[BUG Fix]Fix 3 bugs for Adam-Mini (#257)

* Update adam_mini.py

* Update adam_mini.py

* Update adam_mini.py

Author: sdbds

pytorch_optimizer/optimizer/adam_mini.py

@@ -246,16 +246,18 @@ def step_lefts(
         if state['reduced']:
             dist.all_reduce(tmp_lr, op=dist.ReduceOp.SUM)
 
-        tmp_lr.div_(state['dim'])
+        tmp_lr.div_(state['dimension'])
 
         m, v = state['m'], state['v_mean']
 
         m.lerp_(grad, weight=1.0 - beta1)
-        v.mul_(beta2).add_(tmp_lr, value=1.0 - beta2)
+        v.mul_(beta2).add_(tmp_lr, alpha=1.0 - beta2)
 
         h = (v.sqrt() / bias_correction2_sq).add_(eps)
 
-        update = 1 / (bias_correction1 * h).mul_(m)
+        stepsize = (1 / bias_correction1) / h
+
+        update = m * stepsize
 
         p.add_(update, alpha=-lr)