Skip to content

model_trainer

sleap_nn.training.model_trainer

This module is to train a sleap-nn model using Lightning.

Classes:

Name Description
ModelTrainer

Train sleap-nn model using PyTorch Lightning.

ModelTrainer

Train sleap-nn model using PyTorch Lightning.

This class is used to create dataloaders, train a sleap-nn model and save the model checkpoints/ logs with options to logging with wandb and csvlogger.

Parameters:

Name Type Description Default
config

OmegaConf dictionary which has the following: (i) data_config: data loading pre-processing configs. (ii) model_config: backbone and head configs to be passed to Model class. (iii) trainer_config: trainer configs like accelerator, optimiser params, etc.

required
train_labels

List of sio.Labels objects for training dataset.

required
val_labels

List of sio.Labels objects for validation dataset.

required
skeletons

List of sio.Skeleton objects in a single slp file.

required
lightning_model

One of the child classes of sleap_nn.training.lightning_modules.LightningModel.

required
model_type

Type of the model. One of single_instance, centered_instance, centroid, bottomup, multi_class_bottomup, multi_class_topdown.

required
backbone_type

Backbone model. One of unet, convnext and swint.

required
trainer

Instance of the lightning.Trainer initialized with loggers and callbacks.

required

Methods:

Name Description
get_model_trainer_from_config

Create a model trainer instance from config.

setup_config

Compute config parameters.

train

Train the lightning model.

Source code in sleap_nn/training/model_trainer.py
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
@attrs.define
class ModelTrainer:
    """Train sleap-nn model using PyTorch Lightning.

    This class is used to create dataloaders, train a sleap-nn model and save the model checkpoints/ logs with options to logging
    with wandb and csvlogger.

    Args:
        config: OmegaConf dictionary which has the following:
                (i) data_config: data loading pre-processing configs.
                (ii) model_config: backbone and head configs to be passed to `Model` class.
                (iii) trainer_config: trainer configs like accelerator, optimiser params, etc.
        train_labels: List of `sio.Labels` objects for training dataset.
        val_labels: List of `sio.Labels` objects for validation dataset.
        skeletons: List of `sio.Skeleton` objects in a single slp file.
        lightning_model: One of the child classes of `sleap_nn.training.lightning_modules.LightningModel`.
        model_type: Type of the model. One of `single_instance`, `centered_instance`, `centroid`, `bottomup`, `multi_class_bottomup`, `multi_class_topdown`.
        backbone_type: Backbone model. One of `unet`, `convnext` and `swint`.
        trainer: Instance of the `lightning.Trainer` initialized with loggers and callbacks.
    """

    config: DictConfig
    _initial_config: Optional[DictConfig] = None
    train_labels: List[sio.Labels] = attrs.field(factory=list)
    val_labels: List[sio.Labels] = attrs.field(factory=list)
    skeletons: Optional[List[sio.Skeleton]] = None

    lightning_model: Optional[LightningModel] = None
    model_type: Optional[str] = None
    backbone_type: Optional[str] = None

    _profilers: dict = {
        "advanced": AdvancedProfiler(),
        "passthrough": PassThroughProfiler(),
        "pytorch": PyTorchProfiler(),
        "simple": SimpleProfiler(),
    }

    trainer: Optional[L.Trainer] = None

    @classmethod
    def get_model_trainer_from_config(
        cls,
        config: DictConfig,
        train_labels: Optional[List[sio.Labels]] = None,
        val_labels: Optional[List[sio.Labels]] = None,
    ):
        """Create a model trainer instance from config."""
        # Verify config structure.
        config = verify_training_cfg(config)

        model_trainer = cls(config=config)

        model_trainer.model_type = get_model_type_from_cfg(model_trainer.config)
        model_trainer.backbone_type = get_backbone_type_from_cfg(model_trainer.config)

        if model_trainer.config.trainer_config.seed is not None:
            model_trainer._set_seed()

        if train_labels is None and val_labels is None:
            # read labels from paths provided in the config
            train_labels = [
                sio.load_slp(path)
                for path in model_trainer.config.data_config.train_labels_path
            ]
            val_labels = (
                [
                    sio.load_slp(path)
                    for path in model_trainer.config.data_config.val_labels_path
                ]
                if model_trainer.config.data_config.val_labels_path is not None
                else None
            )
            model_trainer._setup_train_val_labels(
                labels=train_labels, val_labels=val_labels
            )
        else:
            model_trainer._setup_train_val_labels(
                labels=train_labels, val_labels=val_labels
            )

        model_trainer._initial_config = model_trainer.config.copy()
        # update config parameters
        model_trainer.setup_config()

        # Check if all videos exist across all labels
        all_videos_exist = all(
            video.exists(check_all=True)
            for labels in [*model_trainer.train_labels, *model_trainer.val_labels]
            for video in labels.videos
        )

        if not all_videos_exist:
            raise FileNotFoundError(
                "One or more video files do not exist or are not accessible."
            )

        return model_trainer

    def _set_seed(self):
        """Set seed for the current experiment."""
        seed = self.config.trainer_config.seed

        random.seed(seed)

        # torch
        torch.manual_seed(seed)

        # if cuda is available
        if torch.cuda.is_available():
            torch.cuda.manual_seed(seed)

        # lightning
        L.seed_everything(seed)

        # numpy
        np.random.seed(seed)

    def _get_trainer_devices(self):
        """Get trainer devices."""
        trainer_devices = (
            self.config.trainer_config.trainer_devices
            if self.config.trainer_config.trainer_devices is not None
            else "auto"
        )
        if (
            trainer_devices == "auto"
            and OmegaConf.select(
                self.config, "trainer_config.trainer_device_indices", default=None
            )
            is not None
        ):
            trainer_devices = len(
                OmegaConf.select(
                    self.config,
                    "trainer_config.trainer_device_indices",
                    default=None,
                )
            )
        elif trainer_devices == "auto":
            if torch.cuda.is_available():
                trainer_devices = torch.cuda.device_count()
            elif torch.backends.mps.is_available():
                trainer_devices = 1
            elif torch.xpu.is_available():
                trainer_devices = torch.xpu.device_count()
            else:
                trainer_devices = 1
        return trainer_devices

    def _count_labeled_frames(
        self, labels_list: List[sio.Labels], user_only: bool = True
    ) -> int:
        """Count labeled frames, optionally filtering to user-labeled only.

        Args:
            labels_list: List of Labels objects to count frames from.
            user_only: If True, count only frames with user instances.

        Returns:
            Total count of labeled frames.
        """
        total = 0
        for label in labels_list:
            if user_only:
                total += sum(1 for lf in label if lf.has_user_instances)
            else:
                total += len(label)
        return total

    def _filter_to_user_labeled(self, labels: sio.Labels) -> sio.Labels:
        """Filter a Labels object to only include user-labeled frames.

        Args:
            labels: Labels object to filter.

