Sequence Classification Using Hugging Face Transformers Library


Today, I'll be discussing the Sequence Classification in Machine Learning.


What is Classification?

Before going deep into sequence classification, let's understand the fundamentals of classification. In machine learning, classification involves categorizing data into distinct classes or categories based on certain features or attributes. For example, classifying emails as spam or non-spam, identifying whether an image contains a cat or a dog, or predicting whether a transaction is fraudulent or legitimate are all examples of classification tasks.

Also, read these articles:

  1. What is Hugging Face: Getting Started With Hugging Face
  2. Models in Hugging Face: How To Get Started With Hugging Face Models?
  3. Load Models from Hugging Face: How To Load A Pre-trained Model From Hugging Face?

What is Sequence Classification?

Machines are capable of understanding and classifying many sorts of data in a series using the process known as sequence classification. Consider it in the same manner that you would identify each sentence in a phrase or the various intervals in a time series. When working with machine learning and artificial intelligence, this becomes an essential task to do.

Why do we write AutoModelForSequenceClassification?

from transformers import AutoTokenizer, AutoModelForSequenceClassification

The AutoModelForSequenceClassification is a class specifically designed for sequence classification tasks. Sequence classification tasks involve taking an input sequence (e.g., a sentence or paragraph) and classifying it into one or more categories or labels. By using AutoModelForSequenceClassification, we can directly access and use a pre-trained model that has already learned how to perform sequence classification. This saves the time and computational resources required to train such models from scratch. Hugging Face offers a wide range of pre-trained models, and this import statement allows us to choose the appropriate one for sequence classification.

The AutoModelForSequenceClassification import statement allows us to easily access pre-trained models optimized for classifying sequences, making it simpler to perform tasks like sentiment analysis, text categorization, and intent recognition with high accuracy and efficiency.

The input sequences are the sentences that you want the model to classify, and the labels are the categories or classes to which each sentence belongs. The goal of the sequence classification model is to learn from this training data and be able to correctly predict the label (category) for new sentences it has never seen before

When importing models from Hugging Face's Transformers library, you can use different classes based on the specific NLP task you want to perform. The AutoModelForSequenceClassification class is suitable for sequence classification tasks, but there are other classes you can use for different tasks. Here are some of the common ones

1. Text Classification

  • AutoModelForSequenceClassification- Used for sequence classification tasks (as discussed earlier).
  • AutoModelForTokenClassification- Used for token-level classification tasks, such as Named Entity Recognition (NER), where you want to classify individual tokens (words or subwords) within a sequence.

2. Question Answering

  • AutoModelForQuestionAnswering- Used for question-answering tasks, where the model takes a question and a context paragraph and predicts the answer span within the context.

3. Language Modeling

  • AutoModelForCausalLM- Used for causal language modeling, where the model generates text sequentially in an autoregressive manner (e.g., GPT-3).
  • AutoModelForMaskedL- Used for masked language modeling, where the model predicts masked words in a sentence (e.g., BERT).

4. Translation

  • AutoModelForSeq2SeqLM- Used for sequence-to-sequence tasks, like machine translation, summarization, and text generation.

5. Conversation

  • AutoModelForCausalLM- Also used for conversation tasks, where the model generates responses in a chatbot-like interaction.

6. Speech Recognition

  • AutoModelForCTC- Used for Connectionist Temporal Classification tasks, which are common in speech recognition.

7. Image Segmentation

  • AutoModelForImageSegmentation- Used for image segmentation tasks, where the model assigns a label to each pixel in an image to identify objects or regions.

Remember, the specific class you should use depends on the task you want to perform. Hugging Face's Transformers library provides a wide range of pre-trained models, and you can select the appropriate class based on your project's requirements. Additionally, for each task, there's usually a corresponding tokenizer class (e.g., AutoTokenizerForSequenceClassification, AutoTokenizerForQuestionAnswering etc.) that works in conjunction with the model for tokenization and preprocessing.


In summary, sequence classification plays a crucial role in NLP, enabling machines to understand and categorize sequences of data effectively. With the aid of Hugging Face's Transformers library and its specialized classes, beginners can embark on their NLP journey with confidence, harnessing the power of pre-trained models for diverse classification tasks.

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