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- # Ultralytics 🚀 AGPL-3.0 License - https://ultralytics.com/license
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- """
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- Train a model on a dataset.
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-
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- Usage:
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- $ yolo mode=train model=yolo11n.pt data=coco8.yaml imgsz=640 epochs=100 batch=16
7
- """
8
-
9
- import gc
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- import math
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- import os
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- import subprocess
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- import time
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- import warnings
15
- from copy import copy, deepcopy
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- from datetime import datetime, timedelta
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- from pathlib import Path
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-
19
- import numpy as np
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- import torch
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- import torch.nn.functional as F
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- from torch import distributed as dist
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- from torch import nn, optim
24
-
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- from ultralytics import __version__
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- from ultralytics.cfg import get_cfg, get_save_dir
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- from ultralytics.data.utils import check_cls_dataset, check_det_dataset
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- from ultralytics.nn.tasks import attempt_load_one_weight, attempt_load_weights
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- from ultralytics.utils import (
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- DEFAULT_CFG,
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- LOCAL_RANK,
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- LOGGER,
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- RANK,
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- TQDM,
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- YAML,
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- callbacks,
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- clean_url,
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- colorstr,
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- emojis,
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- )
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- from ultralytics.utils.autobatch import check_train_batch_size
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- from ultralytics.utils.checks import check_amp, check_file, check_imgsz, check_model_file_from_stem, print_args
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- from ultralytics.utils.dist import ddp_cleanup, generate_ddp_command
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- from ultralytics.utils.files import get_latest_run
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- from ultralytics.utils.torch_utils import (
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- TORCH_2_4,
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- EarlyStopping,
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- ModelEMA,
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- autocast,
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- convert_optimizer_state_dict_to_fp16,
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- init_seeds,
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- one_cycle,
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- select_device,
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- strip_optimizer,
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- torch_distributed_zero_first,
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- unset_deterministic,
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- )
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-
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- class CWDLoss(nn.Module):
60
- """PyTorch version of `Channel-wise Distillation for Semantic Segmentation.
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- <https://arxiv.org/abs/2011.13256>`_.
62
- """
63
-
64
- def __init__(self, channels_s, channels_t, tau=1.0):
65
- super().__init__()
66
- self.tau = tau
67
-
68
- def forward(self, y_s, y_t):
69
- """Forward computation.
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- Args:
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- y_s (list): The student model prediction with
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- shape (N, C, H, W) in list.
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- y_t (list): The teacher model prediction with
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- shape (N, C, H, W) in list.
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- Return:
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- torch.Tensor: The calculated loss value of all stages.
77
- """
78
- assert len(y_s) == len(y_t)
79
- losses = []
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-
81
- for idx, (s, t) in enumerate(zip(y_s, y_t)):
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- assert s.shape == t.shape
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- N, C, H, W = s.shape
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-
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- # normalize in channel dimension
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- softmax_pred_T = F.softmax(t.view(-1, W * H) / self.tau, dim=1)
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-
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- logsoftmax = torch.nn.LogSoftmax(dim=1)
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- cost = torch.sum(
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- softmax_pred_T * logsoftmax(t.view(-1, W * H) / self.tau) -
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- softmax_pred_T * logsoftmax(s.view(-1, W * H) / self.tau)) * (self.tau ** 2)
92
-
93
- losses.append(cost / (C * N))
94
- loss = sum(losses)
95
- return loss
96
-
97
- class MGDLoss(nn.Module):
98
- def __init__(self,
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- student_channels,
100
- teacher_channels,
101
- alpha_mgd=0.00002,
102
- lambda_mgd=0.65,
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- ):
104
- super(MGDLoss, self).__init__()
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- self.alpha_mgd = alpha_mgd
106
- self.lambda_mgd = lambda_mgd
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- device = 'cuda' if torch.cuda.is_available() else 'cpu'
108
-
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- self.generation = nn.ModuleList([
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- nn.Sequential(
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- nn.Conv2d(s_chan, t_chan, kernel_size=3, padding=1),
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- nn.ReLU(inplace=True),
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- nn.Conv2d(t_chan, t_chan, kernel_size=3, padding=1)
114
- ).to(device) for s_chan, t_chan in zip(student_channels, teacher_channels)
115
- ])
116
-
117
- def forward(self, y_s, y_t, layer=None):
118
- """Forward computation.
119
- Args:
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- y_s (list): The student model prediction with
121
- shape (N, C, H, W) in list.
122
- y_t (list): The teacher model prediction with
123
- shape (N, C, H, W) in list.
124
- Return:
125
- torch.Tensor: The calculated loss value of all stages.
126
- """
127
- losses = []
128
- for idx, (s, t) in enumerate(zip(y_s, y_t)):
129
- # print(s.shape)
130
- # print(t.shape)
131
- # assert s.shape == t.shape
132
- if layer == "outlayer":
133
- idx = -1
134
- losses.append(self.get_dis_loss(s, t, idx) * self.alpha_mgd)
135
- loss = sum(losses)
136
- return loss
137
-
138
- def get_dis_loss(self, preds_S, preds_T, idx):
139