        Returns:
            New Labels object containing only frames with user instances.
        """
        # Filter labeled frames to only those with user instances
        user_lfs = [lf for lf in labels if lf.has_user_instances]

        # Set instances to user instances only
        for lf in user_lfs:
            lf.instances = lf.user_instances

        # Create new Labels with filtered frames
        return sio.Labels(
            labeled_frames=user_lfs,
            videos=labels.videos,
            skeletons=labels.skeletons,
            tracks=labels.tracks,
            suggestions=labels.suggestions,
            provenance=labels.provenance,
        )

    def _setup_train_val_labels(
        self,
        labels: Optional[List[sio.Labels]] = None,
        val_labels: Optional[List[sio.Labels]] = None,
    ):
        """Create train and val labels objects. (Initialize `self.train_labels` and `self.val_labels`)."""
        logger.info(f"Creating train-val split...")
        total_train_lfs = 0
        total_val_lfs = 0
        self.skeletons = labels[0].skeletons

        # Check if we should count only user-labeled frames
        user_instances_only = OmegaConf.select(
            self.config, "data_config.user_instances_only", default=True
        )

        # check if all `.slp` file shave same skeleton structure (if multiple slp file paths are provided)
        skeleton = self.skeletons[0]
        for index, train_label in enumerate(labels):
            skel_temp = train_label.skeletons[0]
            skeletons_equal = skeleton.matches(skel_temp)
            if not skeletons_equal:
                message = f"The skeletons in the training labels: {index + 1} do not match the skeleton in the first training label file."
                logger.error(message)
                raise ValueError(message)

        # Check for same-data mode (train = val, for intentional overfitting)
        use_same = OmegaConf.select(
            self.config, "data_config.use_same_data_for_val", default=False
        )

        if use_same:
            # Same mode: use identical data for train and val (for overfitting)
            logger.info("Using same data for train and val (overfit mode)")
            self.train_labels = labels
            self.val_labels = labels
            total_train_lfs = self._count_labeled_frames(labels, user_instances_only)
            total_val_lfs = total_train_lfs
        elif val_labels is None or not len(val_labels):
            # if val labels are not provided, split from train
            val_fraction = OmegaConf.select(
                self.config, "data_config.validation_fraction", default=0.1
            )
            seed = (
                42
                if (
                    self.config.trainer_config.seed is None
                    and self._get_trainer_devices() > 1
                )
                else self.config.trainer_config.seed
            )
            for label in labels:
                train_split, val_split = label.make_training_splits(
                    n_train=1 - val_fraction, n_val=val_fraction, seed=seed
                )
                self.train_labels.append(train_split)
                self.val_labels.append(val_split)
                # make_training_splits returns only user-labeled frames
                total_train_lfs += len(train_split)
                total_val_lfs += len(val_split)
        else:
            self.train_labels = labels
            self.val_labels = val_labels
            total_train_lfs = self._count_labeled_frames(labels, user_instances_only)
            total_val_lfs = self._count_labeled_frames(val_labels, user_instances_only)

        logger.info(f"# Train Labeled frames: {total_train_lfs}")
        logger.info(f"# Val Labeled frames: {total_val_lfs}")

    def _setup_preprocessing_config(self):
        """Setup preprocessing config."""
        # compute max_heigt, max_width, and crop_size (if not provided in the config)
        max_height = self.config.data_config.preprocessing.max_height
        max_width = self.config.data_config.preprocessing.max_width
        if (
            self.model_type == "centered_instance"
            or self.model_type == "multi_class_topdown"
        ):
            crop_size = self.config.data_config.preprocessing.crop_size

        max_h, max_w = 0, 0
        max_crop_size = 0

        for train_label in self.train_labels:
            # compute max h and w from slp file if not provided
            if max_height is None or max_width is None:
                current_max_h, current_max_w = get_max_height_width(train_label)

                if current_max_h > max_h:
                    max_h = current_max_h
                if current_max_w > max_w:
                    max_w = current_max_w

            if (
                self.model_type == "centered_instance"
                or self.model_type == "multi_class_topdown"
            ):
                # compute crop size if not provided in config
                if crop_size is None:
                    # Get padding from config or auto-compute from augmentation settings
                    padding = self.config.data_config.preprocessing.crop_padding
                    if padding is None:
                        # Auto-compute padding based on augmentation settings
                        aug_config = self.config.data_config.augmentation_config
                        if (
                            self.config.data_config.use_augmentations_train
                            and aug_config is not None
                            and aug_config.geometric is not None
                        ):
                            geo = aug_config.geometric
                            # Check if rotation is enabled (via rotation_p or affine_p)
                            rotation_enabled = (
                                geo.rotation_p is not None and geo.rotation_p > 0
                            ) or (
                                geo.rotation_p is None
                                and geo.scale_p is None
                                and geo.translate_p is None
                                and geo.affine_p > 0
                            )
                            # Check if scale is enabled (via scale_p or affine_p)
                            scale_enabled = (
                                geo.scale_p is not None and geo.scale_p > 0
                            ) or (
                                geo.rotation_p is None
                                and geo.scale_p is None
                                and geo.translate_p is None
                                and geo.affine_p > 0
                            )

                            if rotation_enabled or scale_enabled:
                                # First find the actual max bbox size from labels
                                bbox_size = find_max_instance_bbox_size(train_label)
                                bbox_size = max(
                                    bbox_size,
                                    self.config.data_config.preprocessing.min_crop_size
                                    or 100,
                                )
                                rotation_max = (
                                    max(
                                        abs(geo.rotation_min),
                                        abs(geo.rotation_max),
                                    )
                                    if rotation_enabled
                                    else 0.0
                                )
                                scale_max = geo.scale_max if scale_enabled else 1.0
                                padding = compute_augmentation_padding(
                                    bbox_size=bbox_size,
                                    rotation_max=rotation_max,
                                    scale_max=scale_max,
                                )
                            else:
                                padding = 0
                        else:
                            padding = 0

                    crop_sz = find_instance_crop_size(
                        labels=train_label,
                        padding=padding,
                        maximum_stride=self.config.model_config.backbone_config[
                            f"{self.backbone_type}"
                        ]["max_stride"],
                        min_crop_size=self.config.data_config.preprocessing.min_crop_size,
                    )

                    if crop_sz > max_crop_size:
                        max_crop_size = crop_sz

        # if preprocessing params were None, replace with computed params
        if max_height is None or max_width is None:
            self.config.data_config.preprocessing.max_height = max_h
            self.config.data_config.preprocessing.max_width = max_w

        if (
            self.model_type == "centered_instance"
            or self.model_type == "multi_class_topdown"
        ) and crop_size is None:
            self.config.data_config.preprocessing.crop_size = max_crop_size

    def _setup_head_config(self):
        """Setup node, edge and class names in head config."""
        # if edges and part names aren't set in head configs, get it from labels object.
        head_config = self.config.model_config.head_configs[self.model_type]
        for key in head_config:
            if "part_names" in head_config[key].keys():
                if head_config[key]["part_names"] is None:
                    self.config.model_config.head_configs[self.model_type][key][
                        "part_names"
                    ] = self.skeletons[0].node_names

            if "edges" in head_config[key].keys():
                if head_config[key]["edges"] is None:
                    edges = [
                        (x.source.name, x.destination.name)
                        for x in self.skeletons[0].edges
                    ]
                    self.config.model_config.head_configs[self.model_type][key][
                        "edges"
                    ] = edges

            if "classes" in head_config[key].keys():
                if head_config[key]["classes"] is None:
                    tracks = []
                    for train_label in self.train_labels:
                        tracks.extend(
                            [x.name for x in train_label.tracks if x is not None]
                        )
                    classes = list(set(tracks))
                    if not len(classes):
                        message = (
                            f"No tracks found. ID models need tracks to be defined."
                        )
                        logger.error(message)
                        raise Exception(message)
                    self.config.model_config.head_configs[self.model_type][key][
                        "classes"
                    ] = classes

    def _setup_ckpt_path(self):
        """Setup checkpoint path."""
        # if run_name is None, assign a new dir name
        ckpt_dir = self.config.trainer_config.ckpt_dir
        if ckpt_dir is None or ckpt_dir == "" or ckpt_dir == "None":
            ckpt_dir = "."
            self.config.trainer_config.ckpt_dir = ckpt_dir
        run_name = self.config.trainer_config.run_name
        if run_name is None or run_name == "" or run_name == "None":
            sum_train_lfs = sum([len(train_label) for train_label in self.train_labels])
            sum_val_lfs = sum([len(val_label) for val_label in self.val_labels])
            run_name = (
                datetime.now().strftime("%y%m%d_%H%M%S")
                + f".{self.model_type}.n={sum_train_lfs + sum_val_lfs}"
            )

