FIX: Internally cast to required DType (#659)

* FIX: Internally cast to required DType
* Add pylint disable for unscriptable-object bug

Author: Squadrick

tensorflow_addons/text/crf.py

@@ -38,6 +38,8 @@ def crf_sequence_score(inputs, tag_indices, sequence_lengths,
     Returns:
       sequence_scores: A [batch_size] vector of unnormalized sequence scores.
     """
+    tag_indices = tf.cast(tag_indices, dtype=tf.int32)
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
 
     # If max_seq_len is 1, we skip the score calculation and simply gather the
     # unary potentials of the single tag.
@@ -92,19 +94,19 @@ def crf_multitag_sequence_score(inputs, tag_bitmap, sequence_lengths,
     Returns:
       sequence_scores: A [batch_size] vector of unnormalized sequence scores.
     """
+    tag_bitmap = tf.cast(tag_bitmap, dtype=tf.bool)
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
+    filtered_inputs = tf.where(tag_bitmap, inputs,
+                               tf.fill(tf.shape(inputs), float("-inf")))
 
     # If max_seq_len is 1, we skip the score calculation and simply gather the
     # unary potentials of all active tags.
     def _single_seq_fn():
-        filtered_inputs = tf.where(tag_bitmap, inputs,
-                                   tf.fill(tf.shape(inputs), float("-inf")))
         return tf.reduce_logsumexp(
             filtered_inputs, axis=[1, 2], keepdims=False)
 
     def _multi_seq_fn():
         # Compute the logsumexp of all scores of sequences matching the given tags.
-        filtered_inputs = tf.where(tag_bitmap, inputs,
-                                   tf.fill(tf.shape(inputs), float("-inf")))
         return crf_log_norm(
             inputs=filtered_inputs,
             sequence_lengths=sequence_lengths,
@@ -127,6 +129,7 @@ def crf_log_norm(inputs, sequence_lengths, transition_params):
     Returns:
       log_norm: A [batch_size] vector of normalizers for a CRF.
     """
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
     # Split up the first and rest of the inputs in preparation for the forward
     # algorithm.
     first_input = tf.slice(inputs, [0, 0, 0], [-1, 1, -1])
@@ -183,10 +186,12 @@ def crf_log_likelihood(inputs,
       transition_params: A [num_tags, num_tags] transition matrix. This is
           either provided by the caller or created in this function.
     """
-    # Get shape information.
     num_tags = inputs.shape[2]
 
-    # Get the transition matrix if not provided.
+    # cast type to handle different types
+    tag_indices = tf.cast(tag_indices, dtype=tf.int32)
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
+
     if transition_params is None:
         initializer = tf.keras.initializers.GlorotUniform()
         transition_params = tf.Variable(
@@ -211,6 +216,9 @@ def crf_unary_score(tag_indices, sequence_lengths, inputs):
     Returns:
       unary_scores: A [batch_size] vector of unary scores.
     """
+    tag_indices = tf.cast(tag_indices, dtype=tf.int32)
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
+
     batch_size = tf.shape(inputs)[0]
     max_seq_len = tf.shape(inputs)[1]
     num_tags = tf.shape(inputs)[2]
@@ -245,7 +253,9 @@ def crf_binary_score(tag_indices, sequence_lengths, transition_params):
     Returns:
       binary_scores: A [batch_size] vector of binary scores.
     """
-    # Get shape information.
+    tag_indices = tf.cast(tag_indices, dtype=tf.int32)
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
+
     num_tags = tf.shape(transition_params)[0]
     num_transitions = tf.shape(tag_indices)[1] - 1
 
@@ -288,6 +298,7 @@ def crf_forward(inputs, state, transition_params, sequence_lengths):
       new_alphas: A [batch_size, num_tags] matrix containing the
           new alpha values.
     """
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
 
     sequence_lengths = tf.maximum(
         tf.constant(0, dtype=sequence_lengths.dtype), sequence_lengths - 2)
@@ -399,6 +410,7 @@ def crf_decode_forward(inputs, state, transition_params, sequence_lengths):
       backpointers: A [batch_size, num_tags] matrix of backpointers.
       new_state: A [batch_size, num_tags] matrix of new score values.
     """
+    sequence_lengths = tf.cast(sequence_lengths, dtype=tf.int32)
     mask = tf.sequence_mask(sequence_lengths, tf.shape(inputs)[1])
     crf_fwd_cell = CrfDecodeForwardRnnCell(transition_params)
     crf_fwd_layer = tf.keras.layers.RNN(
@@ -446,6 +458,7 @@ def crf_decode(potentials, transition_params, sequence_length):
                   Contains the highest scoring tag indices.
       best_score: A [batch_size] vector, containing the score of `decode_tags`.
     """
+    sequence_length = tf.cast(sequence_length, dtype=tf.int32)
 
     # If max_seq_len is 1, we skip the algorithm and simply return the argmax tag
     # and the max activation.

tensorflow_addons/text/crf_test.py

@@ -209,8 +209,11 @@ def testCrfLogLikelihood(self):
         transition_params = np.array([[-3, 5, -2], [3, 4, 1], [1, 2, 1]],
                                      dtype=np.float32)
         sequence_lengths = np.array(3, dtype=np.int32)
+        # TODO: https://github.com/PyCQA/pylint/issues/3139
+        # pylint: disable=E1136
         num_words = inputs.shape[0]
         num_tags = inputs.shape[1]
+        # pylint: enable=E1136
         all_sequence_log_likelihoods = []
 
         # Make sure all probabilities sum to 1.
@@ -241,8 +244,11 @@ def testViterbiDecode(self):
         transition_params = np.array([[-3, 5, -2], [3, 4, 1], [1, 2, 1]],
                                      dtype=np.float32)
         sequence_lengths = np.array(3, dtype=np.int32)
+        # TODO: https://github.com/PyCQA/pylint/issues/3139
+        # pylint: disable=E1136
         num_words = inputs.shape[0]
         num_tags = inputs.shape[1]
+        # pylint: enable=E1136
 
         all_sequence_scores = []
         all_sequences = []
@@ -347,6 +353,16 @@ def testCrfDecodeZeroSeqLength(self):
         self.assertEqual(len(tf_tags.shape), 2)
         self.assertEqual(len(tf_scores.shape), 1)
 
+    def testDifferentDtype(self):
+        inputs = np.ones([16, 20, 5], dtype=np.float32)
+        tags = tf.convert_to_tensor(np.ones([16, 20], dtype=np.int64))
+        seq_lens = np.ones([
+            16,
+        ], dtype=np.int64) * 20
+
+        loss, _ = text.crf_log_likelihood(
+            inputs=inputs, tag_indices=tags, sequence_lengths=seq_lens)
+
 
 if __name__ == "__main__":
     tf.test.main()