Vec2Doc: Transforming Dense Vectors into Sparse Representations for Efficient Information Retrieval

Fabio Carrara, Claudio Gennaro, Lucia Vadicamo, Giuseppe Amato

Abstract: The rapid development of deep learning and artificial intelligence has transformed our approach to solving scientific problems across various domains, including computer vision, natural language processing, and automatic content generation. Information retrieval (IR) has also experienced significant advancements, with natural language understanding and multimodal content analysis enabling accurate information retrieval. However, the widespread adoption of neural networks has also influenced the focus of IR problem-solving, which nowadays predominantly relies on evaluating the similarity of dense vectors derived from the latent spaces of deep neural networks. Nevertheless, the challenges of conducting similarity searches on large-scale databases with billions of vectors persist. Traditional IR approaches use inverted indices and vector space models, which work well with sparse vectors. In this paper, we propose Vec2Doc, a novel method that converts dense vectors into sparse integer vectors, allowing for the use of inverted indices. Preliminary experimental evaluation shows a promising solution for large-scale vector-based IR problems.