchy': | ||
student_d = pairwise_distances(student_features) | ||
if 'student_sigma' in kernel_parameters: | ||
sigma = kernel_parameters['student_sigma'] | ||
else: | ||
sigma = 1 | ||
student_s = 1.0 / (1 + (student_d ** 2 / sigma ** 2)) | ||
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elif kernel_parameters['student'] == 'combined': | ||
student_d = pairwise_distances(student_features) | ||
if 'student_d' in kernel_parameters: | ||
d = kernel_parameters['student_d'] | ||
else: | ||
d = 1 | ||
student_s_2 = 1.0 / (1 + student_d ** d) | ||
student_s_1 = cosine_pairwise_similarities(student_features) | ||
else: | ||
assert False | ||
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if kernel_parameters['teacher'] == 'combined': | ||
# Transform them into probabilities | ||
teacher_s_1 = teacher_s_1 / torch.sum(teacher_s_1, dim=1, keepdim=True) | ||
student_s_1 = student_s_1 / torch.sum(student_s_1, dim=1, keepdim=True) | ||
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teacher_s_2 = teacher_s_2 / torch.sum(teacher_s_2, dim=1, keepdim=True) | ||
student_s_2 = student_s_2 / torch.sum(student_s_2, dim=1, keepdim=True) | ||
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else: | ||
# Transform them into probabilities | ||
teacher_s = teacher_s / torch.sum(teacher_s, dim=1, keepdim=True) | ||
student_s = student_s / torch.sum(student_s, dim=1, keepdim=True) | ||
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if 'loss' in kernel_parameters: | ||
if kernel_parameters['loss'] == 'kl': | ||
loss = teacher_s * torch.log(eps + (teacher_s) / (eps + student_s)) | ||
elif kernel_parameters['loss'] == 'abs': | ||
loss = torch.abs(teacher_s - student_s) | ||
elif kernel_parameters['loss'] == 'squared': | ||
loss = (teacher_s - student_s) ** 2 | ||
elif kernel_parameters['loss'] == 'jeffreys': | ||
loss = (teacher_s - student_s) * (torch.log(teacher_s) - torch.log(student_s)) | ||
elif kernel_parameters['loss'] == 'exponential': | ||
loss = teacher_s * (torch.log(teacher_s) - torch.log(student_s)) ** 2 | ||
elif kernel_parameters['loss'] == 'kagan': | ||
loss = ((teacher_s - student_s) ** 2) / teacher_s | ||
elif kernel_parameters['loss'] == 'combined': | ||
# Jeffrey's combined | ||
loss1 = (teacher_s_1 - student_s_1) * (torch.log(teacher_s_1) - torch.log(student_s_1)) | ||
loss2 = (teacher_s_2 - student_s_2) * (torch.log(teacher_s_2) - torch.log(student_s_2)) | ||
else: | ||
assert False | ||
else: | ||
loss = teacher_s * torch.log(eps + (teacher_s) / (eps + student_s)) | ||
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if 'loss' in kernel_parameters and kernel_parameters['loss'] == 'combined': | ||
loss = torch.mean(loss1) + torch.mean(loss2) | ||
else: | ||
loss = torch.mean(loss) | ||
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return loss | ||
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def pairwise_distances(a, b=None, eps=1e-6): | ||
""" | ||
Calculates the pairwise distances between matrices a and b (or a and a, if b is not set) | ||
:param a: | ||
:param b: | ||
:return: | ||
""" | ||
if b is None: | ||
b = a | ||
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aa = torch.sum(a ** 2, dim=1) | ||
bb = torch.sum(b ** 2, dim=1) | ||
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aa = aa.expand(bb.size(0), aa.size(0)).t() | ||
bb = bb.expand(aa.size(0), bb.size(0)) | ||
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AB = torch.mm(a, b.transpose(0, 1)) | ||
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dists = aa + bb - 2 * AB | ||
dists = torch.clamp(dists, min=0, max=np.inf) | ||
dists = torch.sqrt(dists + eps) | ||
return dists | ||
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def cosine_pairwise_similarities(features, eps=1e-6, normalized=True): | ||
features_norm = torch.sqrt(torch.sum(features ** 2, dim=1, keepdim=True)) | ||
features = features / (features_norm + eps) | ||
features[features != features] = 0 | ||
similarities = torch.mm(features, features.transpose(0, 1)) | ||
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if normalized: | ||
similarities = (similarities + 1.0) / 2.0 | ||
return similarities | ||
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class HKDLoss(nn.Module): | ||
"""Heterogeneous Knowledge Distillation using Information Flow Modeling, CVPR2020""" | ||
def __init__(self, init_weight=100, decay=0.7): | ||
super(HKDLoss, self).__init__() | ||
self.init_weight = init_weight | ||
self.decay = decay | ||
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def forward(self, f_s, f_t): | ||
kernel_parameters = {'teacher': 'combined', 'student': 'combined', 'loss': 'combined'} | ||
for i, (teacher, student) in enumerate(zip(f_t, f_s)): | ||
teacher = teacher.view(teacher.shape[0], -1) | ||
student = student.view(student.shape[0], -1) | ||
if i == 0: | ||
weight = self.init_weight | ||
loss = weight * prob_loss(teacher, student, kernel_parameters=kernel_parameters) | ||
else: | ||
weight *= self.decay | ||
loss += prob_loss(teacher, student, kernel_parameters=kernel_parameters) | ||
return loss |
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@@ -8,3 +8,4 @@ | |
from .VID import VIDLoss | ||
from .IRG import IRGLoss | ||
from .SemCKD import SemCKDLoss | ||
from .HKD import HKDLoss |
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