- loss_mse = nn.MSELoss(reduction='sum')
140
- N, C, H, W = preds_T.shape
141
-
142
- device = preds_S.device
143
- mat = torch.rand((N, 1, H, W)).to(device)
144
- mat = torch.where(mat > 1 - self.lambda_mgd, 0, 1).to(device)
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-
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- masked_fea = torch.mul(preds_S, mat)
147
- new_fea = self.generation[idx](masked_fea)
148
-
149
- dis_loss = loss_mse(new_fea, preds_T) / N
150
- return dis_loss
151
-
152
-
153
- class FeatureLoss(nn.Module):
154
- def __init__(self, channels_s, channels_t, distiller='mgd', loss_weight=1.0):
155
- super(FeatureLoss, self).__init__()
156
- self.loss_weight = loss_weight
157
- self.distiller = distiller
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-
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- # Move all modules to same precision
160
- device = 'cuda' if torch.cuda.is_available() else 'cpu'
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-
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- # Convert to ModuleList and ensure consistent dtype
163
- self.align_module = nn.ModuleList()
164
- self.norm = nn.ModuleList()
165
- self.norm1 = nn.ModuleList()
166
-
167
- # Create alignment modules
168
- for s_chan, t_chan in zip(channels_s, channels_t):
169
- align = nn.Sequential(
170
- nn.Conv2d(s_chan, t_chan, kernel_size=1, stride=1, padding=0),
171
- nn.BatchNorm2d(t_chan, affine=False)
172
- ).to(device)
173
- self.align_module.append(align)
174
-
175
- # Create normalization layers
176
- for t_chan in channels_t:
177
- self.norm.append(nn.BatchNorm2d(t_chan, affine=False).to(device))
178
-
179
- for s_chan in channels_s:
180
- self.norm1.append(nn.BatchNorm2d(s_chan, affine=False).to(device))
181
-
182
- if distiller == 'mgd':
183
- self.feature_loss = MGDLoss(channels_s, channels_t)
184
- elif distiller == 'cwd':
185
- self.feature_loss = CWDLoss(channels_s, channels_t)
186
- else:
187
- raise NotImplementedError
188
-
189
- def forward(self, y_s, y_t):
190
- min_len = min(len(y_s), len(y_t))
191
- y_s = y_s[:min_len]
192
- y_t = y_t[:min_len]
193
-
194
- tea_feats = []
195
- stu_feats = []
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-
197
- for idx, (s, t) in enumerate(zip(y_s, y_t)):
198
- s = s.type(next(self.align_module[idx].parameters()).dtype)
199
- t = t.type(next(self.align_module[idx].parameters()).dtype)
200
-
201
- if self.distiller == "cwd":
202
- s = self.align_module[idx](s)
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- stu_feats.append(s)
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- tea_feats.append(t.detach())
205
- else:
206
- t = self.norm[idx](t) # ✅ Correct normalization
207
- stu_feats.append(s)
208
- tea_feats.append(t.detach())
209
-
210
- loss = self.feature_loss(stu_feats, tea_feats)
211
- return self.loss_weight * loss
212
-
213
-
214
- class DistillationLoss:
215
- def __init__(self, models, modelt, distiller="CWDLoss"):
216
- self.distiller = distiller
217
- self.layers = ["6", "8", "13", "16", "19", "22"]
218
- self.models = models
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- self.modelt = modelt
220
-
221
- device = 'cuda' if torch.cuda.is_available() else 'cpu'
222
- # ini warm up
223
- with torch.no_grad():
224
- dummy_input = torch.randn(1, 3, 640, 640)
225
- _ = self.models(dummy_input.to(device))
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- _ = self.modelt(dummy_input.to(device))
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-
228
- self.channels_s = []
229
- self.channels_t = []
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- self.teacher_module_pairs = []
231
- self.student_module_pairs = []
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- self.remove_handle = []
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-
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- self._find_layers()
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-
236
- self.distill_loss_fn = FeatureLoss(
237
- channels_s=self.channels_s,
238
- channels_t=self.channels_t,
239
- distiller=distiller[:3]
240
- )
241
-
242
- def _find_layers(self):
243
-
244
- self.channels_s = []
245
- self.channels_t = []
246
- self.teacher_module_pairs = []
247
- self.student_module_pairs = []
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-
249
- for name, ml in self.modelt.named_modules():
250
- if name is not None:
251
- name = name.split(".")
252
- # print(name)
253
-
254
- if name[0] != "model":
255
- continue
256
- if len(name) >= 3:
257
- if name[1] in self.layers:
258
- if "cv2" in name[2]:
259
- if hasattr(ml, 'conv'):
260
- self.channels_t.append(ml.conv.out_channels)
261
- self.teacher_module_pairs.append(ml)
262
- # print()
263
- for name, ml in self.models.named_modules():
264
- if name is not None:
265
- name = name.split(".")
266
- # print(name)
267
- if name[0] != "model":
268
- continue
269
- if len(name) >= 3:
270
- if name[1] in self.layers:
271
- if "cv2" in name[2]:
272
- if hasattr(ml, 'conv'):
273
- self.channels_s.append(ml.conv.out_channels)
274
- self.student_module_pairs.append(ml)
275
-
276
- nl = min(len(self.channels_s), len(self.channels_t))
277
- self.channels_s = self.channels_s[-nl:]
278
- self.channels_t = self.channels_t[-nl:]
279
- self.teacher_module_pairs = self.teacher_module_pairs[-nl:]
280
- self.student_module_pairs = self.student_module_pairs[-nl:]
281
-
282
- def register_hook(self):
283
- # Remove the existing hook if they exist
284
- self.remove_handle_()
285
-
286
- self.teacher_outputs = []
287
- self.student_outputs = []
288
-
289
- def make_student_hook(l):
290
- def forward_hook(m, input, output):
291
- if isinstance(output, torch.Tensor):
292
- out = output.clone() # Clone to ensure we don't modify the original
293
- l.append(out)
294
- else:
295
- l.append([o.clone() if isinstance(o, torch.Tensor) else o for o in output])
296
- return forward_hook
297
-
298
- def make_teacher_hook(l):
299
- def forward_hook(m, input, output):
300
- if isinstance(output, torch.Tensor):
301
- l.append(output.detach().clone()) # Detach and clone teacher outputs
302
- else:
303
- l.append([o.detach().clone() if isinstance(o, torch.Tensor) else o for o in output])
304
- return forward_hook
305
-
306
- for ml, ori in zip(self.teacher_module_pairs, self.student_module_pairs):
307
- self.remove_handle.append(ml.register_forward_hook(make_teacher_hook(self.teacher_outputs)))
308
- self.remove_handle.append(ori.register_forward_hook(make_student_hook(self.student_outputs)))
309
-
310
- def get_loss(self):
311
- if not self.teacher_outputs or not self.student_outputs:
312
- return torch.tensor(0.0, requires_grad=True)
313
-
314
- if len(self.teacher_outputs) != len(self.student_outputs):
315
- print(f"Warning: Mismatched outputs - Teacher: {len(self.teacher_outputs)}, Student: {len(self.student_outputs)}")
316
- return torch.tensor(0.0, requires_grad=True)
317
-
318
- quant_loss = self.distill_loss_fn(y_s=self.student_outputs, y_t=self.teacher_outputs)
319
-
320
- if self.distiller != 'cwd':
321
- quant_loss *= 0.3
322
-
323
- self.teacher_outputs.clear()
324
- self.student_outputs.clear()
325
-
326
- return quant_loss
327
-
328
- def remove_handle_(self):
329
- for rm in self.remove_handle:
330
- rm.remove()
331
- self.remove_handle.clear()
332
-
333
-
334
-
335
- class BaseTrainer:
336
- """
337
- A base class for creating trainers.
338
-
339
- This class provides the foundation for training YOLO models, handling the training loop, validation, checkpointing,
340
- and various training utilities. It supports both single-GPU and multi-GPU distributed training.
341
-
342
- Attributes:
343
- args (SimpleNamespace): Configuration for the trainer.
344
- validator (BaseValidator): Validator instance.
345
- model (nn.Module): Model instance.
346
- callbacks (defaultdict): Dictionary of callbacks.
347
- save_dir (Path): Directory to save results.
348
- wdir (Path): Directory to save weights.
349
- last (Path): Path to the last checkpoint.
350
- best (Path): Path to the best checkpoint.
351
- save_period (int): Save checkpoint every x epochs (disabled if < 1).
352
- batch_size (int): Batch size for training.
353
- epochs (int): Number of epochs to train for.
354
- start_epoch (int): Starting epoch for training.
