Merge pull request #223 from littletomatodonkey/fix_single_card_dyg

fix single card dygraph train process

tools/program.py

@@ -329,9 +329,13 @@ def run(dataloader, config, net, optimizer=None, epoch=0, mode='train'):
         feeds = create_feeds(batch, use_mix)
         fetchs = create_fetchs(feeds, net, config, mode)
         if mode == 'train':
+            if config["use_data_parallel"]:
                 avg_loss = net.scale_loss(fetchs['loss'])
                 avg_loss.backward()
                 net.apply_collective_grads()
+            else:
+                avg_loss = fetchs['loss']
+                avg_loss.backward()
 
             optimizer.minimize(avg_loss)
             net.clear_gradients()

tools/train.py

@@ -52,9 +52,13 @@ def main(args):
     gpu_id = fluid.dygraph.parallel.Env().dev_id
     place = fluid.CUDAPlace(gpu_id)
 
+    use_data_parallel = int(os.getenv("PADDLE_TRAINERS_NUM", 1)) != 1
+    config["use_data_parallel"] = use_data_parallel
+
     with fluid.dygraph.guard(place):
-        strategy = fluid.dygraph.parallel.prepare_context()
         net = program.create_model(config.ARCHITECTURE, config.classes_num)
+        if config["use_data_parallel"]:
+            strategy = fluid.dygraph.parallel.prepare_context()
             net = fluid.dygraph.parallel.DataParallel(net, strategy)
 
         optimizer = program.create_optimizer(
@@ -79,7 +83,8 @@ def main(args):
             program.run(train_dataloader, config, net, optimizer, epoch_id,
                         'train')
 
-            if fluid.dygraph.parallel.Env().local_rank == 0:
+            if not config["use_data_parallel"] or fluid.dygraph.parallel.Env(
+            ).local_rank == 0:
                 # 2. validate with validate dataset
                 if config.validate and epoch_id % config.valid_interval == 0:
                     net.eval()