How to Train Word2Vec Models Using Python and Gensim

Aug 2, 2022 | Data Science

Welcome to our practical guide on training Word2Vec models! In this article, we’ll walk you through the steps for setting up your environment, preprocessing data, training the model, and analyzing the results using the Python package Gensim. But fear not! We’ll keep things user-friendly with clear explanations at every turn, peppered with some creative analogies to clarify complex concepts.

Setup and Installation

To kick things off, you’ll need to set up your environment so that you can dive into training your Word2Vec models on TED Talk and Wikipedia data.

  • Open a terminal in your lab workstation.
  • Clone the practical repository.
  • Run the following shell script to install Anaconda with Python 3 and the necessary packages:
  • bash install-python.sh
  • Launch Jupyter Notebook by running:
  • ipython notebook
  • Open the practical.ipynb notebook in your browser.

Preliminaries

Now that you have your environment set up, let’s get the data prepared!

Preprocessing the Data

The code already contains a routine for downloading and preprocessing the dataset, which saves you some time.

Think of preprocessing like cleaning a cluttered room before you start decorating. You can’t really appreciate the art (or data) until everything is tidy! In practice, libraries like nltk help with preprocessing, but here we will be using regex via Python’s re module to keep things simple.

Word Frequencies

Next, we need to create a list of the most common words and their occurrence counts. Let’s take a look at the top 40 words. For this, you can utilize:

  • The CountVectorizer class from sklearn.feature_extraction.text.
  • The Counter class from the collections module.

Once you have the data, plot a histogram of the top 1000 words’ counts. The code for an interactive histogram is included in the notebook.

Your task: Show the frequency distribution histogram.

Training Word2Vec

With the data all cleaned up, it’s time to train our Word2Vec model! This is where the magic happens.

Reading is key here: check out the Gensim documentation for using the Word2Vec class.

Consider training a Word2Vec model like teaching a toddler to speak. You provide them with numerous sentences, and they gradually learn the meanings of words and their relationships through exposure.

Now, as you train:

  • Use embeddings in ℝ^100 with CBOW (this is the default setting).
  • Set min_count=10 to ignore infrequent words.

The training should complete in under half a minute. Once it’s done, check the vocabulary size with:

len(model_ted.vocab)

This should return a vocabulary size of approximately 14,427.

For further experimentation, you can use the most_similar() method to find similar words for “man” and “computer”.

Your tasks:

  • Find a few words with interesting or surprising nearest neighbors.
  • Discover an intriguing cluster in the t-SNE plot.

Optional Exploration

If you’re feeling ambitious, manually retrieve two word vectors and calculate their cosine distance using:

np.dot()
np.linalg.norm()

Check these against the distances generated by Gensim’s built-in functions!

Comparing with WikiText-2 Data

Next up, you’ll repeat the same analysis on the WikiText-2 dataset:

Just like comparing apples to oranges helps you appreciate their differences, you’ll see how embeddings from distinct datasets can yield varied results.

Your tasks:

  • Find a few words with similar nearest neighbors.
  • Identify an interesting cluster in the t-SNE plot.
  • Look for notable differences in the embeddings compared to those learned from the TED Talk data.

Optional: K-Means Clustering

If you’re still eager for more, try diving into k-means clustering using sklearn.cluster.kmeans. Tune the number of clusters until you start uncovering fascinating or meaningful clusters in your data!

Hand-in Instructions

Follow the bolded Handin: prompts in the notebook for what you need to demonstrate. Make sure to show a practical demonstrator to get your responses verified!

Troubleshooting

If you encounter any bumps along the road, here are some tips:

  • Ensure all necessary packages are installed properly.
  • Double-check for any typos in your code.
  • Rerun the preprocessing steps if you run into unexpected issues with data.

For more insights, updates, or to collaborate on AI development projects, stay connected with fxis.ai.

At fxis.ai, we believe that such advancements are crucial for the future of AI, as they enable more comprehensive and effective solutions. Our team is continually exploring new methodologies to push the envelope in artificial intelligence, ensuring that our clients benefit from the latest technological innovations.

Now go on, embrace the curiosity of learning and have fun exploring the world of Word2Vec!

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