355
- device (torch.device): Device to use for training.
356
- amp (bool): Flag to enable AMP (Automatic Mixed Precision).
357
- scaler (amp.GradScaler): Gradient scaler for AMP.
358
- data (str): Path to data.
359
- ema (nn.Module): EMA (Exponential Moving Average) of the model.
360
- resume (bool): Resume training from a checkpoint.
361
- lf (nn.Module): Loss function.
362
- scheduler (torch.optim.lr_scheduler._LRScheduler): Learning rate scheduler.
363
- best_fitness (float): The best fitness value achieved.
364
- fitness (float): Current fitness value.
365
- loss (float): Current loss value.
366
- tloss (float): Total loss value.
367
- loss_names (list): List of loss names.
368
- csv (Path): Path to results CSV file.
369
- metrics (dict): Dictionary of metrics.
370
- plots (dict): Dictionary of plots.
371
-
372
- Methods:
373
- train: Execute the training process.
374
- validate: Run validation on the test set.
375
- save_model: Save model training checkpoints.
376
- get_dataset: Get train and validation datasets.
377
- setup_model: Load, create, or download model.
378
- build_optimizer: Construct an optimizer for the model.
379
-
380
- Examples:
381
- Initialize a trainer and start training
382
- >>> trainer = BaseTrainer(cfg="config.yaml")
383
- >>> trainer.train()
384
- """
385
-
386
- def __init__(self, cfg=DEFAULT_CFG, overrides=None, _callbacks=None):
387
- """
388
- Initialize the BaseTrainer class.
389
-
390
- Args:
391
- cfg (str, optional): Path to a configuration file.
392
- overrides (dict, optional): Configuration overrides.
393
- _callbacks (list, optional): List of callback functions.
394
- """
395
- self.args = get_cfg(cfg, overrides)
396
- self.check_resume(overrides)
397
- self.device = select_device(self.args.device, self.args.batch)
398
- # Update "-1" devices so post-training val does not repeat search
399
- self.args.device = os.getenv("CUDA_VISIBLE_DEVICES") if "cuda" in str(self.device) else str(self.device)
400
- self.validator = None
401
- self.metrics = None
402
- self.plots = {}
403
-
404
- if overrides:
405
- self.teacher = overrides.get("teacher", None)
406
- self.loss_type = overrides.get("distillation_loss", None)
407
- if "teacher" in overrides:
408
- overrides.pop("teacher")
409
- if "distillation_loss" in overrides:
410
- overrides.pop("distillation_loss")
411
- else:
412
- self.loss_type = None
413
- self.teacher = None
414
-
415
- init_seeds(self.args.seed + 1 + RANK, deterministic=self.args.deterministic)
416
-
417
- # Dirs
418
- self.save_dir = get_save_dir(self.args)
419
- self.args.name = self.save_dir.name # update name for loggers
420
- self.wdir = self.save_dir / "weights" # weights dir
421
- if RANK in {-1, 0}:
422
- self.wdir.mkdir(parents=True, exist_ok=True) # make dir
423
- self.args.save_dir = str(self.save_dir)
424
- YAML.save(self.save_dir / "args.yaml", vars(self.args)) # save run args
425
- self.last, self.best = self.wdir / "last.pt", self.wdir / "best.pt" # checkpoint paths
426
- self.save_period = self.args.save_period
427
-
428
- self.batch_size = self.args.batch
429
- self.epochs = self.args.epochs or 100 # in case users accidentally pass epochs=None with timed training
430
- self.start_epoch = 0
431
- if RANK == -1:
432
- print_args(vars(self.args))
433
-
434
- # Device
435
- if self.device.type in {"cpu", "mps"}:
436
- self.args.workers = 0 # faster CPU training as time dominated by inference, not dataloading
437
-
438
- # Model and Dataset
439
- self.model = check_model_file_from_stem(self.args.model) # add suffix, i.e. yolo11n -> yolo11n.pt
440
- with torch_distributed_zero_first(LOCAL_RANK): # avoid auto-downloading dataset multiple times
441
- self.data = self.get_dataset()
442
-
443
- self.ema = None
444
-
445
- # Optimization utils init
446
- self.lf = None
447
- self.scheduler = None
448
-
449
- # Epoch level metrics
450
- self.best_fitness = None
451
- self.fitness = None
452
- self.loss = None
453
- self.tloss = None
454
- self.loss_names = ["Loss"]
455
- self.csv = self.save_dir / "results.csv"
456
- self.plot_idx = [0, 1, 2]
457
-
458
- # HUB
459
- self.hub_session = None
460
-
461
- # Callbacks
462
- self.callbacks = _callbacks or callbacks.get_default_callbacks()
463
- if RANK in {-1, 0}:
464
- callbacks.add_integration_callbacks(self)
465
-
466
- def add_callback(self, event: str, callback):
467
- """Append the given callback to the event's callback list."""
468
- self.callbacks[event].append(callback)
469
-
470
- def set_callback(self, event: str, callback):
471
- """Override the existing callbacks with the given callback for the specified event."""
472
- self.callbacks[event] = [callback]
473
-
474
- def run_callbacks(self, event: str):
475
- """Run all existing callbacks associated with a particular event."""
476
- for callback in self.callbacks.get(event, []):
477
- callback(self)
478
-
479
- def train(self):
480
- """Allow device='', device=None on Multi-GPU systems to default to device=0."""
481
- if isinstance(self.args.device, str) and len(self.args.device): # i.e. device='0' or device='0,1,2,3'
482
- world_size = len(self.args.device.split(","))
483
- elif isinstance(self.args.device, (tuple, list)): # i.e. device=[0, 1, 2, 3] (multi-GPU from CLI is list)
484
- world_size = len(self.args.device)
485
- elif self.args.device in {"cpu", "mps"}: # i.e. device='cpu' or 'mps'
486
- world_size = 0
487
- elif torch.cuda.is_available(): # i.e. device=None or device='' or device=number
488
- world_size = 1 # default to device 0
489
- else: # i.e. device=None or device=''
490
- world_size = 0
491
-
492
- # Run subprocess if DDP training, else train normally
493
- if world_size > 1 and "LOCAL_RANK" not in os.environ:
494
- # Argument checks
495
- if self.args.rect:
496
- LOGGER.warning("'rect=True' is incompatible with Multi-GPU training, setting 'rect=False'")
497
- self.args.rect = False
498
- if self.args.batch < 1.0:
499
- LOGGER.warning(
500
- "'batch<1' for AutoBatch is incompatible with Multi-GPU training, setting default 'batch=16'"
501
- )
502
- self.args.batch = 16
503
-
504
- # Command
505
- cmd, file = generate_ddp_command(world_size, self)
506
- try:
507
- LOGGER.info(f"{colorstr('DDP:')} debug command {' '.join(cmd)}")
508
- subprocess.run(cmd, check=True)
509
- except Exception as e:
510
- raise e
511
- finally:
512
- ddp_cleanup(self, str(file))
513
-
514
- else:
515
- self._do_train(world_size)
516
-
517
- def _setup_scheduler(self):
518
- """Initialize training learning rate scheduler."""
