Can embeddings be compressed?

Yes, embeddings can be compressed. Embeddings are numerical representations of data (like text, images, or audio) in high-dimensional vector spaces. While these vectors capture rich semantic information, their size can become impractical for storage, transmission, or real-time processing. Compression techniques reduce the dimensionality or storage requirements of embeddings while preserving their usefulness for downstream tasks. Common methods include dimensionality reduction, quantization, and specialized encoding schemes. For example, a 1024-dimensional embedding might be compressed to 128 dimensions or stored using fewer bits per value without significantly degrading performance in tasks like similarity search or classification.

One practical approach to compression is dimensionality reduction. Techniques like Principal Component Analysis (PCA) or random projection identify and retain the most informative dimensions of an embedding. For instance, if an embedding has 300 dimensions, PCA might project it into a 50-dimensional space that still captures 95% of the original variance. Quantization is another method, where floating-point values in embeddings are converted to lower-precision representations (e.g., from 32-bit floats to 8-bit integers). This reduces storage size by 75% while maintaining approximate similarity relationships. Libraries like FAISS (Facebook AI Similarity Search) use quantization to enable efficient storage and retrieval of compressed embeddings in large-scale systems.

Developers can also use task-specific compression. For example, in natural language processing, distilled language models like DistilBERT produce smaller embeddings by training a compact model to mimic the behavior of a larger one. Alternatively, binary hashing techniques convert embeddings into compact binary codes, enabling fast bitwise operations for similarity comparisons. When implementing compression, it’s critical to evaluate the trade-offs: aggressive compression may save space but harm task accuracy. A/B testing or metrics like recall@k (for retrieval tasks) can help determine the optimal balance. Tools like scikit-learn for PCA, TensorFlow Lite for quantization, or PyTorch’s model distillation utilities provide accessible pathways to integrate compression into embedding pipelines.