index is out of bounds for axis 1 with size 50

[chinmayembedded]

While training handwriting_recognition, I get the following error.

Epoch 1/8

IndexError Traceback (most recent call last)
in
21 history_object = model.fit_generator(train_generator, samples_per_epoch= samples_per_epoch,
22 validation_data=validation_generator,
---> 23 nb_val_samples=nb_val_samples, nb_epoch=nb_epoch, verbose=1, callbacks=callbacks_list)

~/.local/lib/python3.5/site-packages/keras/legacy/interfaces.py in wrapper(*args, **kwargs)
89 warnings.warn('Update your ' + object_name + ' call to the ' +
90 'Keras 2 API: ' + signature, stacklevel=2)
---> 91 return func(*args, **kwargs)
92 wrapper._original_function = func
93 return wrapper

~/.local/lib/python3.5/site-packages/keras/engine/training.py in fit_generator(self, generator, steps_per_epoch, epochs, verbose, callbacks, validation_data, validation_steps, validation_freq, class_weight, max_queue_size, workers, use_multiprocessing, shuffle, initial_epoch)
1730 use_multiprocessing=use_multiprocessing,
1731 shuffle=shuffle,
-> 1732 initial_epoch=initial_epoch)
1733
1734 @interfaces.legacy_generator_methods_support

~/.local/lib/python3.5/site-packages/keras/engine/training_generator.py in fit_generator(model, generator, steps_per_epoch, epochs, verbose, callbacks, validation_data, validation_steps, validation_freq, class_weight, max_queue_size, workers, use_multiprocessing, shuffle, initial_epoch)
183 batch_index = 0
184 while steps_done < steps_per_epoch:
--> 185 generator_output = next(output_generator)
186
187 if not hasattr(generator_output, 'len'):

~/.local/lib/python3.5/site-packages/keras/utils/data_utils.py in get(self)
740 "use_multiprocessing=False, workers > 1."
741 "For more information see issue #1638.")
--> 742 six.reraise(*sys.exc_info())

~/.local/lib/python3.5/site-packages/six.py in reraise(tp, value, tb)
691 if value.traceback is not tb:
692 raise value.with_traceback(tb)
--> 693 raise value
694 finally:
695 value = None

~/.local/lib/python3.5/site-packages/keras/utils/data_utils.py in get(self)
709 try:
710 future = self.queue.get(block=True)
--> 711 inputs = future.get(timeout=30)
712 self.queue.task_done()
713 except mp.TimeoutError:

/usr/lib/python3.5/multiprocessing/pool.py in get(self, timeout)
606 return self._value
607 else:
--> 608 raise self._value
609
610 def _set(self, i, obj):

/usr/lib/python3.5/multiprocessing/pool.py in worker(inqueue, outqueue, initializer, initargs, maxtasks, wrap_exception)
117 job, i, func, args, kwds = task
118 try:
--> 119 result = (True, func(*args, **kwds))
120 except Exception as e:
121 if wrap_exception:

~/.local/lib/python3.5/site-packages/keras/utils/data_utils.py in next_sample(uid)
648 The next value of generator uid.
649 """
--> 650 return six.next(_SHARED_SEQUENCES[uid])
651
652

in generate_data(samples, target_files, batch_size, factor)
59
60 #One hot encode y
---> 61 y_train = to_categorical(y_train, num_classes)
62
63 yield shuffle(X_train, y_train)

~/.local/lib/python3.5/site-packages/keras/utils/np_utils.py in to_categorical(y, num_classes, dtype)
50 n = y.shape[0]
51 categorical = np.zeros((n, num_classes), dtype=dtype)
---> 52 categorical[np.arange(n), y] = 1
53 output_shape = input_shape + (num_classes,)
54 categorical = np.reshape(categorical, output_shape)

IndexError: index 60 is out of bounds for axis 1 with size 50