519
- if self.args.cos_lr:
520
- self.lf = one_cycle(1, self.args.lrf, self.epochs) # cosine 1->hyp['lrf']
521
- else:
522
- self.lf = lambda x: max(1 - x / self.epochs, 0) * (1.0 - self.args.lrf) + self.args.lrf # linear
523
- self.scheduler = optim.lr_scheduler.LambdaLR(self.optimizer, lr_lambda=self.lf)
524
-
525
- def _setup_ddp(self, world_size):
526
- """Initialize and set the DistributedDataParallel parameters for training."""
527
- torch.cuda.set_device(RANK)
528
- self.device = torch.device("cuda", RANK)
529
- # LOGGER.info(f'DDP info: RANK {RANK}, WORLD_SIZE {world_size}, DEVICE {self.device}')
530
- os.environ["TORCH_NCCL_BLOCKING_WAIT"] = "1" # set to enforce timeout
531
- dist.init_process_group(
532
- backend="nccl" if dist.is_nccl_available() else "gloo",
533
- timeout=timedelta(seconds=10800), # 3 hours
534
- rank=RANK,
535
- world_size=world_size,
536
- )
537
-
538
- def _setup_train(self, world_size):
539
- """Build dataloaders and optimizer on correct rank process."""
540
- # Model
541
- self.run_callbacks("on_pretrain_routine_start")
542
- ckpt = self.setup_model()
543
- self.model = self.model.to(self.device)
544
-
545
- # Load teacher model to device
546
- if self.teacher is not None:
547
- for k, v in self.teacher.named_parameters():
548
- v.requires_grad = True
549
- self.teacher = self.teacher.to(self.device)
550
-
551
- self.set_model_attributes()
552
-
553
- # Freeze layers
554
- freeze_list = (
555
- self.args.freeze
556
- if isinstance(self.args.freeze, list)
557
- else range(self.args.freeze)
558
- if isinstance(self.args.freeze, int)
559
- else []
560
- )
561
- always_freeze_names = [".dfl"] # always freeze these layers
562
- freeze_layer_names = [f"model.{x}." for x in freeze_list] + always_freeze_names
563
- self.freeze_layer_names = freeze_layer_names
564
- for k, v in self.model.named_parameters():
565
- # v.register_hook(lambda x: torch.nan_to_num(x)) # NaN to 0 (commented for erratic training results)
566
- if any(x in k for x in freeze_layer_names):
567
- LOGGER.info(f"Freezing layer '{k}'")
568
- v.requires_grad = False
569
- elif not v.requires_grad and v.dtype.is_floating_point: # only floating point Tensor can require gradients
570
- LOGGER.warning(
571
- f"setting 'requires_grad=True' for frozen layer '{k}'. "
572
- "See ultralytics.engine.trainer for customization of frozen layers."
573
- )
574
- v.requires_grad = True
575
-
576
- # Check AMP
577
- self.amp = torch.tensor(self.args.amp).to(self.device) # True or False
578
- if self.amp and RANK in {-1, 0}: # Single-GPU and DDP
579
- callbacks_backup = callbacks.default_callbacks.copy() # backup callbacks as check_amp() resets them
580
- self.amp = torch.tensor(check_amp(self.model), device=self.device)
581
- callbacks.default_callbacks = callbacks_backup # restore callbacks
582
- if RANK > -1 and world_size > 1: # DDP
583
- dist.broadcast(self.amp.int(), src=0) # broadcast from rank 0 to all other ranks; gloo errors with boolean
584
- self.amp = bool(self.amp) # as boolean
585
- self.scaler = (
586
- torch.amp.GradScaler("cuda", enabled=self.amp) if TORCH_2_4 else torch.cuda.amp.GradScaler(enabled=self.amp)
587
- )
588
- if world_size > 1:
589
- self.model = nn.parallel.DistributedDataParallel(self.model, device_ids=[RANK], find_unused_parameters=True)
590
- if self.teacher is not None:
591
- self.teacher = nn.parallel.DistributedDataParallel(self.teacher, device_ids=[RANK])
592
- temp = self.teacher.eval()
593
-
594
- # Check imgsz
595
- gs = max(int(self.model.stride.max() if hasattr(self.model, "stride") else 32), 32) # grid size (max stride)
596
- self.args.imgsz = check_imgsz(self.args.imgsz, stride=gs, floor=gs, max_dim=1)
597
- self.stride = gs # for multiscale training
598
-
599
- # Batch size
600
- if self.batch_size < 1 and RANK == -1: # single-GPU only, estimate best batch size
601
- self.args.batch = self.batch_size = self.auto_batch()
602
-
603
-
604
- # Dataloaders
605
- batch_size = self.batch_size // max(world_size, 1)
606
- self.train_loader = self.get_dataloader(
607
- self.data["train"], batch_size=batch_size, rank=LOCAL_RANK, mode="train"
608
- )
609
- if RANK in {-1, 0}:
610
- # Note: When training DOTA dataset, double batch size could get OOM on images with >2000 objects.
611
- self.test_loader = self.get_dataloader(
612
- self.data.get("val") or self.data.get("test"),
613
- batch_size=batch_size if self.args.task == "obb" else batch_size * 2,
614
- rank=-1,
615
- mode="val",
616
- )
617
- self.validator = self.get_validator()
618
- metric_keys = self.validator.metrics.keys + self.label_loss_items(prefix="val")
619
- self.metrics = dict(zip(metric_keys, [0] * len(metric_keys)))
620
- self.ema = ModelEMA(self.model)
621
- if self.args.plots:
622
- self.plot_training_labels()
623
-
624
- # Optimizer
625
- self.accumulate = max(round(self.args.nbs / self.batch_size), 1) # accumulate loss before optimizing
626
- weight_decay = self.args.weight_decay * self.batch_size * self.accumulate / self.args.nbs # scale weight_decay
627
- iterations = math.ceil(len(self.train_loader.dataset) / max(self.batch_size, self.args.nbs)) * self.epochs
628
- self.optimizer = self.build_optimizer(
629
- model=self.model,
630
- teacher=self.teacher,
631
- name=self.args.optimizer,
632
- lr=self.args.lr0,
633
- momentum=self.args.momentum,
634
- decay=weight_decay,
635
- iterations=iterations,
636
- )
637
- # Scheduler
638
- self._setup_scheduler()
639
- self.stopper, self.stop = EarlyStopping(patience=self.args.patience), False
640
- self.resume_training(ckpt)
641
- self.scheduler.last_epoch = self.start_epoch - 1 # do not move
642
- self.run_callbacks("on_pretrain_routine_end")
643
-
644
- def _do_train(self, world_size=1):
645
- """Train the model with the specified world size."""
