Bugfix to LSTMBlockCell and friends: clipping is off by default.

* Rename broken API argu clip_cell boolean to cell_clip value.
* Make default no clipping.

PiperOrigin-RevId: 170960975

tensorflow/contrib/cudnn_rnn/python/ops/cudnn_rnn_ops.py

@@ -65,7 +65,7 @@ class CudnnCompatibleLSTMCell(lstm_ops.LSTMBlockCell):
 
   def __init__(self, num_units, reuse=None):
     super(CudnnCompatibleLSTMCell, self).__init__(
-        num_units, forget_bias=0, clip_cell=False, use_peephole=False,
+        num_units, forget_bias=0, cell_clip=None, use_peephole=False,
         reuse=reuse)
     self._names.update({"scope": "cudnn_compatible_lstm_cell"})
 

tensorflow/contrib/rnn/python/ops/lstm_ops.py

@@ -92,7 +92,7 @@ def _lstm_block_cell(x,
     wco: A `Tensor`. Must have the same type as `x`.
       The weight matrix for output gate peephole connection.
     forget_bias: An optional `float`. Defaults to `1`. The forget gate bias.
-    cell_clip: An optional `float`. Defaults to `3`.
+    cell_clip: An optional `float`. Defaults to `-1` (no clipping).
       Value to clip the 'cs' value to. Disable by setting to negative value.
     use_peephole: An optional `bool`. Defaults to `False`.
       Whether to use peephole weights.
@@ -130,7 +130,7 @@ def _lstm_block_cell(x,
       wcf=wcf,
       b=b,
       forget_bias=forget_bias,
-      cell_clip=cell_clip,
+      cell_clip=cell_clip if cell_clip is not None else -1,
       use_peephole=use_peephole,
       name=name)
   # pylint: enable=protected-access
@@ -162,7 +162,7 @@ def _block_lstm(seq_len_max,
     wcf: A `Tensor`. Must have the same type as `x`.
     wco: A `Tensor`. Must have the same type as `x`.
     forget_bias: An optional `float`. Defaults to `1`.
-    cell_clip: An optional `float`. Defaults to `3`.
+    cell_clip: An optional `float`. Defaults to `-1` (no clipping).
     use_peephole: An optional `bool`. Defaults to `False`.
     name: A name for the operation (optional).
 
@@ -216,7 +216,7 @@ def _block_lstm(seq_len_max,
       wcf=wcf,
       b=b,
       forget_bias=forget_bias,
-      cell_clip=cell_clip,
+      cell_clip=cell_clip if cell_clip is not None else -1,
       name=name,
       use_peephole=use_peephole)
 
@@ -341,7 +341,7 @@ class LSTMBlockCell(rnn_cell_impl.RNNCell):
   def __init__(self,
                num_units,
                forget_bias=1.0,
-               clip_cell=True,
+               cell_clip=None,
                use_peephole=False,
                reuse=None):
     """Initialize the basic LSTM cell.
@@ -349,8 +349,7 @@ class LSTMBlockCell(rnn_cell_impl.RNNCell):
     Args:
       num_units: int, The number of units in the LSTM cell.
       forget_bias: float, The bias added to forget gates (see above).
-      clip_cell: boolean, whether to apply cell clipping. See
-        `_lstm_block_cell()` for details.
+      cell_clip: An optional `float`. Defaults to `-1` (no clipping).
       use_peephole: Whether to use peephole connections or not.
       reuse: (optional) boolean describing whether to reuse variables in an
         existing scope.  If not `True`, and the existing scope already has the
@@ -363,7 +362,7 @@ class LSTMBlockCell(rnn_cell_impl.RNNCell):
     self._num_units = num_units
     self._forget_bias = forget_bias
     self._use_peephole = use_peephole
-    self._clip_cell = clip_cell
+    self._cell_clip = cell_clip if cell_clip is not None else -1
     self._names = {
         "W": "kernel",
         "b": "bias",
@@ -412,7 +411,7 @@ class LSTMBlockCell(rnn_cell_impl.RNNCell):
           wco=wco,
           wcf=wcf,
           forget_bias=self._forget_bias,
-          cell_clip=None if self._clip_cell else -1,
+          cell_clip=self._cell_clip,
           use_peephole=self._use_peephole)
 
       new_state = rnn_cell_impl.LSTMStateTuple(cs, h)
@@ -594,12 +593,12 @@ class LSTMBlockFusedCell(LSTMBlockWrapper):
     Args:
       num_units: int, The number of units in the LSTM cell.
       forget_bias: float, The bias added to forget gates (see above).
-      cell_clip: clip the cell to this value. Defaults to `3`.
+      cell_clip: clip the cell to this value. Default is no cell clipping.
       use_peephole: Whether to use peephole connections or not.
     """
     self._num_units = num_units
     self._forget_bias = forget_bias
-    self._cell_clip = cell_clip
+    self._cell_clip = cell_clip if cell_clip is not None else -1
     self._use_peephole = use_peephole
 
   @property