update expt name comment and folder parsing for training (#978)

* comment

* fix parsing

* fix evolve

* folder

* tqdm

* Update train.py

* Update train.py

* reinstate anchors into meta dict

anchor evolution is working correctly now

* reinstate logger

prefer the single line readout for concise logging, which helps simplify notebook and tutorials etc.

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

train.py

     results = (0, 0, 0, 0, 0, 0, 0)  # P, R, mAP@.5, mAP@.5-.95, val_loss(box, obj, cls)
     scheduler.last_epoch = start_epoch - 1  # do not move
     scaler = amp.GradScaler(enabled=cuda)
-    logger.info('Image sizes %g train, %g test\nUsing %g dataloader workers\nLogging results to %s\n'
+    logger.info('Image sizes %g train, %g test\n'
+                'Using %g dataloader workers\nLogging results to %s\n'
                 'Starting training for %g epochs...' % (imgsz, imgsz_test, dataloader.num_workers, log_dir, epochs))
     for epoch in range(start_epoch, epochs):  # epoch ------------------------------------------------------------------
         model.train()
     parser.add_argument('--bucket', type=str, default='', help='gsutil bucket')
     parser.add_argument('--cache-images', action='store_true', help='cache images for faster training')
     parser.add_argument('--image-weights', action='store_true', help='use weighted image selection for training')
-    parser.add_argument('--name', default='', help='renames results.txt to results_name.txt if supplied')
+    parser.add_argument('--name', default='', help='renames experiment folder exp{N} to exp{N}_{name} if supplied')
     parser.add_argument('--device', default='', help='cuda device, i.e. 0 or 0,1,2,3 or cpu')
     parser.add_argument('--multi-scale', action='store_true', help='vary img-size +/- 50%%')
     parser.add_argument('--single-cls', action='store_true', help='train as single-class dataset')
     if not opt.evolve:
         tb_writer = None
         if opt.global_rank in [-1, 0]:
-            logger.info('Start Tensorboard with "tensorboard --logdir %s", view at http://localhost:6006/' % opt.logdir)
+            logger.info(f'Start Tensorboard with "tensorboard --logdir {opt.logdir}", view at http://localhost:6006/')
             tb_writer = SummaryWriter(log_dir=log_dir)  # runs/exp0
 
         train(hyp, opt, device, tb_writer)
         assert opt.local_rank == -1, 'DDP mode not implemented for --evolve'
         opt.notest, opt.nosave = True, True  # only test/save final epoch
         # ei = [isinstance(x, (int, float)) for x in hyp.values()]  # evolvable indices
-        yaml_file = Path('runs/evolve/hyp_evolved.yaml')  # save best result here
+        yaml_file = Path(opt.logdir) / 'evolve' / 'hyp_evolved.yaml'  # save best result here
         if opt.bucket:
             os.system('gsutil cp gs://%s/evolve.txt .' % opt.bucket)  # download evolve.txt if exists
 
 
         # Plot results
         plot_evolution(yaml_file)
-        print('Hyperparameter evolution complete. Best results saved as: %s\nCommand to train a new model with these '
-              'hyperparameters: $ python train.py --hyp %s' % (yaml_file, yaml_file))
+        print(f'Hyperparameter evolution complete. Best results saved as: {yaml_file}\n'
+              f'Command to train a new model with these hyperparameters: $ python train.py --hyp {yaml_file}')

utils/general.py

 import shutil
 import subprocess
 import time
+import re
 from contextlib import contextmanager
 from copy import copy
 from pathlib import Path
     # Increments a directory runs/exp1 --> runs/exp2_comment
     n = 0  # number
     dir = str(Path(dir))  # os-agnostic
-    d = sorted(glob.glob(dir + '*'))  # directories
-    if len(d):
-        n = max([int(x[len(dir):x.rfind('_') if '_' in Path(x).name else None]) for x in d]) + 1  # increment
+    dirs = sorted(glob.glob(dir + '*'))  # directories
+    if dirs:
+        matches = [re.search(r"exp(\d+)", d) for d in dirs]
+        idxs = [int(m.groups()[0]) for m in matches if m]
+        if idxs:
+            n = max(idxs) + 1  # increment
     return dir + str(n) + ('_' + comment if comment else '')