646
- if world_size > 1:
647
- self._setup_ddp(world_size)
648
- self._setup_train(world_size)
649
-
650
- nb = len(self.train_loader) # number of batches
651
- nw = max(round(self.args.warmup_epochs * nb), 100) if self.args.warmup_epochs > 0 else -1 # warmup iterations
652
- last_opt_step = -1
653
- self.epoch_time = None
654
- self.epoch_time_start = time.time()
655
- self.train_time_start = time.time()
656
- self.run_callbacks("on_train_start")
657
- LOGGER.info(
658
- f"Image sizes {self.args.imgsz} train, {self.args.imgsz} val\n"
659
- f"Using {self.train_loader.num_workers * (world_size or 1)} dataloader workers\n"
660
- f"Logging results to {colorstr('bold', self.save_dir)}\n"
661
- f"Starting training for " + (f"{self.args.time} hours..." if self.args.time else f"{self.epochs} epochs...")
662
- )
663
- if self.args.close_mosaic:
664
- base_idx = (self.epochs - self.args.close_mosaic) * nb
665
- self.plot_idx.extend([base_idx, base_idx + 1, base_idx + 2])
666
-
667
- # make loss
668
- if self.teacher is not None:
669
- distillation_loss = DistillationLoss(self.model, self.teacher, distiller=self.loss_type)
670
-
671
- epoch = self.start_epoch
672
- self.optimizer.zero_grad() # zero any resumed gradients to ensure stability on train start
673
- while True:
674
- self.epoch = epoch
675
- self.run_callbacks("on_train_epoch_start")
676
- with warnings.catch_warnings():
677
- warnings.simplefilter("ignore") # suppress 'Detected lr_scheduler.step() before optimizer.step()'
678
- self.scheduler.step()
679
-
680
- self._model_train()
681
- if RANK != -1:
682
- self.train_loader.sampler.set_epoch(epoch)
683
- pbar = enumerate(self.train_loader)
684
- # Update dataloader attributes (optional)
685
- if epoch == (self.epochs - self.args.close_mosaic):
686
- self._close_dataloader_mosaic()
687
- self.train_loader.reset()
688
-
689
- if RANK in {-1, 0}:
690
- LOGGER.info(self.progress_string())
691
- pbar = TQDM(enumerate(self.train_loader), total=nb)
692
- self.tloss = None
693
- if self.teacher is not None:
694
- distillation_loss.register_hook()
695
- for i, batch in pbar:
696
- self.run_callbacks("on_train_batch_start")
697
- # Warmup
698
- ni = i + nb * epoch
699
- if ni <= nw:
700
- xi = [0, nw] # x interp
701
- self.accumulate = max(1, int(np.interp(ni, xi, [1, self.args.nbs / self.batch_size]).round()))
702
- for j, x in enumerate(self.optimizer.param_groups):
703
- # Bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
704
- x["lr"] = np.interp(
705
- ni, xi, [self.args.warmup_bias_lr if j == 0 else 0.0, x["initial_lr"] * self.lf(epoch)]
706
- )
707
- if "momentum" in x:
708
- x["momentum"] = np.interp(ni, xi, [self.args.warmup_momentum, self.args.momentum])
709
-
710
- # Forward
711
- with autocast(self.amp):
712
- batch = self.preprocess_batch(batch)
713
- loss, self.loss_items = self.model(batch)
714
- self.loss = loss.sum()
715
- if RANK != -1:
716
- self.loss *= world_size
717
- self.tloss = (
718
- (self.tloss * i + self.loss_items) / (i + 1) if self.tloss is not None else self.loss_items
719
- )
720
-
721
- # Add more distillation logic
722
- if self.teacher is not None:
723
- distill_weight = ((1 - math.cos(i * math.pi / len(self.train_loader))) / 2) * (0.1 - 1) + 1
724
- with torch.no_grad():
725
- pred = self.teacher(batch['img'])
726
-
727
- self.d_loss = distillation_loss.get_loss()
728
- self.d_loss *- distill_weight
729
- self.loss += self.d_loss
730
- # Backward
731
- self.scaler.scale(self.loss).backward()
732
-
733
- # Optimize - https://pytorch.org/docs/master/notes/amp_examples.html
734
- if ni - last_opt_step >= self.accumulate:
735
- self.optimizer_step()
736
- last_opt_step = ni
737
-
738
- # Timed stopping
739
- if self.args.time:
740
- self.stop = (time.time() - self.train_time_start) > (self.args.time * 3600)
741
- if RANK != -1: # if DDP training
742
- broadcast_list = [self.stop if RANK == 0 else None]
743
- dist.broadcast_object_list(broadcast_list, 0) # broadcast 'stop' to all ranks
744
- self.stop = broadcast_list[0]
745
- if self.stop: # training time exceeded
746
- break
747
-
748
- # Log
749
- if RANK in {-1, 0}:
750
- loss_length = self.tloss.shape[0] if len(self.tloss.shape) else 1
751
- pbar.set_description(
752
- ("%11s" * 2 + "%11.4g" * (2 + loss_length))
753
- % (
754
- f"{epoch + 1}/{self.epochs}",
755
- f"{self._get_memory():.3g}G", # (GB) GPU memory util
756
- *(self.tloss if loss_length > 1 else torch.unsqueeze(self.tloss, 0)), # losses
757
- batch["cls"].shape[0], # batch size, i.e. 8
758
- batch["img"].shape[-1], # imgsz, i.e 640
759
- )
760
- )
761
- self.run_callbacks("on_batch_end")
762
- if self.args.plots and ni in self.plot_idx:
763
- self.plot_training_samples(batch, ni)
764
-
765
- self.run_callbacks("on_train_batch_end")
766
-
767
- # More distillation logic
768
- if self.teacher is not None:
769
- distillation_loss.remove_handle_()
770
-
771
-
772
- self.lr = {f"lr/pg{ir}": x["lr"] for ir, x in enumerate(self.optimizer.param_groups)} # for loggers
773
- self.run_callbacks("on_train_epoch_end")
774
- if RANK in {-1, 0}:
775
- final_epoch = epoch + 1 >= self.epochs
776
- self.ema.update_attr(self.model, include=["yaml", "nc", "args", "names", "stride", "class_weights"])
777
-
778
- # Validation
779
- if self.args.val or final_epoch or self.stopper.possible_stop or self.stop:
780
- self._clear_memory(threshold=0.5) # prevent VRAM spike
781
- self.metrics, self.fitness = self.validate()
782
- self.save_metrics(metrics={**self.label_loss_items(self.tloss), **self.metrics, **self.lr})
783
- self.stop |= self.stopper(epoch + 1, self.fitness) or final_epoch
784
- if self.args.time:
785
- self.stop |= (time.time() - self.train_time_start) > (self.args.time * 3600)
786
-
787
- # Save model
788
- if self.args.save or final_epoch:
789
- self.save_model()
790
- self.run_callbacks("on_model_save")
791
-
792
- # Scheduler
793
- t = time.time()
794
- self.epoch_time = t - self.epoch_time_start
795
- self.epoch_time_start = t
796
- if self.args.time:
797
- mean_epoch_time = (t - self.train_time_start) / (epoch - self.start_epoch + 1)
798
- self.epochs = self.args.epochs = math.ceil(self.args.time * 3600 / mean_epoch_time)
799
- self._setup_scheduler()
800
- self.scheduler.last_epoch = self.epoch # do not move
801
- self.stop |= epoch >= self.epochs # stop if exceeded epochs
802
- self.run_callbacks("on_fit_epoch_end")
803
- self._clear_memory(0.5) # clear if memory utilization > 50%
804
-
805
- # Early Stopping
806
- if RANK != -1: # if DDP training
807
- broadcast_list = [self.stop if RANK == 0 else None]
808
- dist.broadcast_object_list(broadcast_list, 0) # broadcast 'stop' to all ranks
809
- self.stop = broadcast_list[0]
810
- if self.stop:
811
- break # must break all DDP ranks
812
- epoch += 1
813
-
814
- if RANK in {-1, 0}:
815
- # Do final val with best.pt
816
- seconds = time.time() - self.train_time_start
817
- LOGGER.info(f"\n{epoch - self.start_epoch + 1} epochs completed in {seconds / 3600:.3f} hours.")
