10-variational_rnn_dropout-overflow.patch

--- tensorflow/contrib/rnn/python/ops/core_rnn_cell_impl.py.orig        2017-05-08 17:02:53.971000000 +0900
+++ tensorflow/contrib/rnn/python/ops/core_rnn_cell_impl.py     2017-05-08 17:39:43.810067656 +0900
@@ -558,9 +558,13 @@
   return nest.map_structure(enumerated_fn, *args, **kwargs)
 
 
+VRDV_MIN, VRDV_MAX = 1.0e-30, 1.0e30 # XXX clip boundary for variational_rnn_dropout
+
+
 class DropoutWrapper(RNNCell):
   """Operator adding dropout to inputs and outputs of the given cell."""
 
+
   def __init__(self, cell, input_keep_prob=1.0, output_keep_prob=1.0,
                state_keep_prob=1.0, variational_recurrent=False,
                input_size=None, dtype=None, seed=None):
@@ -685,7 +689,15 @@
 
     # 0. if [keep_prob, 1.0) and 1. if [1.0, 1.0 + keep_prob)
     binary_tensor = math_ops.floor(random_tensor)
-    ret = math_ops.div(value, keep_prob) * binary_tensor
+
+
+    # ret = math_ops.div(value, keep_prob) * binary_tensor # XXX FIXME/--shr overflow??
+
+
+    value_ = clip_ops.clip_by_value(value, VRDV_MIN, VRDV_MAX)
+    ret = math_ops.div(value_, keep_prob) * binary_tensor
+
+
     ret.set_shape(value.get_shape())
     return ret