195 lines
8.1 KiB
Python
195 lines
8.1 KiB
Python
import math
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import os
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import time
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from copy import deepcopy
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import torch
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import torch.backends.cudnn as cudnn
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import torch.nn as nn
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import torch.nn.functional as F
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def init_seeds(seed=0):
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torch.manual_seed(seed)
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# Reduce randomness (may be slower on Tesla GPUs) # https://pytorch.org/docs/stable/notes/randomness.html
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if seed == 0:
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cudnn.deterministic = False
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cudnn.benchmark = True
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def select_device(device='', apex=False, batch_size=None):
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# device = 'cpu' or '0' or '0,1,2,3'
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cpu_request = device.lower() == 'cpu'
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if device and not cpu_request: # if device requested other than 'cpu'
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os.environ['CUDA_VISIBLE_DEVICES'] = device # set environment variable
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assert torch.cuda.is_available(), 'CUDA unavailable, invalid device %s requested' % device # check availablity
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cuda = False if cpu_request else torch.cuda.is_available()
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if cuda:
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c = 1024 ** 2 # bytes to MB
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ng = torch.cuda.device_count()
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if ng > 1 and batch_size: # check that batch_size is compatible with device_count
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assert batch_size % ng == 0, 'batch-size %g not multiple of GPU count %g' % (batch_size, ng)
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x = [torch.cuda.get_device_properties(i) for i in range(ng)]
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s = 'Using CUDA ' + ('Apex ' if apex else '') # apex for mixed precision https://github.com/NVIDIA/apex
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for i in range(0, ng):
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if i == 1:
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s = ' ' * len(s)
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print("%sdevice%g _CudaDeviceProperties(name='%s', total_memory=%dMB)" %
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(s, i, x[i].name, x[i].total_memory / c))
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else:
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print('Using CPU')
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print('') # skip a line
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return torch.device('cuda:0' if cuda else 'cpu')
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def time_synchronized():
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torch.cuda.synchronize() if torch.cuda.is_available() else None
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return time.time()
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def initialize_weights(model):
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for m in model.modules():
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t = type(m)
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if t is nn.Conv2d:
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pass # nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
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elif t is nn.BatchNorm2d:
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m.eps = 1e-4
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m.momentum = 0.03
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elif t in [nn.LeakyReLU, nn.ReLU, nn.ReLU6]:
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m.inplace = True
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def find_modules(model, mclass=nn.Conv2d):
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# finds layer indices matching module class 'mclass'
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return [i for i, m in enumerate(model.module_list) if isinstance(m, mclass)]
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def fuse_conv_and_bn(conv, bn):
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# https://tehnokv.com/posts/fusing-batchnorm-and-conv/
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with torch.no_grad():
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# init
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fusedconv = torch.nn.Conv2d(conv.in_channels,
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conv.out_channels,
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kernel_size=conv.kernel_size,
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stride=conv.stride,
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padding=conv.padding,
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bias=True)
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# prepare filters
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w_conv = conv.weight.clone().view(conv.out_channels, -1)
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w_bn = torch.diag(bn.weight.div(torch.sqrt(bn.eps + bn.running_var)))
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fusedconv.weight.copy_(torch.mm(w_bn, w_conv).view(fusedconv.weight.size()))
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# prepare spatial bias
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if conv.bias is not None:
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b_conv = conv.bias
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else:
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b_conv = torch.zeros(conv.weight.size(0))
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b_bn = bn.bias - bn.weight.mul(bn.running_mean).div(torch.sqrt(bn.running_var + bn.eps))
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fusedconv.bias.copy_(torch.mm(w_bn, b_conv.reshape(-1, 1)).reshape(-1) + b_bn)
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return fusedconv
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def model_info(model, verbose=False):
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# Plots a line-by-line description of a PyTorch model
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n_p = sum(x.numel() for x in model.parameters()) # number parameters
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n_g = sum(x.numel() for x in model.parameters() if x.requires_grad) # number gradients
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if verbose:
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print('%5s %40s %9s %12s %20s %10s %10s' % ('layer', 'name', 'gradient', 'parameters', 'shape', 'mu', 'sigma'))
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for i, (name, p) in enumerate(model.named_parameters()):
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name = name.replace('module_list.', '')
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print('%5g %40s %9s %12g %20s %10.3g %10.3g' %
