Published online by Cambridge University Press: 25 August 2021
We obtain a polynomial upper bound on the mixing time $T_{CHR}(\epsilon)$ of the coordinate Hit-and-Run (CHR) random walk on an
$n-$dimensional convex body, where
$T_{CHR}(\epsilon)$ is the number of steps needed to reach within
$\epsilon$ of the uniform distribution with respect to the total variation distance, starting from a warm start (i.e., a distribution which has a density with respect to the uniform distribution on the convex body that is bounded above by a constant). Our upper bound is polynomial in n, R and
$\frac{1}{\epsilon}$, where we assume that the convex body contains the unit
$\Vert\cdot\Vert_\infty$-unit ball
$B_\infty$ and is contained in its R-dilation
$R\cdot B_\infty$. Whether CHR has a polynomial mixing time has been an open question.