        # If checkpoint path already exists, add suffix to prevent overwriting
        if (Path(ckpt_dir) / run_name).exists() and (
            Path(ckpt_dir) / run_name / "best.ckpt"
        ).exists():
            logger.info(
                f"Checkpoint path already exists: {Path(ckpt_dir) / run_name}... adding suffix to prevent overwriting."
            )
            for i in count(1):
                new_run_name = f"{run_name}-{i}"
                if not (Path(ckpt_dir) / new_run_name).exists():
                    run_name = new_run_name
                    break

        self.config.trainer_config.run_name = run_name

        # set output dir for cache img
        if self.config.data_config.data_pipeline_fw == "torch_dataset_cache_img_disk":
            if self.config.data_config.cache_img_path is None:
                self.config.data_config.cache_img_path = (
                    Path(self.config.trainer_config.ckpt_dir)
                    / self.config.trainer_config.run_name
                )

    def _verify_model_input_channels(self):
        """Verify input channels in model_config based on input image and pretrained model weights."""
        # check in channels, verify with img channels / ensure_rgb/ ensure_grayscale
        if self.train_labels[0] is not None:
            img_channels = self.train_labels[0][0].image.shape[-1]
            if self.config.data_config.preprocessing.ensure_rgb:
                img_channels = 3
            if self.config.data_config.preprocessing.ensure_grayscale:
                img_channels = 1
            if (
                self.config.model_config.backbone_config[
                    f"{self.backbone_type}"
                ].in_channels
                != img_channels
            ):
                self.config.model_config.backbone_config[
                    f"{self.backbone_type}"
                ].in_channels = img_channels
                logger.info(
                    f"Updating backbone in_channels to {img_channels} based on the input image channels."
                )

        # verify input img channels with pretrained model ckpts (if any)
        if (
            self.backbone_type == "convnext" or self.backbone_type == "swint"
        ) and self.config.model_config.backbone_config[
            f"{self.backbone_type}"
        ].pre_trained_weights is not None:
            if (
                self.config.model_config.backbone_config[
                    f"{self.backbone_type}"
                ].in_channels
                != 3
            ):
                self.config.model_config.backbone_config[
                    f"{self.backbone_type}"
                ].in_channels = 3
                self.config.data_config.preprocessing.ensure_rgb = True
                self.config.data_config.preprocessing.ensure_grayscale = False
                logger.info(
                    f"Updating backbone in_channels to 3 based on the pretrained model weights."
                )

        elif (
            self.backbone_type == "unet"
            and self.config.model_config.pretrained_backbone_weights is not None
        ):
            if self.config.model_config.pretrained_backbone_weights.endswith(".ckpt"):
                pretrained_backbone_ckpt = torch.load(
                    self.config.model_config.pretrained_backbone_weights,
                    map_location="cpu",  # this will be loaded on cpu as it's just used to get the input channels
                    weights_only=False,
                )
                input_channels = list(pretrained_backbone_ckpt["state_dict"].values())[
                    0
                ].shape[
                    -3
                ]  # get input channels from first layer
                if (
                    self.config.model_config.backbone_config.unet.in_channels
                    != input_channels
                ):
                    self.config.model_config.backbone_config.unet.in_channels = (
                        input_channels
                    )
                    logger.info(
                        f"Updating backbone in_channels to {input_channels} based on the pretrained model weights."
                    )

                    if input_channels == 1:
                        self.config.data_config.preprocessing.ensure_grayscale = True
                        self.config.data_config.preprocessing.ensure_rgb = False
                        logger.info(
                            f"Updating data preprocessing to ensure_grayscale to True based on the pretrained model weights."
                        )
                    elif input_channels == 3:
                        self.config.data_config.preprocessing.ensure_rgb = True
                        self.config.data_config.preprocessing.ensure_grayscale = False
                        logger.info(
                            f"Updating data preprocessing to ensure_rgb to True based on the pretrained model weights."
                        )

            elif self.config.model_config.pretrained_backbone_weights.endswith(".h5"):
                input_channels = get_keras_first_layer_channels(
                    self.config.model_config.pretrained_backbone_weights
                )
                if (
                    self.config.model_config.backbone_config.unet.in_channels
                    != input_channels
                ):
                    self.config.model_config.backbone_config.unet.in_channels = (
                        input_channels
                    )
                    logger.info(
                        f"Updating backbone in_channels to {input_channels} based on the pretrained model weights."
                    )

                    if input_channels == 1:
                        self.config.data_config.preprocessing.ensure_grayscale = True
                        self.config.data_config.preprocessing.ensure_rgb = False
                        logger.info(
                            f"Updating data preprocessing to ensure_grayscale to True based on the pretrained model weights."
                        )
                    elif input_channels == 3:
                        self.config.data_config.preprocessing.ensure_rgb = True
                        self.config.data_config.preprocessing.ensure_grayscale = False
                        logger.info(
                            f"Updating data preprocessing to ensure_rgb to True based on the pretrained model weights."
                        )

    def setup_config(self):
        """Compute config parameters."""
        logger.info("Setting up config...")

        # Normalize empty strings to None for optional wandb fields
        if self.config.trainer_config.wandb.prv_runid == "":
            self.config.trainer_config.wandb.prv_runid = None

        # compute preprocessing parameters from the labels objects and fill in the config
        self._setup_preprocessing_config()

        # save skeleton to config
        skeleton_yaml = yaml.safe_load(SkeletonYAMLEncoder().encode(self.skeletons))
        skeleton_names = skeleton_yaml.keys()
        self.config["data_config"]["skeletons"] = []
        for skeleton_name in skeleton_names:
            skl = skeleton_yaml[skeleton_name]
            skl["name"] = skeleton_name
            self.config["data_config"]["skeletons"].append(skl)

        # setup head config - partnames, edges and class names
        self._setup_head_config()

        # set max stride for the backbone: convnext and swint
        if self.backbone_type == "convnext":
            self.config.model_config.backbone_config.convnext.max_stride = (
                self.config.model_config.backbone_config.convnext.stem_patch_stride
                * (2**3)
                * 2
            )
        elif self.backbone_type == "swint":
            self.config.model_config.backbone_config.swint.max_stride = (
                self.config.model_config.backbone_config.swint.stem_patch_stride
                * (2**3)
                * 2
            )

        # set output stride for backbone from head config and verify max stride
        self.config = check_output_strides(self.config)

        # if trainer_devices is None, set it to "auto"
        if self.config.trainer_config.trainer_devices is None:
            self.config.trainer_config.trainer_devices = (
                "auto"
                if OmegaConf.select(
                    self.config, "trainer_config.trainer_device_indices", default=None
                )
                is None
                else len(
                    OmegaConf.select(
                        self.config,
                        "trainer_config.trainer_device_indices",
                        default=None,
                    )
                )
            )

        # setup checkpoint path (generates run_name if not specified)
        self._setup_ckpt_path()

        # Default wandb run name to trainer run_name if not specified
        # Note: This must come after _setup_ckpt_path() which generates run_name
        if self.config.trainer_config.wandb.name is None:
            self.config.trainer_config.wandb.name = self.config.trainer_config.run_name

        # verify input_channels in model_config based on input image and pretrained model weights
        self._verify_model_input_channels()

    def _setup_model_ckpt_dir(self):
        """Create the model ckpt folder and save ground truth labels."""
        ckpt_path = (
            Path(self.config.trainer_config.ckpt_dir)
            / self.config.trainer_config.run_name
        ).as_posix()
        logger.info(f"Setting up model ckpt dir: `{ckpt_path}`...")

