Symp. Comp.
Geo., 1988] and Yap [J. Comp. Sys. Sci., 1990] symbolically
perturb the input to remove singularities. </p>

<p>Merged facets ('<a href="qh-optc.htm#C0">C-0</a>') handles
precision problems directly. If a precision problem occurs, Qhull
merges one of the offending facets into one of its neighbors.
With multiple merges, topological problems may lead to severe precision
problems, or prevent Qhull from continuing.  Otherwise, Qhull will either
fix the problem or attempt to merge the last remaining 