R interface to (some of) cddlib (<http://www.ifor.math.ethz.ch/~fukuda/cdd_home/cdd.html>). Converts back and forth between two representations of a convex polytope: as solution of a set of linear equalities and inequalities and as convex hull of set of points and rays. Also does linear programming and redundant generator elimination (for example, convex hull in n dimensions). All functions can use exact infinite-precision rational arithmetic.