        if not Path(ckpt_path).exists():
            try:
                Path(ckpt_path).mkdir(parents=True, exist_ok=True)
            except OSError as e:
                message = f"Cannot create a new folder in {ckpt_path}.\n {e}"
                logger.error(message)
                raise OSError(message)

        if RANK in [0, -1]:
            # Check if we should filter to user-labeled frames only
            user_instances_only = OmegaConf.select(
                self.config, "data_config.user_instances_only", default=True
            )

            # Save train and val ground truth labels
            for idx, (train, val) in enumerate(zip(self.train_labels, self.val_labels)):
                # Filter to user-labeled frames if needed (for evaluation)
                if user_instances_only:
                    train_filtered = self._filter_to_user_labeled(train)
                    val_filtered = self._filter_to_user_labeled(val)
                else:
                    train_filtered = train
                    val_filtered = val

                train_filtered.save(
                    Path(ckpt_path) / f"labels_gt.train.{idx}.slp",
                    restore_original_videos=False,
                )
                val_filtered.save(
                    Path(ckpt_path) / f"labels_gt.val.{idx}.slp",
                    restore_original_videos=False,
                )

            # Save test ground truth labels if test paths are provided
            test_file_path = OmegaConf.select(
                self.config, "data_config.test_file_path", default=None
            )
            if test_file_path is not None:
                # Normalize to list of strings
                if isinstance(test_file_path, str):
                    test_paths = [test_file_path]
                else:
                    test_paths = list(test_file_path)

                for idx, test_path in enumerate(test_paths):
                    # Only save if it's a .slp file (not a video file)
                    if test_path.endswith(".slp") or test_path.endswith(".pkg.slp"):
                        try:
                            test_labels = sio.load_slp(test_path)
                            if user_instances_only:
                                test_filtered = self._filter_to_user_labeled(
                                    test_labels
                                )
                            else:
                                test_filtered = test_labels
                            test_filtered.save(
                                Path(ckpt_path) / f"labels_gt.test.{idx}.slp",
                                restore_original_videos=False,
                            )
                        except Exception as e:
                            logger.warning(
                                f"Could not save test ground truth for {test_path}: {e}"
                            )

    def _setup_viz_datasets(self):
        """Setup dataloaders."""
        data_viz_config = self.config.copy()
        data_viz_config.data_config.data_pipeline_fw = "torch_dataset"

        return get_train_val_datasets(
            train_labels=self.train_labels,
            val_labels=self.val_labels,
            config=data_viz_config,
            rank=-1,
        )

    def _setup_datasets(self):
        """Setup dataloaders."""
        base_cache_img_path = None
        if self.config.data_config.data_pipeline_fw == "torch_dataset_cache_img_memory":
            # check available memory. If insufficient memory, default to disk caching.
            mem_available = check_cache_memory(
                self.train_labels, self.val_labels, memory_buffer=MEMORY_BUFFER
            )
            if not mem_available:
                self.config.data_config.data_pipeline_fw = (
                    "torch_dataset_cache_img_disk"
                )
                base_cache_img_path = Path("./")
                logger.info(
                    f"Insufficient memory for in-memory caching. `jpg` files will be created for disk-caching."
                )
            self.config.data_config.cache_img_path = base_cache_img_path

        elif self.config.data_config.data_pipeline_fw == "torch_dataset_cache_img_disk":
            # Get cache img path
            base_cache_img_path = (
                Path(self.config.data_config.cache_img_path)
                if self.config.data_config.cache_img_path is not None
                else Path(self.config.trainer_config.ckpt_dir)
                / self.config.trainer_config.run_name
            )

            if self.config.data_config.cache_img_path is None:
                self.config.data_config.cache_img_path = base_cache_img_path

        return get_train_val_datasets(
            train_labels=self.train_labels,
            val_labels=self.val_labels,
            config=self.config,
            rank=self.trainer.global_rank,
        )

    def _setup_loggers_callbacks(self, viz_train_dataset, viz_val_dataset):
        """Create loggers and callbacks."""
        logger.info("Setting up callbacks and loggers...")
        loggers = []
        callbacks = []
        if self.config.trainer_config.save_ckpt:
            # checkpoint callback
            checkpoint_callback = ModelCheckpoint(
                save_top_k=self.config.trainer_config.model_ckpt.save_top_k,
                save_last=self.config.trainer_config.model_ckpt.save_last,
                dirpath=(
                    Path(self.config.trainer_config.ckpt_dir)
                    / self.config.trainer_config.run_name
                ).as_posix(),
                filename="best",
                monitor="val/loss",
                mode="min",
            )
            callbacks.append(checkpoint_callback)

            # csv log callback
            csv_log_keys = [
                "epoch",
                "train/loss",
                "val/loss",
                "learning_rate",
                "train/time",
                "val/time",
            ]
            # Add model-specific keys for wandb parity
            if self.model_type in [
                "single_instance",
                "centered_instance",
                "multi_class_topdown",
            ]:
                csv_log_keys.extend(
                    [f"train/confmaps/{name}" for name in self.skeletons[0].node_names]
                )
            if self.model_type == "bottomup":
                csv_log_keys.extend(
                    [
                        "train/confmaps_loss",
                        "train/paf_loss",
                        "val/confmaps_loss",
                        "val/paf_loss",
                    ]
                )
            if self.model_type == "multi_class_bottomup":
                csv_log_keys.extend(
                    [
                        "train/confmaps_loss",
                        "train/classmap_loss",
                        "train/class_accuracy",
                        "val/confmaps_loss",
                        "val/classmap_loss",
                        "val/class_accuracy",
                    ]
                )
            if self.model_type == "multi_class_topdown":
                csv_log_keys.extend(
                    [
                        "train/confmaps_loss",
                        "train/classvector_loss",
                        "train/class_accuracy",
                        "val/confmaps_loss",
                        "val/classvector_loss",
                        "val/class_accuracy",
                    ]
                )
            csv_logger = CSVLoggerCallback(
                filepath=Path(self.config.trainer_config.ckpt_dir)
                / self.config.trainer_config.run_name
                / "training_log.csv",
                keys=csv_log_keys,
            )
            callbacks.append(csv_logger)

        if self.config.trainer_config.early_stopping.stop_training_on_plateau:
            # early stopping callback
            callbacks.append(
                EarlyStopping(
                    monitor="val/loss",
                    mode="min",
                    verbose=False,
                    min_delta=self.config.trainer_config.early_stopping.min_delta,
                    patience=self.config.trainer_config.early_stopping.patience,
                )
            )

        if self.config.trainer_config.use_wandb:
            # wandb logger
            wandb_config = self.config.trainer_config.wandb
            if wandb_config.wandb_mode == "offline":
                os.environ["WANDB_MODE"] = "offline"
            else:
                if RANK in [0, -1]:
                    wandb.login(key=self.config.trainer_config.wandb.api_key)
            wandb_logger = WandbLogger(
                entity=wandb_config.entity,
                project=wandb_config.project,
                name=wandb_config.name,
                save_dir=(
                    Path(self.config.trainer_config.ckpt_dir)
                    / self.config.trainer_config.run_name
                ).as_posix(),
                id=self.config.trainer_config.wandb.prv_runid,
                group=self.config.trainer_config.wandb.group,
            )
            loggers.append(wandb_logger)

            # Log message about wandb local logs cleanup
            should_delete_wandb_logs = wandb_config.delete_local_logs is True or (
                wandb_config.delete_local_logs is None
                and wandb_config.wandb_mode != "offline"
            )
            if should_delete_wandb_logs:
                logger.info(
                    "WandB local logs will be deleted after training completes. "
                    "To keep logs, set trainer_config.wandb.delete_local_logs=false"
                )

