{
  "id": 218676,
  "title": "ValueError: Asked to retrieve element 0, but the Sequence has length 0",
  "url": "/competitions/vinbigdata-chest-xray-abnormalities-detection/discussion/218676",
  "author_name": "Gayathri Nagarajan",
  "post_date": "2021-02-11T14:50:22.463000",
  "votes": 1,
  "comment_count": 0,
  "views": 0,
  "content": "<p>Hi Team</p>\n<p>Iam trying to model for chest x rays similar to the code I used for cassava leaf<a href=\"https://www.kaggle.com/gayathrirprog/cassava-comp-keras-image-processing-conv-2d?scriptVersionId=52532625\" target=\"_blank\"> disease detection</a></p>\n<p>For the below code, I get the error :</p>\n<h1>fit model</h1>\n<p>history % fit_generator(<br>\n    train_generator,<br>\n    steps_per_epoch = round(nrow(y_train) / batch_size),<br>\n    epochs = nb_epochs,<br>\n   # callbacks = callback_list, #callback to update cylic lr<br>\n    callbacks = list(check_point, reduce_lr), <br>\n    validation_data = validation_generator,<br>\n    validation_step = round(nrow(y_valid) / batch_size)<br>\n)</p>\n<p><strong>Error</strong><br>\nError in py_call_impl(callable, dots$args, dots$keywords): ValueError: Asked to retrieve element 0, but the Sequence has length 0</p>\n<p>Detailed traceback: <br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/util/deprecation.py\", line 324, in new_func<br>\n    return func(*args, **kwargs)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1829, in fit_generator<br>\n    initial_epoch=initial_epoch)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 108, in _method_wrapper<br>\n    return method(self, *args, **kwargs)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1063, in fit<br>\n    steps_per_execution=self._steps_per_execution)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 1117, in <strong>init</strong><br>\n    model=model)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 916, in <strong>init</strong><br>\n    **kwargs)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 786, in <strong>init</strong><br>\n    peek, x = self._peek_and_restore(x)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 920, in _peek_and_restore<br>\n    return x[0], x<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/keras_preprocessing/image/iterator.py\", line 57, in <strong>getitem</strong><br>\n    length=len(self)))</p>\n<p>=====================</p>\n<p>Any ideas where I would be going wrong?</p>\n<p>Regards<br>\nGayathri</p>",
  "messages": [
    {
      "id": 1196673,
      "postDate": "2021-02-11T14:50:22.463Z",
      "content": "<p>Hi Team</p>\n<p>Iam trying to model for chest x rays similar to the code I used for cassava leaf<a href=\"https://www.kaggle.com/gayathrirprog/cassava-comp-keras-image-processing-conv-2d?scriptVersionId=52532625\" target=\"_blank\"> disease detection</a></p>\n<p>For the below code, I get the error :</p>\n<h1>fit model</h1>\n<p>history % fit_generator(<br>\n    train_generator,<br>\n    steps_per_epoch = round(nrow(y_train) / batch_size),<br>\n    epochs = nb_epochs,<br>\n   # callbacks = callback_list, #callback to update cylic lr<br>\n    callbacks = list(check_point, reduce_lr), <br>\n    validation_data = validation_generator,<br>\n    validation_step = round(nrow(y_valid) / batch_size)<br>\n)</p>\n<p><strong>Error</strong><br>\nError in py_call_impl(callable, dots$args, dots$keywords): ValueError: Asked to retrieve element 0, but the Sequence has length 0</p>\n<p>Detailed traceback: <br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/util/deprecation.py\", line 324, in new_func<br>\n    return func(*args, **kwargs)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1829, in fit_generator<br>\n    initial_epoch=initial_epoch)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 108, in _method_wrapper<br>\n    return method(self, *args, **kwargs)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1063, in fit<br>\n    steps_per_execution=self._steps_per_execution)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 1117, in <strong>init</strong><br>\n    model=model)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 916, in <strong>init</strong><br>\n    **kwargs)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 786, in <strong>init</strong><br>\n    peek, x = self._peek_and_restore(x)<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 920, in _peek_and_restore<br>\n    return x[0], x<br>\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/keras_preprocessing/image/iterator.py\", line 57, in <strong>getitem</strong><br>\n    length=len(self)))</p>\n<p>=====================</p>\n<p>Any ideas where I would be going wrong?</p>\n<p>Regards<br>\nGayathri</p>",
