Home Online Manual
Top
Back: makePDivisor
Forward: pdivisorplus
FastBack:
FastForward:
Up: divisors_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.15.8.18 evaluatePDivisor

Procedure from library divisors.lib (see divisors_lib).

Usage:
evaluatePDivisor(D,v); D = pdivisor, v = intvec.

Assume:
D is a polyhedral divisor on X and v is a point in the dual of the tailcone of the coefficients.

Return:
a formal divisor on X

Theory:
Will evaluate the polyhedral sum to an integer formal sum.

Example:
 
LIB "divisors.lib";
LIB("polymake.so");
==> Welcome to polymake version
==> Copyright (c) 1997-2015
==> Ewgenij Gawrilow, Michael Joswig (TU Darmstadt)
==> http://www.polymake.org
ring r=31991,(x,y,z),dp;
ideal I = y^2*z - x*(x-z)*(x+3*z);
qring Q = std(I);
divisor A = makeDivisor(ideal(x,z),ideal(1));
divisor B = makeDivisor(ideal(x,y),ideal(1));
intmat M[4][4]= 1,4,0,0,
1,0,3,0,
0,0,0,2,
1,1,1,1;
polytope PP = polytopeViaPoints(M);
pdivisor pD = makePDivisor(list(list(PP,A),list(PP,B)));
intvec v=1,1,1;
evaluatePDivisor(pD,v);
==> polymake: used package cdd
==>   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 ppl
==>   The Parma Polyhedra Library (PPL): A C++ library for convex polyhedra
==>   and other numerical abstractions.
==>   http://www.cs.unipr.it/ppl/
==> 
==> 3*( (z,x) - (1) )
==> +3*( (y,x) - (1) )
==>