!7626 fix for se-resnet50 accurancy

Merge pull request !7626 from qujianwei/master

model_zoo/official/cv/resnet/src/lr_generator.py

@@ -100,8 +100,10 @@ def _generate_cosine_lr(lr_init, lr_end, lr_max, total_steps, warmup_steps):
             lr_inc = (float(lr_max) - float(lr_init)) / float(warmup_steps)
             lr = float(lr_init) + lr_inc * (i + 1)
         else:
-            cosine_decay = 0.5 * (1 + math.cos(math.pi * (i - warmup_steps) / decay_steps))
-            lr = (lr_max - lr_end) * cosine_decay + lr_end
+            linear_decay = (total_steps - i) / decay_steps
+            cosine_decay = 0.5 * (1 + math.cos(math.pi * 2 * 0.47 * i / decay_steps))
+            decayed = linear_decay * cosine_decay + 0.00001
+            lr = lr_max * decayed
         lr_each_step.append(lr)
     return lr_each_step