      "rawMarkdown": "Hi Team\n\nIam trying to model for chest x rays similar to the code I used for cassava leaf[ disease detection](https://www.kaggle.com/gayathrirprog/cassava-comp-keras-image-processing-conv-2d?scriptVersionId=52532625)\n\nFor the below code, I get the error :\n#fit model\nhistory <- model %>% fit_generator(\n    train_generator,\n    steps_per_epoch = round(nrow(y_train) / batch_size),\n    epochs = nb_epochs,\n   # callbacks = callback_list, #callback to update cylic lr\n    callbacks = list(check_point, reduce_lr), \n    validation_data = validation_generator,\n    validation_step = round(nrow(y_valid) / batch_size)\n)\n\n**Error**\nError in py_call_impl(callable, dots$args, dots$keywords): ValueError: Asked to retrieve element 0, but the Sequence has length 0\n\nDetailed traceback: \n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/util/deprecation.py\", line 324, in new_func\n    return func(*args, **kwargs)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1829, in fit_generator\n    initial_epoch=initial_epoch)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 108, in _method_wrapper\n    return method(self, *args, **kwargs)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1063, in fit\n    steps_per_execution=self._steps_per_execution)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 1117, in __init__\n    model=model)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 916, in __init__\n    **kwargs)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 786, in __init__\n    peek, x = self._peek_and_restore(x)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 920, in _peek_and_restore\n    return x[0], x\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/keras_preprocessing/image/iterator.py\", line 57, in __getitem__\n    length=len(self)))\n\n=====================\n\nAny ideas where I would be going wrong?\n\nRegards\nGayathri\n\n\n\n",
      "votes": 1
    }
  ],
  "comments": [],
  "raw_markdown_by_id": {
    "1196673": "Hi Team\n\nIam trying to model for chest x rays similar to the code I used for cassava leaf[ disease detection](https://www.kaggle.com/gayathrirprog/cassava-comp-keras-image-processing-conv-2d?scriptVersionId=52532625)\n\nFor the below code, I get the error :\n#fit model\nhistory <- model %>% fit_generator(\n    train_generator,\n    steps_per_epoch = round(nrow(y_train) / batch_size),\n    epochs = nb_epochs,\n   # callbacks = callback_list, #callback to update cylic lr\n    callbacks = list(check_point, reduce_lr), \n    validation_data = validation_generator,\n    validation_step = round(nrow(y_valid) / batch_size)\n)\n\n**Error**\nError in py_call_impl(callable, dots$args, dots$keywords): ValueError: Asked to retrieve element 0, but the Sequence has length 0\n\nDetailed traceback: \n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/util/deprecation.py\", line 324, in new_func\n    return func(*args, **kwargs)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1829, in fit_generator\n    initial_epoch=initial_epoch)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 108, in _method_wrapper\n    return method(self, *args, **kwargs)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/training.py\", line 1063, in fit\n    steps_per_execution=self._steps_per_execution)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 1117, in __init__\n    model=model)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 916, in __init__\n    **kwargs)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 786, in __init__\n    peek, x = self._peek_and_restore(x)\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/tensorflow/python/keras/engine/data_adapter.py\", line 920, in _peek_and_restore\n    return x[0], x\n  File \"/usr/local/share/.virtualenvs/r-reticulate/lib/python3.7/site-packages/keras_preprocessing/image/iterator.py\", line 57, in __getitem__\n    length=len(self)))\n\n=====================\n\nAny ideas where I would be going wrong?\n\nRegards\nGayathri\n\n\n\n"
  }
}