tblock"><p>This page describes the <em>Stochastic Dual Coordinate Ascent</em> (SDCA) linear SVM solver. Please see <a class="el" href="svm.html">Support Vector Machines (SVM)</a> for an overview of VLFeat SVM support.</p>
<p>SDCA maximizes the dual SVM objective (see <a class="el" href="svm-advanced.html#svm-dual-problem">Dual problem</a> for a derivation of this expression):</p>
<p class="formulaDsp">
\[ D(\balpha) = - \frac{1}{2\lambda n^2} \balpha^\top X^\top X \balpha + \frac{1}{n} \sum_{i=1}^n - \ell_i