update ppyolotiny tutorial training configuration

dygraph/tutorials/train/object_detection/ppyolotiny.py

@@ -8,7 +8,7 @@ pdx.utils.download_and_decompress(dataset, path='./')
 # 定义训练和验证时的transforms
 # API说明：https://github.com/PaddlePaddle/PaddleX/blob/release/2.0-rc/paddlex/cv/transforms/operators.py
 train_transforms = T.Compose([
-    T.MixupImage(mixup_epoch=250), T.RandomDistort(),
+    T.MixupImage(mixup_epoch=-1), T.RandomDistort(),
     T.RandomExpand(im_padding_value=[123.675, 116.28, 103.53]), T.RandomCrop(),
     T.RandomHorizontalFlip(), T.BatchRandomResize(
         target_sizes=[192, 224, 256, 288, 320, 352, 384, 416, 448, 480, 512],
@@ -46,14 +46,15 @@ model = pdx.models.PPYOLOTiny(num_classes=num_classes)
 # API说明：https://github.com/PaddlePaddle/PaddleX/blob/release/2.0-rc/paddlex/cv/models/detector.py#L155
 # 各参数介绍与调整说明：https://paddlex.readthedocs.io/zh_CN/develop/appendix/parameters.html
 model.train(
-    num_epochs=650,
+    num_epochs=550,
     train_dataset=train_dataset,
     train_batch_size=16,
     eval_dataset=eval_dataset,
-    learning_rate=0.005 / 16,
+    learning_rate=0.005,
     warmup_steps=1000,
     warmup_start_lr=0.0,
-    lr_decay_epochs=[430, 540, 610],
+    lr_decay_epochs=[130, 540],
+    lr_decay_gamma=.5,
     save_interval_epochs=5,
     save_dir='output/ppyolotiny',
     use_vdl=True)