Update DetectMultiBackend for tuple outputs 2 (#9275)

* Update DetectMultiBackend for tuple outputs 2

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Update

* Update

* Update

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

models/common.py

@@ -457,7 +457,7 @@ class DetectMultiBackend(nn.Module):
 
         self.__dict__.update(locals())  # assign all variables to self
 
-    def forward(self, im, augment=False, visualize=False, val=False):
+    def forward(self, im, augment=False, visualize=False):
         # YOLOv5 MultiBackend inference
         b, ch, h, w = im.shape  # batch, channel, height, width
         if self.fp16 and im.dtype != torch.float16:
@@ -521,10 +521,12 @@ class DetectMultiBackend(nn.Module):
             y[..., :4] *= [w, h, w, h]  # xywh normalized to pixels
 
         if isinstance(y, (list, tuple)):
-            y = y[0]
-        if isinstance(y, np.ndarray):
-            y = torch.from_numpy(y).to(self.device)
-        return (y, []) if val else y
+            return self.from_numpy(y[0]) if len(y) == 1 else [self.from_numpy(x) for x in y]
+        else:
+            return self.from_numpy(y)
+
+    def from_numpy(self, x):
+        return torch.from_numpy(x).to(self.device) if isinstance(x, np.ndarray) else x
 
     def warmup(self, imgsz=(1, 3, 640, 640)):
         # Warmup model by running inference once

utils/general.py

@@ -813,6 +813,9 @@ def non_max_suppression(prediction,
          list of detections, on (n,6) tensor per image [xyxy, conf, cls]
     """
 
+    if isinstance(prediction, (list, tuple)):  # YOLOv5 model in validation model, output = (inference_out, loss_out)
+        prediction = prediction[0]  # select only inference output
+
     bs = prediction.shape[0]  # batch size
     nc = prediction.shape[2] - 5  # number of classes
     xc = prediction[..., 4] > conf_thres  # candidates

val.py

@@ -204,11 +204,11 @@ def run(
 
         # Inference
         with dt[1]:
-            out, train_out = model(im) if training else model(im, augment=augment, val=True)  # inference, loss outputs
+            out, train_out = model(im) if compute_loss else (model(im, augment=augment), None)
 
         # Loss
         if compute_loss:
-            loss += compute_loss([x.float() for x in train_out], targets)[1]  # box, obj, cls
+            loss += compute_loss(train_out, targets)[1]  # box, obj, cls
 
         # NMS
         targets[:, 2:] *= torch.tensor((width, height, width, height), device=device)  # to pixels