334 lines
12 KiB
Python
334 lines
12 KiB
Python
import copy
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import os
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import random
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from functools import wraps
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import kornia.augmentation as augs
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import torch
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import torch.nn.functional as F
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import torchvision
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from PIL import Image
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from kornia import filters, apply_hflip
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from torch import nn
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from torchvision.transforms import ToTensor
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from data.byol_attachment import RandomApply
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from trainer.networks import register_model, create_model
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from utils.util import checkpoint, opt_get
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def default(val, def_val):
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return def_val if val is None else val
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def flatten(t):
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return t.reshape(t.shape[0], -1)
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def singleton(cache_key):
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def inner_fn(fn):
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@wraps(fn)
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def wrapper(self, *args, **kwargs):
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instance = getattr(self, cache_key)
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if instance is not None:
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return instance
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instance = fn(self, *args, **kwargs)
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setattr(self, cache_key, instance)
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return instance
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return wrapper
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return inner_fn
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def get_module_device(module):
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return next(module.parameters()).device
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def set_requires_grad(model, val):
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for p in model.parameters():
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p.requires_grad = val
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# Specialized augmentor class that applies a set of image transformations on points as well, allowing one to track
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# where a point in the src image is located in the dest image. Restricts transformation such that this is possible.
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class PointwiseAugmentor(nn.Module):
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def __init__(self, img_size=224):
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super().__init__()
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self.jitter = RandomApply(augs.ColorJitter(0.8, 0.8, 0.8, 0.2), p=0.8)
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self.gray = augs.RandomGrayscale(p=0.2)
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self.blur = RandomApply(filters.GaussianBlur2d((3, 3), (1.5, 1.5)), p=0.1)
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self.rrc = augs.RandomResizedCrop((img_size, img_size), same_on_batch=True)
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# Given a point in the source image, returns the same point in the source image, given the kornia RRC params.
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def rrc_on_point(self, src_point, params):
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dh, dw = params['dst'][:,2,1]-params['dst'][:,0,1], params['dst'][:,2,0] - params['dst'][:,0,0]
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sh, sw = params['src'][:,2,1]-params['src'][:,0,1], params['src'][:,2,0] - params['src'][:,0,0]
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scale_h, scale_w = sh.float() / dh.float(), sw.float() / dw.float()
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t, l = src_point[0] - params['src'][0,0,1], src_point[1] - params['src'][0,0,0]
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t = (t.float() / scale_h[0]).long()
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l = (l.float() / scale_w[0]).long()
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return torch.stack([t,l])
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def flip_on_point(self, pt, input):
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t, l = pt[0], pt[1]
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center = input.shape[-1] // 2
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return t, 2 * center - l
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def forward(self, x, point):
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d = self.jitter(x)
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d = self.gray(d)
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will_flip = random.random() > .5
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if will_flip:
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d = apply_hflip(d)
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point = self.flip_on_point(point, x)
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d = self.blur(d)
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invalid = True
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while invalid:
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params = self.rrc.generate_parameters(d.shape)
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potential = self.rrc_on_point(point, params)
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# '10' is an arbitrary number: we want to provide some margin. Making predictions at the very edge of an image is not very useful.
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if potential[0] <= 10 or potential[1] <= 10 or potential[0] > x.shape[-2]-10 or potential[1] > x.shape[-1]-10:
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continue
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d = self.rrc(d, params=params)
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point = potential
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invalid = False
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return d, point
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# loss fn
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def loss_fn(x, y):
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x = F.normalize(x, dim=-1, p=2)
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y = F.normalize(y, dim=-1, p=2)
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return 2 - 2 * (x * y).sum(dim=-1)
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# exponential moving average
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class EMA():
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def __init__(self, beta):
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super().__init__()
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self.beta = beta
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def update_average(self, old, new):
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if old is None:
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return new
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return old * self.beta + (1 - self.beta) * new
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def update_moving_average(ema_updater, ma_model, current_model):
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for current_params, ma_params in zip(current_model.parameters(), ma_model.parameters()):
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old_weight, up_weight = ma_params.data, current_params.data
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ma_params.data = ema_updater.update_average(old_weight, up_weight)
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# MLP class for projector and predictor
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class MLP(nn.Module):
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def __init__(self, dim, projection_size, hidden_size=4096):
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super().__init__()
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self.net = nn.Sequential(
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nn.Linear(dim, hidden_size),
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nn.BatchNorm1d(hidden_size),
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nn.ReLU(inplace=True),
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nn.Linear(hidden_size, projection_size)
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)
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def forward(self, x):
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x = flatten(x)
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return self.net(x)
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# A wrapper class for training against networks that do not collapse into a small-dimensioned latent.
