Add ConfusionMatrix `normalize=True` flag (#3586)

utils/metrics.py

@@ -158,11 +158,12 @@ class ConfusionMatrix:
     def matrix(self):
         return self.matrix
 
-    def plot(self, save_dir='', names=()):
+    def plot(self, normalize=True, save_dir='', names=()):
         try:
             import seaborn as sn
-
-            array = self.matrix / (self.matrix.sum(0).reshape(1, self.nc + 1) + 1E-6)  # normalize
+            
+            if normalize:
+                array = self.matrix / (self.matrix.sum(0).reshape(1, self.nc + 1) + 1E-6)  # normalize columns
             array[array < 0.005] = np.nan  # don't annotate (would appear as 0.00)
 
             fig = plt.figure(figsize=(12, 9), tight_layout=True)