818
- self.final_eval()
819
- if self.args.plots:
820
- self.plot_metrics()
821
- self.run_callbacks("on_train_end")
822
- self._clear_memory()
823
-
824
- # Distill logic
825
- if self.teacher is not None:
826
- distillation_loss.remove_handle_()
827
- unset_deterministic()
828
-
829
- self.run_callbacks("teardown")
830
-
831
- def auto_batch(self, max_num_obj=0):
832
- """Calculate optimal batch size based on model and device memory constraints."""
833
- return check_train_batch_size(
834
- model=self.model,
835
- imgsz=self.args.imgsz,
836
- amp=self.amp,
837
- batch=self.batch_size,
838
- max_num_obj=max_num_obj,
839
- ) # returns batch size
840
-
841
- def _get_memory(self, fraction=False):
842
- """Get accelerator memory utilization in GB or as a fraction of total memory."""
843
- memory, total = 0, 0
844
- if self.device.type == "mps":
845
- memory = torch.mps.driver_allocated_memory()
846
- if fraction:
847
- return __import__("psutil").virtual_memory().percent / 100
848
- elif self.device.type != "cpu":
849
- memory = torch.cuda.memory_reserved()
850
- if fraction:
851
- total = torch.cuda.get_device_properties(self.device).total_memory
852
- return ((memory / total) if total > 0 else 0) if fraction else (memory / 2**30)
853
-
854
- def _clear_memory(self, threshold: float = None):
855
- """Clear accelerator memory by calling garbage collector and emptying cache."""
856
- if threshold:
857
- assert 0 <= threshold <= 1, "Threshold must be between 0 and 1."
858
- if self._get_memory(fraction=True) <= threshold:
859
- return
860
- gc.collect()
861
- if self.device.type == "mps":
862
- torch.mps.empty_cache()
863
- elif self.device.type == "cpu":
864
- return
865
- else:
866
- torch.cuda.empty_cache()
867
-
868
- def read_results_csv(self):
869
- """Read results.csv into a dictionary using pandas."""
870
- import pandas as pd # scope for faster 'import ultralytics'
871
-
872
- return pd.read_csv(self.csv).to_dict(orient="list")
873
-
874
- def _model_train(self):
875
- """Set model in training mode."""
876
- self.model.train()
877
- # Freeze BN stat
878
- for n, m in self.model.named_modules():
879
- if any(filter(lambda f: f in n, self.freeze_layer_names)) and isinstance(m, nn.BatchNorm2d):
880
- m.eval()
881
-
882
- def save_model(self):
883
- """Save model training checkpoints with additional metadata."""
884
- import io
885
-
886
- # Serialize ckpt to a byte buffer once (faster than repeated torch.save() calls)
887
- buffer = io.BytesIO()
888
- torch.save(
889
- {
890
- "epoch": self.epoch,
891
- "best_fitness": self.best_fitness,
892
- "model": None, # resume and final checkpoints derive from EMA
893
- "ema": deepcopy(self.ema.ema).half(),
894
- "updates": self.ema.updates,
895
- "optimizer": convert_optimizer_state_dict_to_fp16(deepcopy(self.optimizer.state_dict())),
896
- "train_args": vars(self.args), # save as dict
897
- "train_metrics": {**self.metrics, **{"fitness": self.fitness}},
898
- "train_results": self.read_results_csv(),
899
- "date": datetime.now().isoformat(),
900
- "version": __version__,
901
- "license": "AGPL-3.0 (https://ultralytics.com/license)",
902
- "docs": "https://docs.ultralytics.com",
903
- },
904
- buffer,
905
- )
906
- serialized_ckpt = buffer.getvalue() # get the serialized content to save
907
-
908
- # Save checkpoints
909
- self.last.write_bytes(serialized_ckpt) # save last.pt
910
- if self.best_fitness == self.fitness:
911
- self.best.write_bytes(serialized_ckpt) # save best.pt
912
- if (self.save_period > 0) and (self.epoch % self.save_period == 0):
913
- (self.wdir / f"epoch{self.epoch}.pt").write_bytes(serialized_ckpt) # save epoch, i.e. 'epoch3.pt'
914
- # if self.args.close_mosaic and self.epoch == (self.epochs - self.args.close_mosaic - 1):
915
- # (self.wdir / "last_mosaic.pt").write_bytes(serialized_ckpt) # save mosaic checkpoint
916
-
917
- def get_dataset(self):
918
- """
919
- Get train and validation datasets from data dictionary.
920
-
921
- Returns:
922
- (dict): A dictionary containing the training/validation/test dataset and category names.
923
- """
924
- try:
925
- if self.args.task == "classify":
926
- data = check_cls_dataset(self.args.data)
927
- elif self.args.data.rsplit(".", 1)[-1] in {"yaml", "yml"} or self.args.task in {
928
- "detect",
929
- "segment",
930
- "pose",
931
- "obb",
932
- }:
933
- data = check_det_dataset(self.args.data)
934
- if "yaml_file" in data:
935
- self.args.data = data["yaml_file"] # for validating 'yolo train data=url.zip' usage
936
- except Exception as e:
937
- raise RuntimeError(emojis(f"Dataset '{clean_url(self.args.data)}' error ❌ {e}")) from e
938
- if self.args.single_cls:
939
- LOGGER.info("Overriding class names with single class.")