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class StructuralMLP(nn.Module):
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def __init__(self, dim, projection_size, hidden_size=4096):
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super().__init__()
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b, c, h, w = dim
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flattened_dim = c * h // 4 * w // 4
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self.net = nn.Sequential(
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nn.Conv2d(c, c, kernel_size=3, padding=1, stride=2),
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nn.BatchNorm2d(c),
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nn.ReLU(inplace=True),
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nn.Conv2d(c, c, kernel_size=3, padding=1, stride=2),
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nn.BatchNorm2d(c),
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nn.ReLU(inplace=True),
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nn.Flatten(),
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nn.Linear(flattened_dim, hidden_size),
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nn.BatchNorm1d(hidden_size),
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nn.ReLU(inplace=True),
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nn.Linear(hidden_size, projection_size)
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)
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def forward(self, x):
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return self.net(x)
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# a wrapper class for the base neural network
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# will manage the interception of the hidden layer output
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# and pipe it into the projecter and predictor nets
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class NetWrapper(nn.Module):
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def __init__(self, net, projection_size, projection_hidden_size, layer=-2, use_structural_mlp=False):
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super().__init__()
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self.net = net
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self.layer = layer
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self.projector = None
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self.projection_size = projection_size
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self.projection_hidden_size = projection_hidden_size
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self.structural_mlp = use_structural_mlp
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self.hidden = None
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self.hook_registered = False
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def _find_layer(self):
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if type(self.layer) == str:
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modules = dict([*self.net.named_modules()])
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return modules.get(self.layer, None)
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elif type(self.layer) == int:
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children = [*self.net.children()]
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return children[self.layer]
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return None
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def _hook(self, _, __, output):
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self.hidden = output
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def _register_hook(self):
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layer = self._find_layer()
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assert layer is not None, f'hidden layer ({self.layer}) not found'
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handle = layer.register_forward_hook(self._hook)
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self.hook_registered = True
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@singleton('projector')
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def _get_projector(self, hidden):
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if self.structural_mlp:
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projector = StructuralMLP(hidden.shape, self.projection_size, self.projection_hidden_size)
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else:
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_, dim = hidden.flatten(1,-1).shape
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projector = MLP(dim, self.projection_size, self.projection_hidden_size)
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return projector.to(hidden)
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def get_representation(self, x, pt):
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if self.layer == -1:
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return self.net(x, pt)
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if not self.hook_registered:
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self._register_hook()
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unused = self.net(x, pt)
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hidden = self.hidden
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self.hidden = None
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assert hidden is not None, f'hidden layer {self.layer} never emitted an output'
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return hidden
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def forward(self, x, pt):
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representation = self.get_representation(x, pt)
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projector = self._get_projector(representation)
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projection = checkpoint(projector, representation)
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return projection
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class BYOL(nn.Module):
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def __init__(
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self,
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net,
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image_size,
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hidden_layer=-2,
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projection_size=256,
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projection_hidden_size=4096,
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moving_average_decay=0.99,
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use_momentum=True,
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structural_mlp=False,
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):
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super().__init__()
