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from typing import Optional
import torch
import torch.nn as nn
from einops import rearrange
class MainModel(nn.Module):
def __init__(
self,
encoder,
decoder,
fc_dim: int,
volume_block_idx: int,
share_embed_head: bool,
pre_filter=None,
use_gem: bool = False,
gem_coef: Optional[float] = None,
use_gsm: bool = False,
map_portion: float = 0,
otsu_sel: bool = False,
otsu_portion: float = 1,
):
super().__init__()
self.encoder = encoder
self.decoder = decoder
self.use_gem = use_gem
self.gem_coef = gem_coef
self.use_gsm = use_gsm
self.map_portion = map_portion
assert self.map_portion <= 0.5, "Map_portion must be less than 0.5"
self.otsu_sel = otsu_sel
self.otsu_portion = otsu_portion
self.volume_block_idx = volume_block_idx
volume_in_channel = int(fc_dim * (2 ** (self.volume_block_idx - 3)))
volume_out_channel = volume_in_channel // 2
self.scale = volume_out_channel**0.5
self.share_embed_head = share_embed_head
self.proj_head1 = nn.Sequential(
nn.Conv2d(
volume_in_channel, volume_in_channel, kernel_size=1, stride=1, padding=0
),
nn.LeakyReLU(),
nn.Conv2d(
volume_in_channel,
volume_out_channel,
kernel_size=1,
stride=1,
padding=0,
),
)
if not share_embed_head:
self.proj_head2 = nn.Sequential(
nn.Conv2d(
volume_in_channel,
volume_in_channel,
kernel_size=1,
stride=1,
padding=0,
),
nn.LeakyReLU(),
nn.Conv2d(
volume_in_channel,
volume_out_channel,
kernel_size=1,
stride=1,
padding=0,
),
)
self.pre_filter = pre_filter
def forward(self, image, seg_size=None):
"""
for output maps, the return value is the raw logits
for consistency volume, the return value is the value after sigmoid
"""
bs = image.shape[0]
if self.pre_filter is not None:
image = self.pre_filter(image)
# get output map
encoder_feature = self.encoder(image, return_feature_maps=True)
output_map = self.decoder(encoder_feature, segSize=seg_size)
output_map = output_map.sigmoid()
# b, _, h, w = output_map.shape
# get image-level prediction
if self.use_gem:
mh, mw = output_map.shape[-2:]
image_pred = output_map.flatten(1)
image_pred = torch.linalg.norm(image_pred, ord=self.gem_coef, dim=1)
image_pred = image_pred / (mh * mw)
elif self.use_gsm:
image_pred = output_map.flatten(1)
weight = project_onto_l1_ball(image_pred, 1.0)
image_pred = (image_pred * weight).sum(1)
else:
if self.otsu_sel:
n_pixel = output_map.shape[-1] * output_map.shape[-2]
image_pred = output_map.flatten(1)
image_pred, _ = torch.sort(image_pred, dim=1)
tmp = []
for b in range(bs):
num_otsu_sel = get_otsu_k(image_pred[b, ...], sorted=True)
num_otsu_sel = max(num_otsu_sel, n_pixel // 2 + 1)
tpk = int(max(1, (n_pixel - num_otsu_sel) * self.otsu_portion))
topk_output = torch.topk(image_pred[b, ...], k=tpk, dim=0)[0]
tmp.append(topk_output.mean())
image_pred = torch.stack(tmp)
else:
if self.map_portion == 0:
image_pred = nn.functional.max_pool2d(
output_map, kernel_size=output_map.shape[-2:]
)
image_pred = image_pred.squeeze(1).squeeze(1).squeeze(1)
else:
n_pixel = output_map.shape[-1] * output_map.shape[-2]
k = int(max(1, int(self.map_portion * n_pixel)))
topk_output = torch.topk(output_map.flatten(1), k, dim=1)[0]
image_pred = topk_output.mean(1)
if seg_size is not None:
output_map = nn.functional.interpolate(
output_map, size=seg_size, mode="bilinear", align_corners=False
)
output_map = output_map.clamp(0, 1)
# compute consistency volume, 0 for consistency, and 1 for inconsistency
feature_map1 = self.proj_head1(encoder_feature[self.volume_block_idx])
if not self.share_embed_head:
feature_map2 = self.proj_head2(encoder_feature[self.volume_block_idx])
else:
feature_map2 = feature_map1.clone()
b, c, h, w = feature_map1.shape
feature_map1 = rearrange(feature_map1, "b c h w -> b c (h w)")
feature_map2 = rearrange(feature_map2, "b c h w -> b c (h w)")
consistency_volume = torch.bmm(feature_map1.transpose(-1, -2), feature_map2)
consistency_volume = rearrange(
consistency_volume, "b (h1 w1) (h2 w2) -> b h1 w1 h2 w2", h1=h, h2=h
)
consistency_volume = consistency_volume / self.scale
consistency_volume = 1 - consistency_volume.sigmoid()
vh, vw = consistency_volume.shape[-2:]