            # save the configs as yaml in the checkpoint dir
            # Mask API key in both configs to prevent saving to disk
            self.config.trainer_config.wandb.api_key = ""
            if self._initial_config is not None:
                self._initial_config.trainer_config.wandb.api_key = ""

        # zmq callbacks
        if self.config.trainer_config.zmq.controller_port is not None:
            controller_address = "tcp://127.0.0.1:" + str(
                self.config.trainer_config.zmq.controller_port
            )
            callbacks.append(TrainingControllerZMQ(address=controller_address))
        if self.config.trainer_config.zmq.publish_port is not None:
            publish_address = "tcp://127.0.0.1:" + str(
                self.config.trainer_config.zmq.publish_port
            )
            callbacks.append(ProgressReporterZMQ(address=publish_address))

        # viz callbacks
        if self.config.trainer_config.visualize_preds_during_training:
            train_viz_pipeline = cycle(viz_train_dataset)
            val_viz_pipeline = cycle(viz_val_dataset)

            viz_dir = (
                Path(self.config.trainer_config.ckpt_dir)
                / self.config.trainer_config.run_name
                / "viz"
            )
            if not Path(viz_dir).exists():
                if RANK in [0, -1]:
                    Path(viz_dir).mkdir(parents=True, exist_ok=True)

            callbacks.append(
                MatplotlibSaver(
                    save_folder=viz_dir,
                    plot_fn=lambda: self.lightning_model.visualize_example(
                        next(train_viz_pipeline)
                    ),
                    prefix="train",
                )
            )
            callbacks.append(
                MatplotlibSaver(
                    save_folder=viz_dir,
                    plot_fn=lambda: self.lightning_model.visualize_example(
                        next(val_viz_pipeline)
                    ),
                    prefix="validation",
                )
            )

            if self.model_type == "bottomup":
                train_viz_pipeline1 = cycle(copy.deepcopy(viz_train_dataset))
                val_viz_pipeline1 = cycle(copy.deepcopy(viz_val_dataset))
                callbacks.append(
                    MatplotlibSaver(
                        save_folder=viz_dir,
                        plot_fn=lambda: self.lightning_model.visualize_pafs_example(
                            next(train_viz_pipeline1)
                        ),
                        prefix="train.pafs_magnitude",
                    )
                )
                callbacks.append(
                    MatplotlibSaver(
                        save_folder=viz_dir,
                        plot_fn=lambda: self.lightning_model.visualize_pafs_example(
                            next(val_viz_pipeline1)
                        ),
                        prefix="validation.pafs_magnitude",
                    )
                )

            if self.model_type == "multi_class_bottomup":
                train_viz_pipeline1 = cycle(copy.deepcopy(viz_train_dataset))
                val_viz_pipeline1 = cycle(copy.deepcopy(viz_val_dataset))
                callbacks.append(
                    MatplotlibSaver(
                        save_folder=viz_dir,
                        plot_fn=lambda: self.lightning_model.visualize_class_maps_example(
                            next(train_viz_pipeline1)
                        ),
                        prefix="train.class_maps",
                    )
                )
                callbacks.append(
                    MatplotlibSaver(
                        save_folder=viz_dir,
                        plot_fn=lambda: self.lightning_model.visualize_class_maps_example(
                            next(val_viz_pipeline1)
                        ),
                        prefix="validation.class_maps",
                    )
                )

            if self.config.trainer_config.use_wandb and OmegaConf.select(
                self.config, "trainer_config.wandb.save_viz_imgs_wandb", default=False
            ):
                # Get wandb viz config options
                viz_enabled = OmegaConf.select(
                    self.config, "trainer_config.wandb.viz_enabled", default=True
                )
                viz_boxes = OmegaConf.select(
                    self.config, "trainer_config.wandb.viz_boxes", default=False
                )
                viz_masks = OmegaConf.select(
                    self.config, "trainer_config.wandb.viz_masks", default=False
                )
                viz_box_size = OmegaConf.select(
                    self.config, "trainer_config.wandb.viz_box_size", default=5.0
                )
                viz_confmap_threshold = OmegaConf.select(
                    self.config,
                    "trainer_config.wandb.viz_confmap_threshold",
                    default=0.1,
                )
                log_viz_table = OmegaConf.select(
                    self.config, "trainer_config.wandb.log_viz_table", default=False
                )

                # Create viz data pipelines for wandb callback
                wandb_train_viz_pipeline = cycle(copy.deepcopy(viz_train_dataset))
                wandb_val_viz_pipeline = cycle(copy.deepcopy(viz_val_dataset))

                if self.model_type == "bottomup":
                    # Bottom-up model needs PAF visualizations
                    wandb_train_pafs_pipeline = cycle(copy.deepcopy(viz_train_dataset))
                    wandb_val_pafs_pipeline = cycle(copy.deepcopy(viz_val_dataset))
                    callbacks.append(
                        WandBVizCallbackWithPAFs(
                            train_viz_fn=lambda: self.lightning_model.get_visualization_data(
                                next(wandb_train_viz_pipeline)
                            ),
                            val_viz_fn=lambda: self.lightning_model.get_visualization_data(
                                next(wandb_val_viz_pipeline)
                            ),
                            train_pafs_viz_fn=lambda: self.lightning_model.get_visualization_data(
                                next(wandb_train_pafs_pipeline), include_pafs=True
                            ),
                            val_pafs_viz_fn=lambda: self.lightning_model.get_visualization_data(
                                next(wandb_val_pafs_pipeline), include_pafs=True
                            ),
                            viz_enabled=viz_enabled,
                            viz_boxes=viz_boxes,
                            viz_masks=viz_masks,
                            box_size=viz_box_size,
                            confmap_threshold=viz_confmap_threshold,
                            log_table=log_viz_table,
                        )
                    )
                else:
                    # Standard models
                    callbacks.append(
                        WandBVizCallback(
                            train_viz_fn=lambda: self.lightning_model.get_visualization_data(
                                next(wandb_train_viz_pipeline)
                            ),
                            val_viz_fn=lambda: self.lightning_model.get_visualization_data(
                                next(wandb_val_viz_pipeline)
                            ),
                            viz_enabled=viz_enabled,
                            viz_boxes=viz_boxes,
                            viz_masks=viz_masks,
                            box_size=viz_box_size,
                            confmap_threshold=viz_confmap_threshold,
                            log_table=log_viz_table,
                        )
                    )

        # Add custom progress bar with better metric formatting
        if self.config.trainer_config.enable_progress_bar:
            callbacks.append(SleapProgressBar())

        # Add epoch-end evaluation callback if enabled
        if self.config.trainer_config.eval.enabled:
            callbacks.append(
                EpochEndEvaluationCallback(
                    skeleton=self.skeletons[0],
                    videos=self.val_labels[0].videos,
                    eval_frequency=self.config.trainer_config.eval.frequency,
                    oks_stddev=self.config.trainer_config.eval.oks_stddev,
                    oks_scale=self.config.trainer_config.eval.oks_scale,
                )
            )

        return loggers, callbacks

    def _delete_cache_imgs(self):
        """Delete cache images in disk."""
        base_cache_img_path = Path(self.config.data_config.cache_img_path)
        train_cache_img_path = Path(base_cache_img_path) / "train_imgs"
        val_cache_img_path = Path(base_cache_img_path) / "val_imgs"

        if (train_cache_img_path).exists():
            logger.info(f"Deleting cache imgs from `{train_cache_img_path}`...")
            shutil.rmtree(
                (train_cache_img_path).as_posix(),
                ignore_errors=True,
            )

        if (val_cache_img_path).exists():
            logger.info(f"Deleting cache imgs from `{val_cache_img_path}`...")
            shutil.rmtree(
                (val_cache_img_path).as_posix(),
                ignore_errors=True,
            )

    def train(self):
        """Train the lightning model."""
        logger.info(f"Setting up for training...")
        start_setup_time = time.time()

