Singular Manual: gorensteinIndex

  | #### D.16.2.7 gorensteinIndex `Syntax:` `Polymake::gorensteinIndex(` polytope p `)` `Assume:` p is Gorenstein, i.e. n*p+v is reflexive for some dilatation n and translation v. `Type:` int `Purpose:` returns a factor n such that n*p+v is reflexive for some translation v. `Note:` you can check whether p is Gorenstein by Polymake::isGorenstein(p); the translation v can be computed via Polymake::gorensteinVector(p). `Example:`
        LIB"polymake.lib";
      ==> Welcome to polymake
      ==> Copyright (c) 1997-2012
      ==> Ewgenij Gawrilow, Michael Joswig (TU Darmstadt)
      ==> http://www.polymake.org
        intmat M[4][3]=1,1,0, 1,0,1, 1,0,0, 1,1,1;
        polytope p = polytopeViaPoints(M);
        Polymake::gorensteinIndex(p);
      ==> polymake: used package cddlib
      ==>   Implementation of the double description method of Motzkin et al.
      ==>   Copyright by Komei Fukuda.
      ==>   http://www.ifor.math.ethz.ch/~fukuda/cdd_home/cdd.html
      ==>
      ==> polymake: used package lrslib
      ==>   Implementation of the reverse search algorithm of Avis and Fukuda.
      ==>   Copyright by David Avis.
      ==>   http://cgm.cs.mcgill.ca/~avis/lrs.html
      ==>
      ==> 2
        intmat N[3][3]=1,2,0, 1,0,2, 1,-2,-2;
        polytope q = polytopeViaPoints(N);
        Polymake::gorensteinIndex(q);
      ==>    ? gorensteinIndex: input polytope not gorenstein
      ==>    ? error occurred in or before ./examples/gorensteinIndex.sing line 7: \
         `  Polymake::gorensteinIndex(q);`

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