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fix gram-matrix detector #228

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fix gram-matrix detector #228

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218 changes: 114 additions & 104 deletions openood/postprocessors/gram_postprocessor.py
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,8 @@

from .base_postprocessor import BasePostprocessor
from .info import num_classes_dict

from collections import defaultdict, Counter
import random

class GRAMPostprocessor(BasePostprocessor):
def __init__(self, config):
Expand All @@ -24,17 +25,21 @@ def __init__(self, config):
self.setup_flag = False

def setup(self, net: nn.Module, id_loader_dict, ood_loader_dict):
net = FeatureExtractor(net)
if not self.setup_flag:
self.feature_min, self.feature_max = sample_estimator(
self.feature_min, self.feature_max, self.normalize_factors = sample_estimator(
net, id_loader_dict['train'], self.num_classes, self.powers)
self.setup_flag = True
else:
pass
net.destroy_hooks()

def postprocess(self, net: nn.Module, data: Any):
net = FeatureExtractor(net)
preds, deviations = get_deviations(net, data, self.feature_min,
self.feature_max, self.num_classes,
self.feature_max, self.normalize_factors,
self.powers)
net.destroy_hooks()
return preds, deviations

def set_hyperparam(self, hyperparam: list):
Expand All @@ -47,121 +52,126 @@ def get_hyperparam(self):
def tensor2list(x):
return x.data.cuda().tolist()

def G_p(ob, p):
temp = ob.detach()

temp = temp**p
temp = temp.reshape(temp.shape[0],temp.shape[1],-1)
temp = ((torch.matmul(temp,temp.transpose(dim0=2,dim1=1)))).sum(dim=2)
temp = (temp.sign()*torch.abs(temp)**(1/p)).reshape(temp.shape[0],-1)

return temp

def delta(mins, maxs, x):
dev = (F.relu(mins-x)/torch.abs(mins+10**-6)).sum(dim=1,keepdim=True)
dev += (F.relu(x-maxs)/torch.abs(maxs+10**-6)).sum(dim=1,keepdim=True)
return dev

class FeatureExtractor(torch.nn.Module):
# Inspired from https://github.com/paaatcha/gram-ood
def __init__(self, torch_model):
super().__init__()
self.torch_model = torch_model
self.feat_list = list()
def _hook_fn(_, input, output):
self.feat_list.append(output)

# To set a different layer, you must use this function:
def hook_layers(torch_model):
hooked_layers = list()
for layer in torch_model.modules():
if isinstance(layer, nn.ReLU) or isinstance(layer, nn.Conv2d):
hooked_layers.append(layer)
return hooked_layers

def register_layers(layers):
regs_layers = list()
for lay in layers:
regs_layers.append(lay.register_forward_hook(_hook_fn))
return regs_layers

## Setting the hook
hl = hook_layers (torch_model)
self.rgl = register_layers (hl)
# print(f"{len(self.rgl)} Features")

def forward(self, x, return_feature_list=True):
preds = self.torch_model(x)
list = self.feat_list.copy()
self.feat_list.clear()
return preds, list

def destroy_hooks(self):
for lay in self.rgl:
lay.remove()

@torch.no_grad()
def sample_estimator(model, train_loader, num_classes, powers):

model.eval()

num_layer = 5 # 4 for lenet
num_poles_list = powers
num_poles = len(num_poles_list)
feature_class = [[[None for x in range(num_poles)]
for y in range(num_layer)] for z in range(num_classes)]
label_list = []
mins = [[[None for x in range(num_poles)] for y in range(num_layer)]
for z in range(num_classes)]
maxs = [[[None for x in range(num_poles)] for y in range(num_layer)]
for z in range(num_classes)]

gram_features = defaultdict(lambda: defaultdict(lambda: defaultdict(lambda : None)))
mins = dict()
maxs = dict()
class_counts = Counter()
# collect features and compute gram metrix
for batch in tqdm(train_loader, desc='Compute min/max'):
data = batch['data'].cuda()
label = batch['label']
_, feature_list = model(data, return_feature_list=True)
label_list = tensor2list(label)
for layer_idx in range(num_layer):

for pole_idx, p in enumerate(num_poles_list):
temp = feature_list[layer_idx].detach()

temp = temp**p
temp = temp.reshape(temp.shape[0], temp.shape[1], -1)
temp = ((torch.matmul(temp,
temp.transpose(dim0=2,
dim1=1)))).sum(dim=2)
temp = (temp.sign() * torch.abs(temp)**(1 / p)).reshape(
temp.shape[0], -1)