        # initialize the labels object and update config.
        if not len(self.train_labels) or not len(self.val_labels):
            self._setup_train_val_labels(self.config)
            self.setup_config()

        # create the ckpt dir.
        self._setup_model_ckpt_dir()

        # create the train and val datasets for visualization.
        viz_train_dataset = None
        viz_val_dataset = None
        if self.config.trainer_config.visualize_preds_during_training:
            logger.info(f"Setting up visualization train and val datasets...")
            viz_train_dataset, viz_val_dataset = self._setup_viz_datasets()

        # setup loggers and callbacks for Trainer.
        logger.info(f"Setting up Trainer...")
        loggers, callbacks = self._setup_loggers_callbacks(
            viz_train_dataset=viz_train_dataset, viz_val_dataset=viz_val_dataset
        )
        # set up the strategy (for multi-gpu training)
        strategy = OmegaConf.select(
            self.config, "trainer_config.trainer_strategy", default="auto"
        )
        # set up profilers
        cfg_profiler = self.config.trainer_config.profiler
        profiler = None
        if cfg_profiler is not None:
            if cfg_profiler in self._profilers:
                profiler = self._profilers[cfg_profiler]
            else:
                message = f"{cfg_profiler} is not a valid option. Please choose one of {list(self._profilers.keys())}"
                logger.error(message)
                raise ValueError(message)

        devices = (
            OmegaConf.select(
                self.config, "trainer_config.trainer_device_indices", default=None
            )
            if OmegaConf.select(
                self.config, "trainer_config.trainer_device_indices", default=None
            )
            is not None
            else self.config.trainer_config.trainer_devices
        )
        logger.info(f"Trainer devices: {devices}")

        # if trainer devices is set to less than the number of available GPUs, use the least used GPUs
        if (
            torch.cuda.is_available()
            and self.config.trainer_config.trainer_accelerator != "cpu"
            and isinstance(self.config.trainer_config.trainer_devices, int)
            and self.config.trainer_config.trainer_devices < torch.cuda.device_count()
            and self.config.trainer_config.trainer_device_indices is None
        ):
            devices = [
                int(x)
                for x in np.argsort(get_gpu_memory())[::-1][
                    : self.config.trainer_config.trainer_devices
                ]
            ]
            logger.info(f"Using GPUs with most available memory: {devices}")

        # create lightning.Trainer instance.
        self.trainer = L.Trainer(
            callbacks=callbacks,
            logger=loggers,
            enable_checkpointing=self.config.trainer_config.save_ckpt,
            devices=devices,
            max_epochs=self.config.trainer_config.max_epochs,
            accelerator=self.config.trainer_config.trainer_accelerator,
            enable_progress_bar=self.config.trainer_config.enable_progress_bar,
            strategy=strategy,
            profiler=profiler,
            log_every_n_steps=1,
        )

        self.trainer.strategy.barrier()

        # setup datasets
        train_dataset, val_dataset = self._setup_datasets()

        # set-up steps per epoch
        train_steps_per_epoch = self.config.trainer_config.train_steps_per_epoch
        if train_steps_per_epoch is None:
            train_steps_per_epoch = get_steps_per_epoch(
                dataset=train_dataset,
                batch_size=self.config.trainer_config.train_data_loader.batch_size,
            )
        if self.config.trainer_config.min_train_steps_per_epoch > train_steps_per_epoch:
            train_steps_per_epoch = self.config.trainer_config.min_train_steps_per_epoch
        self.config.trainer_config.train_steps_per_epoch = train_steps_per_epoch

        val_steps_per_epoch = get_steps_per_epoch(
            dataset=val_dataset,
            batch_size=self.config.trainer_config.val_data_loader.batch_size,
        )

        logger.info(f"Training on {self.trainer.num_devices} device(s)")
        logger.info(f"Training on {self.trainer.strategy.root_device} accelerator")

        # initialize the lightning model.
        # need to initialize after Trainer is initialized (for trainer accelerator)
        logger.info(f"Setting up lightning module for {self.model_type} model...")
        self.lightning_model = LightningModel.get_lightning_model_from_config(
            config=self.config,
        )
        logger.info(f"Backbone model: {self.lightning_model.model.backbone}")
        logger.info(f"Head model: {self.lightning_model.model.head_layers}")
        total_params = sum(p.numel() for p in self.lightning_model.parameters())
        logger.info(f"Total model parameters: {total_params:,}")
        self.config.model_config.total_params = total_params

        # setup dataloaders
        # need to set up dataloaders after Trainer is initialized (for ddp). DistributedSampler depends on the rank
        logger.info(
            f"Input image shape: {train_dataset[0]['image'].shape if 'image' in train_dataset[0] else train_dataset[0]['instance_image'].shape}"
        )
        train_dataloader, val_dataloader = get_train_val_dataloaders(
            train_dataset=train_dataset,
            val_dataset=val_dataset,
            config=self.config,
            rank=self.trainer.global_rank,
            train_steps_per_epoch=self.config.trainer_config.train_steps_per_epoch,
            val_steps_per_epoch=val_steps_per_epoch,
            trainer_devices=self.trainer.num_devices,
        )

        if self.trainer.global_rank == 0:  # save config only in rank 0 process
            ckpt_path = (
                Path(self.config.trainer_config.ckpt_dir)
                / self.config.trainer_config.run_name
            ).as_posix()
            OmegaConf.save(
                self._initial_config,
                (Path(ckpt_path) / "initial_config.yaml").as_posix(),
            )

            if self.config.trainer_config.use_wandb:
                if wandb.run is None:
                    wandb.init(
                        dir=(
                            Path(self.config.trainer_config.ckpt_dir)
                            / self.config.trainer_config.run_name
                        ).as_posix(),
                        project=self.config.trainer_config.wandb.project,
                        entity=self.config.trainer_config.wandb.entity,
                        name=self.config.trainer_config.wandb.name,
                        id=self.config.trainer_config.wandb.prv_runid,
                        group=self.config.trainer_config.wandb.group,
                    )

                # Define custom x-axes for wandb metrics
                # Epoch-level metrics use epoch as x-axis, step-level use default global_step
                wandb.define_metric("epoch")

                # Training metrics (train/ prefix for grouping) - all use epoch x-axis
                wandb.define_metric("train/*", step_metric="epoch")
                wandb.define_metric("train/confmaps/*", step_metric="epoch")

                # Validation metrics (val/ prefix for grouping)
                wandb.define_metric("val/*", step_metric="epoch")

                # Evaluation metrics (eval/ prefix for grouping)
                wandb.define_metric("eval/*", step_metric="epoch")

                # Visualization images (need explicit nested paths)
                wandb.define_metric("viz/*", step_metric="epoch")
                wandb.define_metric("viz/train/*", step_metric="epoch")
                wandb.define_metric("viz/val/*", step_metric="epoch")

                self.config.trainer_config.wandb.current_run_id = wandb.run.id
                wandb.config["run_name"] = self.config.trainer_config.wandb.name
                wandb.config["run_config"] = OmegaConf.to_container(
                    self.config, resolve=True
                )

            OmegaConf.save(
                self.config,
                (
                    Path(self.config.trainer_config.ckpt_dir)
                    / self.config.trainer_config.run_name
                    / "training_config.yaml"
                ).as_posix(),
            )

        self.trainer.strategy.barrier()