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self.online_encoder = NetWrapper(net, projection_size, projection_hidden_size, layer=hidden_layer,
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use_structural_mlp=structural_mlp)
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self.aug = PointwiseAugmentor(image_size)
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self.use_momentum = use_momentum
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self.target_encoder = None
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self.target_ema_updater = EMA(moving_average_decay)
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self.online_predictor = MLP(projection_size, projection_size, projection_hidden_size)
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# get device of network and make wrapper same device
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device = get_module_device(net)
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self.to(device)
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# send a mock image tensor to instantiate singleton parameters
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self.forward(torch.randn(2, 3, image_size, image_size, device=device))
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@singleton('target_encoder')
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def _get_target_encoder(self):
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target_encoder = copy.deepcopy(self.online_encoder)
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set_requires_grad(target_encoder, False)
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for p in target_encoder.parameters():
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p.DO_NOT_TRAIN = True
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return target_encoder
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def reset_moving_average(self):
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del self.target_encoder
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self.target_encoder = None
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def update_for_step(self, step, __):
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assert self.use_momentum, 'you do not need to update the moving average, since you have turned off momentum for the target encoder'
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assert self.target_encoder is not None, 'target encoder has not been created yet'
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update_moving_average(self.target_ema_updater, self.target_encoder, self.online_encoder)
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def get_debug_values(self, step, __):
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# In the BYOL paper, this is made to increase over time. Not yet implemented, but still logging the value.
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return {'target_ema_beta': self.target_ema_updater.beta}
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def visual_dbg(self, step, path):
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torchvision.utils.save_image(self.im1.cpu().float(), os.path.join(path, "%i_image1.png" % (step,)))
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torchvision.utils.save_image(self.im2.cpu().float(), os.path.join(path, "%i_image2.png" % (step,)))
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def forward(self, image):
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_, _, h, w = image.shape
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point = torch.randint(h//8, 7*h//8, (2,)).long().to(image.device)
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image_one, pt_one = self.aug(image, point)
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image_two, pt_two = self.aug(image, point)
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# Keep copies on hand for visual_dbg.
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self.im1 = image_one.detach().clone()
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self.im1[:,:,pt_one[0]-3:pt_one[0]+3,pt_one[1]-3:pt_one[1]+3] = 1
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self.im2 = image_two.detach().clone()
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self.im2[:,:,pt_two[0]-3:pt_two[0]+3,pt_two[1]-3:pt_two[1]+3] = 1
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online_proj_one = self.online_encoder(image_one, pt_one)
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online_proj_two = self.online_encoder(image_two, pt_two)
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online_pred_one = self.online_predictor(online_proj_one)
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online_pred_two = self.online_predictor(online_proj_two)
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with torch.no_grad():
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target_encoder = self._get_target_encoder() if self.use_momentum else self.online_encoder
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target_proj_one = target_encoder(image_one, pt_one).detach()
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target_proj_two = target_encoder(image_two, pt_two).detach()
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loss_one = loss_fn(online_pred_one, target_proj_two.detach())
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loss_two = loss_fn(online_pred_two, target_proj_one.detach())
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loss = loss_one + loss_two
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return loss.mean()
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if __name__ == '__main__':
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pa = PointwiseAugmentor(256)
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for j in range(100):
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t = ToTensor()(Image.open('E:\\4k6k\\datasets\\ns_images\\imagesets\\000001_152761.jpg')).unsqueeze(0).repeat(8,1,1,1)
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p = torch.randint(50,180,(2,))
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augmented, dp = pa(t, p)
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t, p = pa(t, p)
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t[:,:,p[0]-3:p[0]+3,p[1]-3:p[1]+3] = 0
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torchvision.utils.save_image(t, f"{j}_src.png")
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augmented[:,:,dp[0]-3:dp[0]+3,dp[1]-3:dp[1]+3] = 0
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torchvision.utils.save_image(augmented, f"{j}_dst.png")
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@register_model
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def register_pixel_local_byol(opt_net, opt):
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subnet = create_model(opt, opt_net['subnet'])
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return BYOL(subnet, opt_net['image_size'], opt_net['hidden_layer']) |