940
- data["names"] = {0: "item"}
941
- data["nc"] = 1
942
- return data
943
-
944
- def setup_model(self):
945
- """
946
- Load, create, or download model for any task.
947
-
948
- Returns:
949
- (dict): Optional checkpoint to resume training from.
950
- """
951
- if isinstance(self.model, torch.nn.Module): # if model is loaded beforehand. No setup needed
952
- return
953
-
954
- cfg, weights = self.model, None
955
- ckpt = None
956
- if str(self.model).endswith(".pt"):
957
- weights, ckpt = attempt_load_one_weight(self.model)
958
- cfg = weights.yaml
959
- elif isinstance(self.args.pretrained, (str, Path)):
960
- weights, _ = attempt_load_one_weight(self.args.pretrained)
961
- self.model = self.get_model(cfg=cfg, weights=weights, verbose=RANK == -1) # calls Model(cfg, weights)
962
- return ckpt
963
-
964
- def optimizer_step(self):
965
- """Perform a single step of the training optimizer with gradient clipping and EMA update."""
966
- self.scaler.unscale_(self.optimizer) # unscale gradients
967
- torch.nn.utils.clip_grad_norm_(self.model.parameters(), max_norm=10.0) # clip gradients
968
- self.scaler.step(self.optimizer)
969
- self.scaler.update()
970
- self.optimizer.zero_grad()
971
- if self.ema:
972
- self.ema.update(self.model)
973
-
974
- def preprocess_batch(self, batch):
975
- """Allow custom preprocessing model inputs and ground truths depending on task type."""
976
- return batch
977
-
978
- def validate(self):
979
- """
980
- Run validation on test set using self.validator.
981
-
982
- Returns:
983
- metrics (dict): Dictionary of validation metrics.
984
- fitness (float): Fitness score for the validation.
985
- """
986
- metrics = self.validator(self)
987
- fitness = metrics.pop("fitness", -self.loss.detach().cpu().numpy()) # use loss as fitness measure if not found
988
- if not self.best_fitness or self.best_fitness < fitness:
989
- self.best_fitness = fitness
990
- return metrics, fitness
991
-
992
- def get_model(self, cfg=None, weights=None, verbose=True):
993
- """Get model and raise NotImplementedError for loading cfg files."""
994
- raise NotImplementedError("This task trainer doesn't support loading cfg files")
995
-
996
- def get_validator(self):
997
- """Return a NotImplementedError when the get_validator function is called."""
998
- raise NotImplementedError("get_validator function not implemented in trainer")
999
-
1000
- def get_dataloader(self, dataset_path, batch_size=16, rank=0, mode="train"):
1001
- """Return dataloader derived from torch.data.Dataloader."""
1002
- raise NotImplementedError("get_dataloader function not implemented in trainer")
1003
-
1004
- def build_dataset(self, img_path, mode="train", batch=None):
1005
- """Build dataset."""
1006
- raise NotImplementedError("build_dataset function not implemented in trainer")
1007
-
1008
- def label_loss_items(self, loss_items=None, prefix="train"):
1009
- """
1010
- Return a loss dict with labelled training loss items tensor.
1011
-
1012
- Note:
1013
- This is not needed for classification but necessary for segmentation & detection
1014
- """
1015
- return {"loss": loss_items} if loss_items is not None else ["loss"]
1016
-
1017
- def set_model_attributes(self):
1018
- """Set or update model parameters before training."""
1019
- self.model.names = self.data["names"]
1020
-
1021
- def build_targets(self, preds, targets):
1022
- """Build target tensors for training YOLO model."""
1023
- pass
1024
-
1025
- def progress_string(self):
1026
- """Return a string describing training progress."""
1027
- return ""
1028
-
1029
- # TODO: may need to put these following functions into callback
1030
- def plot_training_samples(self, batch, ni):
1031
- """Plot training samples during YOLO training."""
1032
- pass
1033
-
1034
- def plot_training_labels(self):
1035
- """Plot training labels for YOLO model."""
1036
- pass
1037
-
1038
- def save_metrics(self, metrics):
1039
- """Save training metrics to a CSV file."""
1040
- keys, vals = list(metrics.keys()), list(metrics.values())
1041
- n = len(metrics) + 2 # number of cols
1042
- s = "" if self.csv.exists() else (("%s," * n % tuple(["epoch", "time"] + keys)).rstrip(",") + "\n") # header
1043
- t = time.time() - self.train_time_start
1044
- with open(self.csv, "a", encoding="utf-8") as f:
1045
- f.write(s + ("%.6g," * n % tuple([self.epoch + 1, t] + vals)).rstrip(",") + "\n")
1046
-
1047
- def plot_metrics(self):
1048
- """Plot and display metrics visually."""
1049
- pass
1050
-
1051
- def on_plot(self, name, data=None):
1052
- """Register plots (e.g. to be consumed in callbacks)."""
1053
- path = Path(name)
1054
- self.plots[path] = {"data": data, "timestamp": time.time()}
1055
-
1056
- def final_eval(self):
1057
- """Perform final evaluation and validation for object detection YOLO model."""
1058
- ckpt = {}
1059
- for f in self.last, self.best:
1060
- if f.exists():
1061
- if f is self.last:
1062
- ckpt = strip_optimizer(f)
1063
- elif f is self.best:
1064
- k = "train_results" # update best.pt train_metrics from last.pt
1065
- strip_optimizer(f, updates={k: ckpt[k]} if k in ckpt else None)
1066
- LOGGER.info(f"\nValidating {f}...")
1067
- self.validator.args.plots = self.args.plots
1068
- self.metrics = self.validator(model=f)
1069
- self.metrics.pop("fitness", None)
1070
- self.run_callbacks("on_fit_epoch_end")
1071
-
1072
- def check_resume(self, overrides):
1073
- """Check if resume checkpoint exists and update arguments accordingly."""
1074
- resume = self.args.resume
1075
- if resume:
1076
- try:
1077
- exists = isinstance(resume, (str, Path)) and Path(resume).exists()
1078
- last = Path(check_file(resume) if exists else get_latest_run())
1079
-
1080
- # Check that resume data YAML exists, otherwise strip to force re-download of dataset
1081
- ckpt_args = attempt_load_weights(last).args
1082
- if not isinstance(ckpt_args["data"], dict) and not Path(ckpt_args["data"]).exists():
1083
- ckpt_args["data"] = self.args.data
1084
-
1085
- resume = True
1086
- self.args = get_cfg(ckpt_args)
1087
- self.args.model = self.args.resume = str(last) # reinstate model
1088
- for k in (
1089
- "imgsz",
1090
- "batch",
1091
- "device",
1092
- "close_mosaic",
1093
- ): # allow arg updates to reduce memory or update device on resume
1094
- if k in overrides:
1095
- setattr(self.args, k, overrides[k])
1096
-
1097
- except Exception as e:
1098
- raise FileNotFoundError(
1099
- "Resume checkpoint not found. Please pass a valid checkpoint to resume from, "
1100
- "i.e. 'yolo train resume model=path/to/last.pt'"
1101
- ) from e
1102
- self.resume = resume
1103
-
1104
- def resume_training(self, ckpt):
1105
- """Resume YOLO training from given epoch and best fitness."""
