http://programmer.ie/tags/ann/ Recent content in ANN on Programmer.ie: Modern AI programming Hugo en-us Mon, 07 Sep 2026 11:00:00 +0000 http://programmer.ie/books/embeddings-from-first-principles/09-chapter/ Mon, 07 Sep 2026 11:00:00 +0000 http://programmer.ie/books/embeddings-from-first-principles/09-chapter/ <p><em>Part III — Retrieval Is an Experiment</em></p> <h2 id="retrieval-in-four-lines">Retrieval in four lines</h2> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-python" data-lang="python"><span style="display:flex;"><span>query_vec <span style="color:#f92672">=</span> embed(query) <span style="color:#75715e"># one vector</span> </span></span><span style="display:flex;"><span>scores <span style="color:#f92672">=</span> corpus_vecs <span style="color:#f92672">@</span> query_vec <span style="color:#75715e"># one dot product per document</span> </span></span><span style="display:flex;"><span>order <span style="color:#f92672">=</span> np<span style="color:#f92672">.</span>argsort(<span style="color:#f92672">-</span>scores) <span style="color:#75715e"># sort, descending</span> </span></span><span style="display:flex;"><span>results <span style="color:#f92672">=</span> [corpus[i] <span style="color:#66d9ef">for</span> i <span style="color:#f92672">in</span> order[:k]] <span style="color:#75715e"># take the top k</span> </span></span></code></pre></div><p>That is the entire primitive. Everything a vector database adds — indexes, quantization, sharding, filtering — is an optimization or an operational convenience around these four lines. Understand them completely before adding anything.</p> <blockquote> <p><strong>What exactly is a retrieval system deciding, and which of its parameters change the answer rather than just the speed?</strong></p>