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(i, name, p.requires_grad, p.numel(), list(p.shape), p.mean(), p.std()))
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try: # FLOPS
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from thop import profile
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macs, _ = profile(model, inputs=(torch.zeros(1, 3, 480, 640),), verbose=False)
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fs = ', %.1f GFLOPS' % (macs / 1E9 * 2)
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except:
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fs = ''
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print('Model Summary: %g layers, %g parameters, %g gradients%s' % (len(list(model.parameters())), n_p, n_g, fs))
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def load_classifier(name='resnet101', n=2):
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# Loads a pretrained model reshaped to n-class output
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import pretrainedmodels # https://github.com/Cadene/pretrained-models.pytorch#torchvision
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model = pretrainedmodels.__dict__[name](num_classes=1000, pretrained='imagenet')
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# Display model properties
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for x in ['model.input_size', 'model.input_space', 'model.input_range', 'model.mean', 'model.std']:
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print(x + ' =', eval(x))
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# Reshape output to n classes
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filters = model.last_linear.weight.shape[1]
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model.last_linear.bias = torch.nn.Parameter(torch.zeros(n))
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model.last_linear.weight = torch.nn.Parameter(torch.zeros(n, filters))
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model.last_linear.out_features = n
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return model
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def scale_img(img, ratio=1.0, same_shape=True): # img(16,3,256,416), r=ratio
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# scales img(bs,3,y,x) by ratio
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h, w = img.shape[2:]
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s = (int(h * ratio), int(w * ratio)) # new size
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img = F.interpolate(img, size=s, mode='bilinear', align_corners=False) # resize
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if not same_shape: # pad/crop img
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gs = 64 # (pixels) grid size
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h, w = [math.ceil(x * ratio / gs) * gs for x in (h, w)]
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return F.pad(img, [0, w - s[1], 0, h - s[0]], value=0.447) # value = imagenet mean
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class ModelEMA:
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""" Model Exponential Moving Average from https://github.com/rwightman/pytorch-image-models
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Keep a moving average of everything in the model state_dict (parameters and buffers).
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This is intended to allow functionality like
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https://www.tensorflow.org/api_docs/python/tf/train/ExponentialMovingAverage
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A smoothed version of the weights is necessary for some training schemes to perform well.
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E.g. Google's hyper-params for training MNASNet, MobileNet-V3, EfficientNet, etc that use
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RMSprop with a short 2.4-3 epoch decay period and slow LR decay rate of .96-.99 requires EMA
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smoothing of weights to match results. Pay attention to the decay constant you are using
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relative to your update count per epoch.
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To keep EMA from using GPU resources, set device='cpu'. This will save a bit of memory but
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disable validation of the EMA weights. Validation will have to be done manually in a separate
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process, or after the training stops converging.
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This class is sensitive where it is initialized in the sequence of model init,
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GPU assignment and distributed training wrappers.
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I've tested with the sequence in my own train.py for torch.DataParallel, apex.DDP, and single-GPU.
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"""
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def __init__(self, model, decay=0.9999, device=''):
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# make a copy of the model for accumulating moving average of weights
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self.ema = deepcopy(model)
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self.ema.eval()
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self.updates = 0 # number of EMA updates
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self.decay = lambda x: decay * (1 - math.exp(-x / 2000)) # decay exponential ramp (to help early epochs)
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self.device = device # perform ema on different device from model if set
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if device:
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self.ema.to(device=device)
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for p in self.ema.parameters():
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p.requires_grad_(False)
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def update(self, model):
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self.updates += 1
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d = self.decay(self.updates)
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with torch.no_grad():
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if type(model) in (nn.parallel.DataParallel, nn.parallel.DistributedDataParallel):
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msd, esd = model.module.state_dict(), self.ema.module.state_dict()
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else:
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msd, esd = model.state_dict(), self.ema.state_dict()
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for k, v in esd.items():
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if v.dtype.is_floating_point:
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v *= d
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v += (1. - d) * msd[k].detach()
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def update_attr(self, model):
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# Assign attributes (which may change during training)
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for k in model.__dict__.keys():
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if not k.startswith('_'):
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setattr(self.ema, k, getattr(model, k))
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