From b28e9802dc55a004cc5b7ebb127273f3d856a3ad Mon Sep 17 00:00:00 2001 From: Jonathan Kliem Date: Mon, 11 May 2020 16:00:03 +0200 Subject: [PATCH] documentated that backend field is fast --- src/sage/geometry/polyhedron/library.py | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/sage/geometry/polyhedron/library.py b/src/sage/geometry/polyhedron/library.py index fa453f71f55..f3eca11f157 100644 --- a/src/sage/geometry/polyhedron/library.py +++ b/src/sage/geometry/polyhedron/library.py @@ -2520,6 +2520,15 @@ def permutahedron(self, n, project=False, backend=None): sage: perm4.graph().is_isomorphic(graphs.BubbleSortGraph(4)) True + As both Hrepresentation an Vrepresentation are known, the permutahedron can be set + up with both using the backend ``field``. The following takes very very long time + to recompute, e.g. with backend ``ppl``:: + + sage: polytopes.permutahedron(8, backend='field') # (~1s) + A 7-dimensional polyhedron in QQ^8 defined as the convex hull of 40320 vertices + sage: polytopes.permutahedron(9, backend='field') # long time -- (~5s) + A 8-dimensional polyhedron in QQ^9 defined as the convex hull of 362880 vertices + .. SEEALSO:: * :meth:`~sage.graphs.graph_generators.GraphGenerators.BubbleSortGraph`