fix bug

Author: zhangbo9674

python/paddle/optimizer/momentum.py

@@ -192,7 +192,7 @@ def __init__(self,
 
  def _update_regularization(self, weight_decay):
  reg_method = ""
- reg_coeff = 0
+ reg_coeff = 0.0
 
  if (isinstance(weight_decay, L2DecayRegularizer)):
  reg_method = "l2_decay"
@@ -306,7 +306,7 @@ def _append_optimize_op(self, block, param_and_grad):
  # the param's regularization has been done before, we avoid do l2decay in momentum.
  elif param.regularizer is not None:
  regularization_method = ""
- regularization_coeff = 0
+ regularization_coeff = 0.0
 
  find_master = self._multi_precision and param_and_grad[
  0].dtype == core.VarDesc.VarType.FP16