        # Flag to track if training was interrupted (not completed normally)
        training_interrupted = False

        try:
            logger.info(
                f"Finished trainer set up. [{time.time() - start_setup_time:.1f}s]"
            )
            logger.info(f"Starting training loop...")
            start_train_time = time.time()
            self.trainer.fit(
                self.lightning_model,
                train_dataloader,
                val_dataloader,
                ckpt_path=self.config.trainer_config.resume_ckpt_path,
            )

        except KeyboardInterrupt:
            logger.info("Stopping training...")
            training_interrupted = True

        finally:
            logger.info(
                f"Finished training loop. [{(time.time() - start_train_time) / 60:.1f} min]"
            )
            # Note: wandb.finish() is called in train.py after post-training evaluation

            # delete image disk caching
            if (
                self.config.data_config.data_pipeline_fw
                == "torch_dataset_cache_img_disk"
                and self.config.data_config.delete_cache_imgs_after_training
            ):
                if self.trainer.global_rank == 0:
                    self._delete_cache_imgs()

            # delete viz folder if requested
            if (
                self.config.trainer_config.visualize_preds_during_training
                and not self.config.trainer_config.keep_viz
            ):
                if self.trainer.global_rank == 0:
                    viz_dir = (
                        Path(self.config.trainer_config.ckpt_dir)
                        / self.config.trainer_config.run_name
                        / "viz"
                    )
                    if viz_dir.exists():
                        logger.info(f"Deleting viz folder at {viz_dir}...")
                        shutil.rmtree(viz_dir, ignore_errors=True)

            # Clean up entire run folder if training was interrupted (KeyboardInterrupt)
            if training_interrupted and self.trainer.global_rank == 0:
                run_dir = (
                    Path(self.config.trainer_config.ckpt_dir)
                    / self.config.trainer_config.run_name
                )
                if run_dir.exists():
                    logger.info(
                        f"Training canceled - cleaning up run folder at {run_dir}..."
                    )
                    shutil.rmtree(run_dir, ignore_errors=True)

get_model_trainer_from_config(config, train_labels=None, val_labels=None) classmethod

Create a model trainer instance from config.

Source code in sleap_nn/training/model_trainer.py
@classmethod
def get_model_trainer_from_config(
    cls,
    config: DictConfig,
    train_labels: Optional[List[sio.Labels]] = None,
    val_labels: Optional[List[sio.Labels]] = None,
):
    """Create a model trainer instance from config."""
    # Verify config structure.
    config = verify_training_cfg(config)

    model_trainer = cls(config=config)

    model_trainer.model_type = get_model_type_from_cfg(model_trainer.config)
    model_trainer.backbone_type = get_backbone_type_from_cfg(model_trainer.config)

    if model_trainer.config.trainer_config.seed is not None:
        model_trainer._set_seed()

    if train_labels is None and val_labels is None:
        # read labels from paths provided in the config
        train_labels = [
            sio.load_slp(path)
            for path in model_trainer.config.data_config.train_labels_path
        ]
        val_labels = (
            [
                sio.load_slp(path)
                for path in model_trainer.config.data_config.val_labels_path
            ]
            if model_trainer.config.data_config.val_labels_path is not None
            else None
        )
        model_trainer._setup_train_val_labels(
            labels=train_labels, val_labels=val_labels
        )
    else:
        model_trainer._setup_train_val_labels(
            labels=train_labels, val_labels=val_labels
        )

    model_trainer._initial_config = model_trainer.config.copy()
    # update config parameters
    model_trainer.setup_config()

    # Check if all videos exist across all labels
    all_videos_exist = all(
        video.exists(check_all=True)
        for labels in [*model_trainer.train_labels, *model_trainer.val_labels]
        for video in labels.videos
    )

    if not all_videos_exist:
        raise FileNotFoundError(
            "One or more video files do not exist or are not accessible."
        )

    return model_trainer

setup_config()

Compute config parameters.

Source code in sleap_nn/training/model_trainer.py
def setup_config(self):
    """Compute config parameters."""
    logger.info("Setting up config...")

    # Normalize empty strings to None for optional wandb fields
    if self.config.trainer_config.wandb.prv_runid == "":
        self.config.trainer_config.wandb.prv_runid = None

    # compute preprocessing parameters from the labels objects and fill in the config
    self._setup_preprocessing_config()

    # save skeleton to config
    skeleton_yaml = yaml.safe_load(SkeletonYAMLEncoder().encode(self.skeletons))
    skeleton_names = skeleton_yaml.keys()
    self.config["data_config"]["skeletons"] = []
    for skeleton_name in skeleton_names:
        skl = skeleton_yaml[skeleton_name]
        skl["name"] = skeleton_name
        self.config["data_config"]["skeletons"].append(skl)

    # setup head config - partnames, edges and class names
    self._setup_head_config()

    # set max stride for the backbone: convnext and swint
    if self.backbone_type == "convnext":
        self.config.model_config.backbone_config.convnext.max_stride = (
            self.config.model_config.backbone_config.convnext.stem_patch_stride
            * (2**3)
            * 2
        )
    elif self.backbone_type == "swint":
        self.config.model_config.backbone_config.swint.max_stride = (
            self.config.model_config.backbone_config.swint.stem_patch_stride
            * (2**3)
            * 2
        )

    # set output stride for backbone from head config and verify max stride
    self.config = check_output_strides(self.config)

    # if trainer_devices is None, set it to "auto"
    if self.config.trainer_config.trainer_devices is None:
        self.config.trainer_config.trainer_devices = (
            "auto"
            if OmegaConf.select(
                self.config, "trainer_config.trainer_device_indices", default=None
            )
            is None
            else len(
                OmegaConf.select(
                    self.config,
                    "trainer_config.trainer_device_indices",
                    default=None,
                )
            )
        )

    # setup checkpoint path (generates run_name if not specified)
    self._setup_ckpt_path()

    # Default wandb run name to trainer run_name if not specified
    # Note: This must come after _setup_ckpt_path() which generates run_name
    if self.config.trainer_config.wandb.name is None:
        self.config.trainer_config.wandb.name = self.config.trainer_config.run_name

    # verify input_channels in model_config based on input image and pretrained model weights
    self._verify_model_input_channels()

train()

Train the lightning model.

Source code in sleap_nn/training/model_trainer.py
def train(self):
    """Train the lightning model."""
    logger.info(f"Setting up for training...")
    start_setup_time = time.time()

    # initialize the labels object and update config.
    if not len(self.train_labels) or not len(self.val_labels):
        self._setup_train_val_labels(self.config)
        self.setup_config()

    # create the ckpt dir.
    self._setup_model_ckpt_dir()

    # create the train and val datasets for visualization.
    viz_train_dataset = None
    viz_val_dataset = None
    if self.config.trainer_config.visualize_preds_during_training:
        logger.info(f"Setting up visualization train and val datasets...")
        viz_train_dataset, viz_val_dataset = self._setup_viz_datasets()

    # setup loggers and callbacks for Trainer.
    logger.info(f"Setting up Trainer...")
    loggers, callbacks = self._setup_loggers_callbacks(
        viz_train_dataset=viz_train_dataset, viz_val_dataset=viz_val_dataset
    )
    # set up the strategy (for multi-gpu training)
    strategy = OmegaConf.select(
        self.config, "trainer_config.trainer_strategy", default="auto"
    )
    # set up profilers
    cfg_profiler = self.config.trainer_config.profiler
    profiler = None
    if cfg_profiler is not None:
        if cfg_profiler in self._profilers:
            profiler = self._profilers[cfg_profiler]
        else:
            message = f"{cfg_profiler} is not a valid option. Please choose one of {list(self._profilers.keys())}"
            logger.error(message)
            raise ValueError(message)

    devices = (
        OmegaConf.select(
            self.config, "trainer_config.trainer_device_indices", default=None
        )
        if OmegaConf.select(
            self.config, "trainer_config.trainer_device_indices", default=None
        )
        is not None
        else self.config.trainer_config.trainer_devices
    )
    logger.info(f"Trainer devices: {devices}")