if self.use_gem:
volume_image_pred = consistency_volume.flatten(1)
volume_image_pred = torch.linalg.norm(
volume_image_pred, ord=self.gem_coef, dim=1
)
volume_image_pred = volume_image_pred / (vh * vw * vh * vw)
elif self.use_gsm:
volume_image_pred = consistency_volume.flatten(1)
weight = project_onto_l1_ball(volume_image_pred, 1.0)
volume_image_pred = (volume_image_pred * weight).sum(1)
else:
# FIXME skip Otsu's selection on volume due to its slowness
# if self.otsu_sel:
# n_ele = vh * vw * vh * vw
# volume_image_pred = consistency_volume.flatten(1)
# volume_image_pred, _ = torch.sort(volume_image_pred, dim=1)
# tmp = []
# for b in range(bs):
# num_otsu_sel = get_otsu_k(volume_image_pred[b, ...], sorted=True)
# num_otsu_sel = max(num_otsu_sel, n_ele // 2 + 1)
# tpk = int(max(1, (n_ele - num_otsu_sel) * self.otsu_portion))
# topk_output = torch.topk(volume_image_pred[b, ...], k=tpk, dim=0)[0]
# tmp.append(topk_output.mean())
# volume_image_pred = torch.stack(tmp)
# else:
if self.map_portion == 0:
volume_image_pred = torch.max(consistency_volume.flatten(1), dim=1)[0]
else:
n_ele = vh * vw * vh * vw
k = int(max(1, int(self.map_portion * n_ele)))
topk_output = torch.topk(consistency_volume.flatten(1), k, dim=1)[0]
volume_image_pred = topk_output.mean(1)
return {
"out_map": output_map,
"map_pred": image_pred,
"out_vol": consistency_volume,
"vol_pred": volume_image_pred,
}
def project_onto_l1_ball(x, eps):
"""
Compute Euclidean projection onto the L1 ball for a batch.
min ||x - u||_2 s.t. ||u||_1 <= eps
Inspired by the corresponding numpy version by Adrien Gaidon.
Parameters
----------
x: (batch_size, *) torch array
batch of arbitrary-size tensors to project, possibly on GPU
eps: float
radius of l-1 ball to project onto
Returns
-------
u: (batch_size, *) torch array
batch of projected tensors, reshaped to match the original
Notes
-----
The complexity of this algorithm is in O(dlogd) as it involves sorting x.
References
----------
[1] Efficient Projections onto the l1-Ball for Learning in High Dimensions
John Duchi, Shai Shalev-Shwartz, Yoram Singer, and Tushar Chandra.
International Conference on Machine Learning (ICML 2008)
"""
with torch.no_grad():
original_shape = x.shape
x = x.view(x.shape[0], -1)
mask = (torch.norm(x, p=1, dim=1) < eps).float().unsqueeze(1)
mu, _ = torch.sort(torch.abs(x), dim=1, descending=True)
cumsum = torch.cumsum(mu, dim=1)
arange = torch.arange(1, x.shape[1] + 1, device=x.device)
rho, _ = torch.max((mu * arange > (cumsum - eps)) * arange, dim=1)
theta = (cumsum[torch.arange(x.shape[0]), rho.cpu() - 1] - eps) / rho
proj = (torch.abs(x) - theta.unsqueeze(1)).clamp(min=0)
x = mask * x + (1 - mask) * proj * torch.sign(x)
x = x.view(original_shape)
return x
def get_otsu_k(attention, return_value=False, sorted=False):
def _get_weighted_var(seq, pivot: int):
# seq is of shape [t], in ascending order
length = seq.shape[0]
wb = pivot / length
vb = seq[:pivot].var()
wf = 1 - pivot / length
vf = seq[pivot:].var()
return wb * vb + wf * vf
# attention shape: t
# TODO use half
length = attention.shape[0]
if length == 1:
return 0
elif length == 2:
return 1
if not sorted:
attention, _ = torch.sort(attention)
optimal_i = length // 2
min_intra_class_var = _get_weighted_var(attention, optimal_i)
# for i in range(1, length):
# intra_class_var = _get_weighted_var(attention, i)
# if intra_class_var < min_intra_class_var:
# min_intra_class_var = intra_class_var
# optimal_i = i
got_it = False
# look left
for i in range(optimal_i - 1, 0, -1):
intra_class_var = _get_weighted_var(attention, i)
if intra_class_var > min_intra_class_var:
break
else:
min_intra_class_var = intra_class_var
optimal_i = i
got_it = True
# look right
if not got_it:
for i in range(optimal_i + 1, length):
intra_class_var = _get_weighted_var(attention, i)
if intra_class_var > min_intra_class_var:
break
else:
min_intra_class_var = intra_class_var
optimal_i = i
if return_value:
return attention[optimal_i]
else:
return optimal_i
if __name__ == "__main__":
model = MainModel(None, None, 1024, 2, True, "srm")
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