1106
- if ckpt is None or not self.resume:
1107
- return
1108
- best_fitness = 0.0
1109
- start_epoch = ckpt.get("epoch", -1) + 1
1110
- if ckpt.get("optimizer", None) is not None:
1111
- self.optimizer.load_state_dict(ckpt["optimizer"]) # optimizer
1112
- best_fitness = ckpt["best_fitness"]
1113
- if self.ema and ckpt.get("ema"):
1114
- self.ema.ema.load_state_dict(ckpt["ema"].float().state_dict()) # EMA
1115
- self.ema.updates = ckpt["updates"]
1116
- assert start_epoch > 0, (
1117
- f"{self.args.model} training to {self.epochs} epochs is finished, nothing to resume.\n"
1118
- f"Start a new training without resuming, i.e. 'yolo train model={self.args.model}'"
1119
- )
1120
- LOGGER.info(f"Resuming training {self.args.model} from epoch {start_epoch + 1} to {self.epochs} total epochs")
1121
- if self.epochs < start_epoch:
1122
- LOGGER.info(
1123
- f"{self.model} has been trained for {ckpt['epoch']} epochs. Fine-tuning for {self.epochs} more epochs."
1124
- )
1125
- self.epochs += ckpt["epoch"] # finetune additional epochs
1126
- self.best_fitness = best_fitness
1127
- self.start_epoch = start_epoch
1128
- if start_epoch > (self.epochs - self.args.close_mosaic):
1129
- self._close_dataloader_mosaic()
1130
-
1131
- def _close_dataloader_mosaic(self):
1132
- """Update dataloaders to stop using mosaic augmentation."""
1133
- if hasattr(self.train_loader.dataset, "mosaic"):
1134
- self.train_loader.dataset.mosaic = False
1135
- if hasattr(self.train_loader.dataset, "close_mosaic"):
1136
- LOGGER.info("Closing dataloader mosaic")
1137
- self.train_loader.dataset.close_mosaic(hyp=copy(self.args))
1138
-
1139
- def build_optimizer(self, model, teacher=None, name="auto", lr=0.001, momentum=0.9, decay=1e-5, iterations=1e5):
1140
- """
1141
- Construct an optimizer for the given model.
1142
-
1143
- Args:
1144
- model (torch.nn.Module): The model for which to build an optimizer.
1145
- name (str, optional): The name of the optimizer to use. If 'auto', the optimizer is selected
1146
- based on the number of iterations.
1147
- lr (float, optional): The learning rate for the optimizer.
1148
- momentum (float, optional): The momentum factor for the optimizer.
1149
- decay (float, optional): The weight decay for the optimizer.
1150
- iterations (float, optional): The number of iterations, which determines the optimizer if
1151
- name is 'auto'.
1152
-
1153
- Returns:
1154
- (torch.optim.Optimizer): The constructed optimizer.
1155
- """
1156
- g = [], [], [] # optimizer parameter groups
1157
- bn = tuple(v for k, v in nn.__dict__.items() if "Norm" in k) # normalization layers, i.e. BatchNorm2d()
1158
- if name == "auto":
1159
- LOGGER.info(
1160
- f"{colorstr('optimizer:')} 'optimizer=auto' found, "
1161
- f"ignoring 'lr0={self.args.lr0}' and 'momentum={self.args.momentum}' and "
1162
- f"determining best 'optimizer', 'lr0' and 'momentum' automatically... "
1163
- )
1164
- nc = self.data.get("nc", 10) # number of classes
1165
- lr_fit = round(0.002 * 5 / (4 + nc), 6) # lr0 fit equation to 6 decimal places
1166
- name, lr, momentum = ("SGD", 0.01, 0.9) if iterations > 10000 else ("AdamW", lr_fit, 0.9)
1167
- self.args.warmup_bias_lr = 0.0 # no higher than 0.01 for Adam
1168
-
1169
- for module_name, module in model.named_modules():
1170
- for param_name, param in module.named_parameters(recurse=False):
1171
- fullname = f"{module_name}.{param_name}" if module_name else param_name
1172
- if "bias" in fullname: # bias (no decay)
1173
- g[2].append(param)
1174
- elif isinstance(module, bn) or "logit_scale" in fullname: # weight (no decay)
1175
- # ContrastiveHead and BNContrastiveHead included here with 'logit_scale'
1176
- g[1].append(param)
1177
- else: # weight (with decay)
1178
- g[0].append(param)
1179
-
1180
- if teacher is not None:
1181
- for v in teacher.modules():
1182
- if hasattr(v, 'bias') and isinstance(v.bias, nn.Parameter):
1183
- g[2].append(v.bias)
1184
- if isinstance(v, bn): # weight (no decay)
1185
- g[1].append(v.weight)
1186
- elif hasattr(v, 'weight') and isinstance(v.weight, nn.Parameter): # weight (with decay)
1187
- g[0].append(v.weight)
1188
- optimizers = {"Adam", "Adamax", "AdamW", "NAdam", "RAdam", "RMSProp", "SGD", "auto"}
1189
- name = {x.lower(): x for x in optimizers}.get(name.lower())
1190
- if name in {"Adam", "Adamax", "AdamW", "NAdam", "RAdam"}:
1191
- optimizer = getattr(optim, name, optim.Adam)(g[2], lr=lr, betas=(momentum, 0.999), weight_decay=0.0)
1192
- elif name == "RMSProp":
1193
- optimizer = optim.RMSprop(g[2], lr=lr, momentum=momentum)
1194
- elif name == "SGD":
1195
- optimizer = optim.SGD(g[2], lr=lr, momentum=momentum, nesterov=True)
1196
- else:
1197
- raise NotImplementedError(
1198
- f"Optimizer '{name}' not found in list of available optimizers {optimizers}. "
1199
- "Request support for addition optimizers at https://github.com/ultralytics/ultralytics."
1200
- )
1201
-
1202
- optimizer.add_param_group({"params": g[0], "weight_decay": decay}) # add g0 with weight_decay
1203
- optimizer.add_param_group({"params": g[1], "weight_decay": 0.0}) # add g1 (BatchNorm2d weights)
1204
- LOGGER.info(
1205
- f"{colorstr('optimizer:')} {type(optimizer).__name__}(lr={lr}, momentum={momentum}) with parameter groups "
1206
- f"{len(g[1])} weight(decay=0.0), {len(g[0])} weight(decay={decay}), {len(g[2])} bias(decay=0.0)"
1207
- )
1208
- return optimizer