Replace fp16 with amp support for validate.py script

validate.py

@@ -18,6 +18,12 @@ import torch.nn as nn
 import torch.nn.parallel
 from collections import OrderedDict
 
+try:
+    from apex import amp
+    has_apex = True
+except ImportError:
+    has_apex = False
+
 from timm.models import create_model, apply_test_time_pool, load_checkpoint, is_model, list_models
 from timm.data import Dataset, DatasetTar, create_loader, resolve_data_config
 from timm.utils import accuracy, AverageMeter, natural_key, setup_default_logging
@@ -61,8 +67,8 @@ parser.add_argument('--no-prefetcher', action='store_true', default=False,
                     help='disable fast prefetcher')
 parser.add_argument('--pin-mem', action='store_true', default=False,
                     help='Pin CPU memory in DataLoader for more efficient (sometimes) transfer to GPU.')
-parser.add_argument('--fp16', action='store_true', default=False,
+parser.add_argument('--amp', action='store_true', default=False,
-                    help='Use half precision (fp16)')
+                    help='Use AMP mixed precision')
 parser.add_argument('--tf-preprocessing', action='store_true', default=False,
                     help='Use Tensorflow preprocessing pipeline (require CPU TF installed')
 parser.add_argument('--use-ema', dest='use_ema', action='store_true',
@@ -98,13 +104,13 @@ def validate(args):
         torch.jit.optimized_execution(True)
         model = torch.jit.script(model)
 
-    if args.num_gpu > 1:
+    if args.amp:
-        model = torch.nn.DataParallel(model, device_ids=list(range(args.num_gpu))).cuda()
+        model = amp.initialize(model.cuda(), opt_level='O1')
     else:
         model = model.cuda()
 
-    if args.fp16:
+    if args.num_gpu > 1:
-        model = model.half()
+        model = torch.nn.DataParallel(model, device_ids=list(range(args.num_gpu)))
 
     criterion = nn.CrossEntropyLoss().cuda()
 
@@ -127,7 +133,6 @@ def validate(args):
         num_workers=args.workers,
         crop_pct=crop_pct,
         pin_memory=args.pin_mem,
-        fp16=args.fp16,
         tf_preprocessing=args.tf_preprocessing)
 
     batch_time = AverageMeter()