docstr: Test if GPU CTC loss can fallback to the correct algorithm.
docstr_tok: ["Test","if","GPU","CTC","loss","can","fallback","to","the","correct","algorithm","."]
code: def testCtcLossAlgorithmFallback(self):
      """Test if GPU CTC loss can fallback to the correct algorithm."""
      if not test.is_gpu_available():
          self.skipTest("Need GPU for testing.")
      if not context.executing_eagerly():
          self.skipTest("Need eager execution for testing.")
      random_seed.set_random_seed(5)
  
      batch_size = 1
      num_labels = 11777
      max_label_length = 2
      num_frames = 1
  
      labels = random_ops.random_uniform(
          [batch_size, max_label_length],
          minval=1,
          maxval=num_labels,
          dtype=dtypes.int64,
      )
      logits = random_ops.random_uniform(
          [num_frames, batch_size, num_labels]
      )
  
      label_length = random_ops.random_uniform(
          [batch_size],
          minval=1,
          maxval=max_label_length,
          dtype=dtypes.int64,
      )
      logit_length = [num_frames] * batch_size
  
      loss, grad = _ctc_loss_v3(
          labels, logits, label_length, logit_length, True
      )
      ref_loss, ref_grad = _ctc_loss_v3(
          labels, logits, label_length, logit_length, False
      )
  
      self.assertAllClose(loss, ref_loss, atol=1e-6)
      self.assertAllClose(grad, ref_grad, atol=2e-6)
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors_impl
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import random_seed
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import ctc_ops
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.ops import sparse_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the CTCLossTestV3 obj's underlying member method code with example usage: obj.testCtcLossAlgorithmFallback() without return types