GFAN(1) User Commands GFAN(1)NAME
Gfan - program for computing with Groebner fans
DESCRIPTION
This is a program for computing all reduced Groebner bases of a polynomial ideal. It takes a generating set for the ideal as input. By
default the enumeration is done by an almost memoryless reverse search. If the ideal is symmetric the symmetry option is useful and enumer-
ation will be done up to symmetry using a breadth first search. The program needs a starting Groebner basis to do its computations. If the
-g option is not specified it will compute one using Buchberger's algorithm.
Usage:
/usr/bin/gfan [options]
Options:
-g Tells the program that the input is already a Groebner basis (with the initial term of each polynomial being the first ones listed).
Use this option if it takes too much time to compute the starting (standard degree lexicographic) Groebner basis and the input is
already a Groebner basis.
--symmetry
Tells the program to read in generators for a group of symmetries (subgroup of $S_n$) after having read in the ideal. The program
checks that the ideal stays fixed when permuting the variables with respect to elements in the group. The program uses breadth first
search to compute the set of reduced Groebner bases up to symmetry with respect to the specified subgroup.
-e Echo. Output the generators for the symmetry group.
--subspace
Only do breadth first search on cones with their interior intersecting a specified subspace. The subspace is given by a list of
hyperplane normals at the end of the input. The intersection of the hyperplanes is the subspace being specified. Note that the set
of Groebner cones intersecting the subspace could be disconnected and that only one connected component is computed. Works only
together with --symmetry.
--disableSymmetryTest
When using --symmetry this option will disable the check that the group read off from the input actually is a symmetry group with
respect to the input ideal.
Gfan Groebner fan package Version 0.3 May 2008 GFAN(1)
Check Out this Related Man Page
INSTANCEFACE(3) MBK PHYSICAL UTILITY FUNCTIONS INSTANCEFACE(3)NAME
instanceface - returns the face of a connector in a placed instance
ORIGIN
This software belongs to the ALLIANCE CAD SYSTEM developed by the ASIM team at LIP6 laboratory of Universite Pierre et Marie CURIE, in
Paris, France.
Web : http://asim.lip6.fr/recherche/alliance/
E-mail : alliance-users@asim.lip6.fr
SYNOPSYS
#include "mph403.h"
void *instanceface(modelface, symmetry)
char modelface, symmetry;
PARAMETERS
modelface Face of a connector in its figure.
symmetry Geometrical operation applied to the instanciation of the figure.
DESCRIPTION
instanceface determines the orientation of a connector in an instance of its model.
EXAMPLE
#include "mph403.h"
char channelFace(channelDir, i, c)
char channelDir;
phins_list *i;
phcon_list *c;
{
if (channelDir == VER)
switch (instanceface(c->ORIENT, i->TRANSF)) {
case EAST :
return WEST;
case WEST :
return EAST;
default :
return instanceface(c->ORIENT, i->TRANSF);
}
else
switch (instanceface(c->ORIENT, i->TRANSF)) {
case NORTH :
return SOUTH;
case SOUTH :
return NORTH;
default :
return instanceface(c->ORIENT, i->TRANSF);
}
}
SEE ALSO mbk(1), phcon(3), phfig(3), phins(3).
BUG REPORT
This tool is under development at the ASIM department of the LIP6 laboratory.
We need your feedback to improve documentation and tools.
ASIM /LIP6 October 1, 1997 INSTANCEFACE(3)