Simplex ratio test (source code)

= Simplex ratio test
{title2=$\theta=\min_{i:d_i>0}x_i/d_i$}

= Pivot ratio test
{synonym}

In a feasible <simplex basis>, increasing a nonbasic variable by $\theta$ changes basic coordinates to $x-\theta d$. Nonnegativity limits $\theta$ by the smallest ratio $x_i/d_i$ with $d_i>0$; a minimizing coordinate leaves the basis. Ties can leave zero-valued basic variables. This pivot test is distinct from the analytic <ratio test> for series convergence.