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ValueError: You must include at least one label and at least one sequence

Time:12-10

I'm using this Notebook, where section Apply DocumentClassifier is altered as below.

Jupyter Labs, kernel: conda_mxnet_latest_p37.

Error appears to be an ML standard practice response. However, I pass/ create the same parameter and the variable names as the original code. So it's something to do with their values in my code.


My Code:

with open('filt_gri.txt', 'r') as filehandle:
    tags = [current_place.rstrip() for current_place in filehandle.readlines()]

doc_classifier = TransformersDocumentClassifier(model_name_or_path="cross-encoder/nli-distilroberta-base",
                                                task="zero-shot-classification",
                                                labels=tags,
                                                batch_size=16)

# convert to Document using a fieldmap for custom content fields the classification should run on
docs_to_classify = [Document.from_dict(d) for d in docs_sliding_window]

# classify using gpu, batch_size makes sure we do not run out of memory
classified_docs = doc_classifier.predict(docs_to_classify)

# let's see how it looks: there should be a classification result in the meta entry containing labels and scores.
print(classified_docs[0].to_dict())

all_docs = convert_files_to_dicts(dir_path=doc_dir)

preprocessor_sliding_window = PreProcessor(split_overlap=3,
                                           split_length=10,
                                           split_respect_sentence_boundary=False,
                                           split_by='passage')

Output:

INFO - haystack.modeling.utils -  Using devices: CUDA
INFO - haystack.modeling.utils -  Number of GPUs: 1
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-11-77eb98038283> in <module>
     14 
     15 # classify using gpu, batch_size makes sure we do not run out of memory
---> 16 classified_docs = doc_classifier.predict(docs_to_classify)
     17 
     18 # let's see how it looks: there should be a classification result in the meta entry containing labels and scores.

~/anaconda3/envs/mxnet_latest_p37/lib/python3.7/site-packages/haystack/nodes/document_classifier/transformers.py in predict(self, documents)
    137         batches = self.get_batches(texts, batch_size=self.batch_size)
    138         if self.task == 'zero-shot-classification':
--> 139             batched_predictions = [self.model(batch, candidate_labels=self.labels, truncation=True) for batch in batches]
    140         elif self.task == 'text-classification':
    141             batched_predictions = [self.model(batch, return_all_scores=self.return_all_scores, truncation=True) for batch in batches]

~/anaconda3/envs/mxnet_latest_p37/lib/python3.7/site-packages/haystack/nodes/document_classifier/transformers.py in <listcomp>(.0)
    137         batches = self.get_batches(texts, batch_size=self.batch_size)
    138         if self.task == 'zero-shot-classification':
--> 139             batched_predictions = [self.model(batch, candidate_labels=self.labels, truncation=True) for batch in batches]
    140         elif self.task == 'text-classification':
    141             batched_predictions = [self.model(batch, return_all_scores=self.return_all_scores, truncation=True) for batch in batches]

~/anaconda3/envs/mxnet_latest_p37/lib/python3.7/site-packages/transformers/pipelines/zero_shot_classification.py in __call__(self, sequences, candidate_labels, hypothesis_template, multi_label, **kwargs)
    151             sequences = [sequences]
    152 
--> 153         outputs = super().__call__(sequences, candidate_labels, hypothesis_template)
    154         num_sequences = len(sequences)
    155         candidate_labels = self._args_parser._parse_labels(candidate_labels)

~/anaconda3/envs/mxnet_latest_p37/lib/python3.7/site-packages/transformers/pipelines/base.py in __call__(self, *args, **kwargs)
    758 
    759     def __call__(self, *args, **kwargs):
--> 760         inputs = self._parse_and_tokenize(*args, **kwargs)
    761         return self._forward(inputs)
    762 

~/anaconda3/envs/mxnet_latest_p37/lib/python3.7/site-packages/transformers/pipelines/zero_shot_classification.py in _parse_and_tokenize(self, sequences, candidate_labels, hypothesis_template, padding, add_special_tokens, truncation, **kwargs)
     92         Parse arguments and tokenize only_first so that hypothesis (label) is not truncated
     93         """
---> 94         sequence_pairs = self._args_parser(sequences, candidate_labels, hypothesis_template)
     95         inputs = self.tokenizer(
     96             sequence_pairs,

~/anaconda3/envs/mxnet_latest_p37/lib/python3.7/site-packages/transformers/pipelines/zero_shot_classification.py in __call__(self, sequences, labels, hypothesis_template)
     25     def __call__(self, sequences, labels, hypothesis_template):
     26         if len(labels) == 0 or len(sequences) == 0:
---> 27             raise ValueError("You must include at least one label and at least one sequence.")
     28         if hypothesis_template.format(labels[0]) == hypothesis_template:
     29             raise ValueError(

ValueError: You must include at least one label and at least one sequence.

Original Code:

doc_classifier = TransformersDocumentClassifier(model_name_or_path="cross-encoder/nli-distilroberta-base",
    task="zero-shot-classification",
    labels=["music", "natural language processing", "history"],
    batch_size=16
)

# ----------

# convert to Document using a fieldmap for custom content fields the classification should run on
docs_to_classify = [Document.from_dict(d) for d in docs_sliding_window]

# ----------

# classify using gpu, batch_size makes sure we do not run out of memory
classified_docs = doc_classifier.predict(docs_to_classify)

# ----------

# let's see how it looks: there should be a classification result in the meta entry containing labels and scores.
print(classified_docs[0].to_dict())

Please let me know if there is anything else I should add to post/ clarify.

CodePudding user response:

 Reading official docs and analyzing that the error is generated when calling .predict(docs_to_classify) I could recommend that you try to do basic tests such as using the parameter labels = ["negative", "positive"] , and correct if it is caused by string values of the external file and optionally you should also check where it indicates the use of pipelines.

pipeline = Pipeline()
pipeline.add_node(component=retriever, name="Retriever", inputs=["Query"])
pipeline.add_node(component=doc_classifier, name='DocClassifier', inputs=['Retriever'])
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