Add anneal-eps argument

Summary: Used in fairspeq/train.py

Reviewed By: myleott, yqwangustc

Differential Revision: D14841512

fbshipit-source-id: 02fd7b58841c32e2797e3159e65f2bef36f02da1

fairseq/optim/adadelta.py

@@ -23,6 +23,7 @@ class Adadelta(FairseqOptimizer):
                             help='coefficient used for computing a running average of squared gradients')
         parser.add_argument('--adadelta-eps', type=float, default=1e-6, metavar='EPS',
                             help='term added to the denominator to improve numerical stability')
+        parser.add_argument('--anneal-eps', action='store_true', help='flag to anneal eps')
 
     @property
     def optimizer_config(self):