error on training

[vedangmatey]

When I run train_val.py i get the following error I am using google colab

ValueError: in user code:

/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:806 train_function  *
    return step_function(self, iterator)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:796 step_function  **
    outputs = model.distribute_strategy.run(run_step, args=(data,))
/usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:1211 run
    return self._extended.call_for_each_replica(fn, args=args, kwargs=kwargs)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:2585 call_for_each_replica
    return self._call_for_each_replica(fn, args, kwargs)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:2945 _call_for_each_replica
    return fn(*args, **kwargs)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:789 run_step  **
    outputs = model.train_step(data)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:757 train_step
    self.trainable_variables)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:2737 _minimize
    trainable_variables))
/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/optimizer_v2/optimizer_v2.py:562 _aggregate_gradients
    filtered_grads_and_vars = _filter_grads(grads_and_vars)
/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/optimizer_v2/optimizer_v2.py:1271 _filter_grads
    ([v.name for _, v in grads_and_vars],))

ValueError: No gradients provided for any variable: ['embedding/embeddings:0', 'dense/kernel:0', 'dense/bias:0', 'lstm/lstm_cell/kernel:0', 'lstm/lstm_cell/recurrent_kernel:0', 'lstm/lstm_cell/bias:0', 'time_distributed/kernel:0', 'time_distributed/bias:0', 'bidirectional/forward_lstm_1/lstm_cell_2/kernel:0', 'bidirectional/forward_lstm_1/lstm_cell_2/recurrent_kernel:0', 'bidirectional/forward_lstm_1/lstm_cell_2/bias:0', 'bidirectional/backward_lstm_1/lstm_cell_3/kernel:0', 'bidirectional/backward_lstm_1/lstm_cell_3/recurrent_kernel:0', 'bidirectional/backward_lstm_1/lstm_cell_3/bias:0', 'dense_2/kernel:0', 'dense_2/bias:0'].

[dabasajay]

It's a Keras version issue. Please make sure that you're using the right version of libraries as mentioned in the requirements section in Readme.md file. My code was tested on Tensorflow - 1.13.1 & Keras - 2.2.4.