Introduction to Information Retrieval
Introduction to Information Retrieval
Introduction to Information Retrieval
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
<strong>Introduction</strong> <strong>to</strong> <strong>Information</strong> <strong>Retrieval</strong><br />
Documents as vec<strong>to</strong>rs<br />
• Each document is now represented as a real-valued vec<strong>to</strong>r<br />
of tf-idf weights ∈ R |V|.<br />
• So we have a |V|-dimensional real-valued vec<strong>to</strong>r space.<br />
• Terms are axes of the space.<br />
• Documents are points or vec<strong>to</strong>rs in this space.<br />
• Very high-dimensional: tens of millions of dimensions when<br />
you apply this <strong>to</strong> web search engines<br />
• Each vec<strong>to</strong>r is very sparse - most entries are zero.<br />
34
Change language