    # if trainer devices is set to less than the number of available GPUs, use the least used GPUs
    if (
        torch.cuda.is_available()
        and self.config.trainer_config.trainer_accelerator != "cpu"
        and isinstance(self.config.trainer_config.trainer_devices, int)
        and self.config.trainer_config.trainer_devices < torch.cuda.device_count()
        and self.config.trainer_config.trainer_device_indices is None
    ):
        devices = [
            int(x)
            for x in np.argsort(get_gpu_memory())[::-1][
                : self.config.trainer_config.trainer_devices
            ]
        ]
        logger.info(f"Using GPUs with most available memory: {devices}")

    # create lightning.Trainer instance.
    self.trainer = L.Trainer(
        callbacks=callbacks,
        logger=loggers,
        enable_checkpointing=self.config.trainer_config.save_ckpt,
        devices=devices,
        max_epochs=self.config.trainer_config.max_epochs,
        accelerator=self.config.trainer_config.trainer_accelerator,
        enable_progress_bar=self.config.trainer_config.enable_progress_bar,
        strategy=strategy,
        profiler=profiler,
        log_every_n_steps=1,
    )

    self.trainer.strategy.barrier()

    # setup datasets
    train_dataset, val_dataset = self._setup_datasets()

    # set-up steps per epoch
    train_steps_per_epoch = self.config.trainer_config.train_steps_per_epoch
    if train_steps_per_epoch is None:
        train_steps_per_epoch = get_steps_per_epoch(
            dataset=train_dataset,
            batch_size=self.config.trainer_config.train_data_loader.batch_size,
        )
    if self.config.trainer_config.min_train_steps_per_epoch > train_steps_per_epoch:
        train_steps_per_epoch = self.config.trainer_config.min_train_steps_per_epoch
    self.config.trainer_config.train_steps_per_epoch = train_steps_per_epoch

    val_steps_per_epoch = get_steps_per_epoch(
        dataset=val_dataset,
        batch_size=self.config.trainer_config.val_data_loader.batch_size,
    )

    logger.info(f"Training on {self.trainer.num_devices} device(s)")
    logger.info(f"Training on {self.trainer.strategy.root_device} accelerator")

    # initialize the lightning model.
    # need to initialize after Trainer is initialized (for trainer accelerator)
    logger.info(f"Setting up lightning module for {self.model_type} model...")
    self.lightning_model = LightningModel.get_lightning_model_from_config(
        config=self.config,
    )
    logger.info(f"Backbone model: {self.lightning_model.model.backbone}")
    logger.info(f"Head model: {self.lightning_model.model.head_layers}")
    total_params = sum(p.numel() for p in self.lightning_model.parameters())
    logger.info(f"Total model parameters: {total_params:,}")
    self.config.model_config.total_params = total_params

    # setup dataloaders
    # need to set up dataloaders after Trainer is initialized (for ddp). DistributedSampler depends on the rank
    logger.info(
        f"Input image shape: {train_dataset[0]['image'].shape if 'image' in train_dataset[0] else train_dataset[0]['instance_image'].shape}"
    )
    train_dataloader, val_dataloader = get_train_val_dataloaders(
        train_dataset=train_dataset,
        val_dataset=val_dataset,
        config=self.config,
        rank=self.trainer.global_rank,
        train_steps_per_epoch=self.config.trainer_config.train_steps_per_epoch,
        val_steps_per_epoch=val_steps_per_epoch,
        trainer_devices=self.trainer.num_devices,
    )

    if self.trainer.global_rank == 0:  # save config only in rank 0 process
        ckpt_path = (
            Path(self.config.trainer_config.ckpt_dir)
            / self.config.trainer_config.run_name
        ).as_posix()
        OmegaConf.save(
            self._initial_config,
            (Path(ckpt_path) / "initial_config.yaml").as_posix(),
        )

        if self.config.trainer_config.use_wandb:
            if wandb.run is None:
                wandb.init(
                    dir=(
                        Path(self.config.trainer_config.ckpt_dir)
                        / self.config.trainer_config.run_name
                    ).as_posix(),
                    project=self.config.trainer_config.wandb.project,
                    entity=self.config.trainer_config.wandb.entity,
                    name=self.config.trainer_config.wandb.name,
                    id=self.config.trainer_config.wandb.prv_runid,
                    group=self.config.trainer_config.wandb.group,
                )

            # Define custom x-axes for wandb metrics
            # Epoch-level metrics use epoch as x-axis, step-level use default global_step
            wandb.define_metric("epoch")

            # Training metrics (train/ prefix for grouping) - all use epoch x-axis
            wandb.define_metric("train/*", step_metric="epoch")
            wandb.define_metric("train/confmaps/*", step_metric="epoch")

            # Validation metrics (val/ prefix for grouping)
            wandb.define_metric("val/*", step_metric="epoch")

            # Evaluation metrics (eval/ prefix for grouping)
            wandb.define_metric("eval/*", step_metric="epoch")

            # Visualization images (need explicit nested paths)
            wandb.define_metric("viz/*", step_metric="epoch")
            wandb.define_metric("viz/train/*", step_metric="epoch")
            wandb.define_metric("viz/val/*", step_metric="epoch")

            self.config.trainer_config.wandb.current_run_id = wandb.run.id
            wandb.config["run_name"] = self.config.trainer_config.wandb.name
            wandb.config["run_config"] = OmegaConf.to_container(
                self.config, resolve=True
            )

        OmegaConf.save(
            self.config,
            (
                Path(self.config.trainer_config.ckpt_dir)
                / self.config.trainer_config.run_name
                / "training_config.yaml"
            ).as_posix(),
        )

    self.trainer.strategy.barrier()

    # Flag to track if training was interrupted (not completed normally)
    training_interrupted = False

    try:
        logger.info(
            f"Finished trainer set up. [{time.time() - start_setup_time:.1f}s]"
        )
        logger.info(f"Starting training loop...")
        start_train_time = time.time()
        self.trainer.fit(
            self.lightning_model,
            train_dataloader,
            val_dataloader,
            ckpt_path=self.config.trainer_config.resume_ckpt_path,
        )

    except KeyboardInterrupt:
        logger.info("Stopping training...")
        training_interrupted = True

    finally:
        logger.info(
            f"Finished training loop. [{(time.time() - start_train_time) / 60:.1f} min]"
        )
        # Note: wandb.finish() is called in train.py after post-training evaluation

        # delete image disk caching
        if (
            self.config.data_config.data_pipeline_fw
            == "torch_dataset_cache_img_disk"
            and self.config.data_config.delete_cache_imgs_after_training
        ):
            if self.trainer.global_rank == 0:
                self._delete_cache_imgs()

        # delete viz folder if requested
        if (
            self.config.trainer_config.visualize_preds_during_training
            and not self.config.trainer_config.keep_viz
        ):
            if self.trainer.global_rank == 0:
                viz_dir = (
                    Path(self.config.trainer_config.ckpt_dir)
                    / self.config.trainer_config.run_name
                    / "viz"
                )
                if viz_dir.exists():
                    logger.info(f"Deleting viz folder at {viz_dir}...")
                    shutil.rmtree(viz_dir, ignore_errors=True)

        # Clean up entire run folder if training was interrupted (KeyboardInterrupt)
        if training_interrupted and self.trainer.global_rank == 0:
            run_dir = (
                Path(self.config.trainer_config.ckpt_dir)
                / self.config.trainer_config.run_name
            )
            if run_dir.exists():
                logger.info(
                    f"Training canceled - cleaning up run folder at {run_dir}..."
                )
                shutil.rmtree(run_dir, ignore_errors=True)