Update train.py test batch_size (#2148)

* Update train.py

* Update loss.py

utils/loss.py

@@ -105,8 +105,7 @@ class ComputeLoss:
             BCEcls, BCEobj = FocalLoss(BCEcls, g), FocalLoss(BCEobj, g)
 
         det = model.module.model[-1] if is_parallel(model) else model.model[-1]  # Detect() module
-        self.balance = {3: [3.67, 1.0, 0.43], 4: [3.78, 1.0, 0.39, 0.22], 5: [3.88, 1.0, 0.37, 0.17, 0.10]}[det.nl]
-        # self.balance = [1.0] * det.nl
+        self.balance = {3: [3.67, 1.0, 0.43], 4: [4.0, 1.0, 0.25, 0.06], 5: [4.0, 1.0, 0.25, 0.06, .02]}[det.nl]
         self.ssi = (det.stride == 16).nonzero(as_tuple=False).item()  # stride 16 index
         self.BCEcls, self.BCEobj, self.gr, self.hyp, self.autobalance = BCEcls, BCEobj, model.gr, h, autobalance
         for k in 'na', 'nc', 'nl', 'anchors':