fix a bug: change l2 to mse (#570)

* add calc_psnr script

* delete calc_psnr script

* change l2 to mse

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Co-authored-by: Xintao <[email protected]>

Author: LiangbinXie

basicsr/losses/basic_loss.py

@@ -189,7 +189,7 @@ def __init__(self,
         if self.criterion_type == 'l1':
             self.criterion = torch.nn.L1Loss()
         elif self.criterion_type == 'l2':
-            self.criterion = torch.nn.L2loss()
+            self.criterion = torch.nn.MSELoss()
         elif self.criterion_type == 'fro':
             self.criterion = None
         else: