Word Analogy Solver
Solve word analogies using vector arithmetic on word embeddings.
Word analogies take the form: "A is to B as C is to ?"
Using word vectors, the answer is the word whose vector is closest to: B−A+C
Input format:
- Line 1: Three words (A B C) — the analogy query
- Line 2: Number of words in vocabulary N
- Lines 3 to N+2: word followed by its embedding vector (space-separated floats)
Output: The word from the vocabulary (excluding A, B, C) whose vector is closest to B - A + C (using cosine similarity).
Example:
king queen man 5 king 1.0 0.5 0.0 queen 0.8 0.6 0.5 man 0.9 0.4 0.0 woman 0.7 0.5 0.5 child 0.2 0.3 0.8
woman
Step 1: Compute target vector target = queen - king + man = [0.8, 0.6, 0.5] - [1.0, 0.5, 0.0] + [0.9, 0.4, 0.0] = [0.7, 0.5, 0.5]
Step 2: Compute cosine similarity with each candidate Candidates (excluding king, queen, man): woman, child
- woman [0.7, 0.5, 0.5]: cos_sim with [0.7, 0.5, 0.5] = 1.0
- child [0.2, 0.3, 0.8]: cos_sim is lower
Answer: woman (highest similarity)
Constraints:
- Exclude the three query words from candidate answers
- Use cosine similarity to find the closest word
- All vectors have the same dimensionality
- There will be a unique best answer
Background Knowledge
Word Embeddings are a fundamental concept in Natural Language Processing (NLP) that represent words as vectors in a high-dimensional space. This allows words with similar meanings to be mapped to nearby points in the vector space. Word embeddings can be learned using various techniques, such as Word2Vec or GloVe, and are essential for many NLP tasks, including text classification, sentiment analysis, and machine translation.
The idea of using vector arithmetic to solve word analogies is based on the concept of vector space models. In these models, words are represented as vectors, and operations like addition and subtraction can be performed on these vectors to capture semantic relationships between words. For example, the vector B−A represents the semantic relationship between words A and B. By adding C to this result, we can find a word that is related to C in the same way that B is related to A.
The cosine similarity measure is commonly used to compare the similarity between two vectors. It is defined as the dot product of the two vectors divided by the product of their magnitudes. Cosine similarity is useful for comparing the orientation of two vectors, rather than their magnitude. In the context of word embeddings, cosine similarity can be used to find the word that is most similar to a given vector, which is essential for solving word analogies.
Algorithm/Approach
The general approach to solving word analogies using vector arithmetic involves the following steps:
- Load the word embeddings for the given vocabulary
- Calculate the vector B−A+C using the given words A, B, and C
- Compare this vector to the word embeddings in the vocabulary using cosine similarity
- Return the word with the highest cosine similarity score, excluding the words A, B, and C
This approach relies on the idea that the vector B−A+C captures the semantic relationship between the words A, B, and C, and that the word with the highest cosine similarity score will be the one that is most similar to this relationship.
Step-by-Step Strategy
To implement the solution, follow these steps:
- Read the input words A, B, and C, and the number of words in the vocabulary N
- Load the word embeddings for the vocabulary, storing each word and its corresponding vector in a data structure (e.g., a dictionary)
- Calculate the vector B−A+C using the word embeddings
- Initialize a variable to store the word with the highest cosine similarity score
- Iterate over the word embeddings in the vocabulary, excluding the words A, B, and C
- For each word, calculate the cosine similarity between its vector and the vector B−A+C
- Update the variable storing the word with the highest cosine similarity score if a higher score is found
- Return the word with the highest cosine similarity score
Common Pitfalls
When implementing the solution, watch out for the following:
- Ensure that the word embeddings are loaded correctly and stored in a suitable data structure
- Verify that the vector calculations are performed correctly, taking into account the dimensions of the word embeddings
- Be careful when iterating over the vocabulary, excluding the words A, B, and C to avoid biasing the results
- Consider using a library or framework that provides efficient implementations of cosine similarity and vector operations
Time & Space Complexity
The time complexity of the solution is O(N * d), where N is the number of words in the vocabulary and d is the dimensionality of the word embeddings. This is because we need to iterate over the vocabulary and perform vector operations for each word. The space complexity is O(N * d), as we need to store the word embeddings in memory. Note that the dimensionality of the word embeddings (d) is typically much larger than the number of words in the vocabulary (N), so the space complexity is dominated by the storage of the word embeddings.