temp = tensor2list(temp)
for feature, label in zip(temp, label_list):
if isinstance(feature_class[label][layer_idx][pole_idx],
type(None)):
feature_class[label][layer_idx][pole_idx] = feature
class_counts.update(Counter(label.cpu().numpy()))
for layer_idx, feature in enumerate(feature_list):
for power in powers:
gram_feature = G_p(feature, power).cpu()
for class_ in range(num_classes):
if gram_features[layer_idx][power][class_] is None:
gram_features[layer_idx][power][class_] = gram_feature[label==class_]
else:
feature_class[label][layer_idx][pole_idx].extend(
feature)
gram_features[layer_idx][power][class_] = torch.cat([gram_features[layer_idx][power][class_],gram_feature[label==class_]],dim=0)

val_idxs = {}
train_idxs = {}
for c in class_counts:
L = class_counts[c]
val_idxs[c] = random.sample(range(L),int(0.1*L))
train_idxs[c] = list(set(range(L)) - set(val_idxs[c]))
normalize_factors = []
# compute mins/maxs
for label in range(num_classes):
for layer_idx in range(num_layer):
for poles_idx in range(num_poles):
feature = torch.tensor(
np.array(feature_class[label][layer_idx][poles_idx]))
current_min = feature.min(dim=0, keepdim=True)[0]
current_max = feature.max(dim=0, keepdim=True)[0]

if mins[label][layer_idx][poles_idx] is None:
mins[label][layer_idx][poles_idx] = current_min
maxs[label][layer_idx][poles_idx] = current_max
else:
mins[label][layer_idx][poles_idx] = torch.min(
current_min, mins[label][layer_idx][poles_idx])
maxs[label][layer_idx][poles_idx] = torch.max(
current_min, maxs[label][layer_idx][poles_idx])

return mins, maxs


def get_deviations(model, data, mins, maxs, num_classes, powers):
for layer_idx in gram_features:
total_delta = None
for class_ in class_counts:
trn = train_idxs[class_]
val = val_idxs[class_]
class_deltas = 0
for power in powers:
mins[layer_idx,power,class_] = gram_features[layer_idx][power][class_][trn].min(dim=0,keepdim=True)[0]
maxs[layer_idx,power,class_] = gram_features[layer_idx][power][class_][trn].max(dim=0,keepdim=True)[0]
class_deltas += delta(mins[layer_idx,power,class_],
maxs[layer_idx,power,class_],
gram_features[layer_idx][power][class_][val])
if total_delta is None:
total_delta = class_deltas
else:
total_delta = torch.cat([total_delta,class_deltas],dim=0)
normalize_factors.append(total_delta.mean(dim=0,keepdim=True))
normalize_factors = torch.cat(normalize_factors,dim=1)
return mins, maxs, normalize_factors

def get_deviations(model, data, mins, maxs, normalize_factors, powers):
model.eval()

num_layer = 5 # 4 for lenet
num_poles_list = powers
exist = 1
pred_list = []
dev = [0 for x in range(data.shape[0])]
deviations = torch.zeros(data.shape[0],1)

# get predictions
logits, feature_list = model(data, return_feature_list=True)
confs = F.softmax(logits, dim=1).cpu().detach().numpy()
preds = np.argmax(confs, axis=1)
predsList = preds.tolist()
preds = torch.tensor(preds)

for pred in predsList:
exist = 1
if len(pred_list) == 0:
pred_list.extend([pred])
else:
for pred_now in pred_list:
if pred_now == pred:
exist = 0
if exist == 1:
pred_list.extend([pred])

# compute sample level deviation
for layer_idx in range(num_layer):
for pole_idx, p in enumerate(num_poles_list):
# get gram metirx
temp = feature_list[layer_idx].detach()
temp = temp**p
temp = temp.reshape(temp.shape[0], temp.shape[1], -1)
temp = ((torch.matmul(temp, temp.transpose(dim0=2,
dim1=1)))).sum(dim=2)
temp = (temp.sign() * torch.abs(temp)**(1 / p)).reshape(
temp.shape[0], -1)
temp = tensor2list(temp)

# compute the deviations with train data
for idx in range(len(temp)):
dev[idx] += (F.relu(mins[preds[idx]][layer_idx][pole_idx] -
sum(temp[idx])) /
torch.abs(mins[preds[idx]][layer_idx][pole_idx] +
10**-6)).sum()
dev[idx] += (F.relu(
sum(temp[idx]) - maxs[preds[idx]][layer_idx][pole_idx]) /
torch.abs(maxs[preds[idx]][layer_idx][pole_idx] +
10**-6)).sum()
conf = [i / 50 for i in dev]

return preds, torch.tensor(conf)
confs = F.softmax(logits, dim=1).cpu().detach()
confs, preds = confs.max(dim=1)
for layer_idx, feature in enumerate(feature_list):
n = normalize_factors[:,layer_idx].item()
for power in powers:
gram_feature = G_p(feature, power).cpu()
for class_ in range(logits.shape[1]):
deviations[preds==class_] += delta(mins[layer_idx,power,class_],
maxs[layer_idx,power,class_],
gram_feature[preds==class_])/n

return preds, -deviations/confs[:,None]