Top
Back: GITfanFromOrbitCones
Forward: GKZfan
FastBack:
FastForward:
Up: gitfan_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.13.3.9 GITfanParallel

Procedure from library gitfan.lib (see gitfan_lib).

Usage:
GITfanParallel(OC, Q, Qgamma [, file1]); OC:list, Q:intmat, Qgamma:cone, file1:string

Purpose:
Returns the common refinement of the cones given in
the list OC which is supposed to contain the orbit cones intersected with Qgamma. The optional argument can be used to specify a name for a file which will contain the hashes of the GIT-cones. To obtain the whole GIT-fan Qgamma has to be take the cone generated by the columns of Q.

Return:
a list containing the bigint hashes of the GIT cones.

Note:
The procedure uses parallel computation for the construction of the GIT-cones.

Example:
 
LIB "gitfan.lib";
setcores(4);
==> 4
ring R = 0,T(1..10),wp(1,1,1,1,1,1,1,1,1,1);
ideal J =
T(5)*T(10)-T(6)*T(9)+T(7)*T(8),
T(1)*T(9)-T(2)*T(7)+T(4)*T(5),
T(1)*T(8)-T(2)*T(6)+T(3)*T(5),
T(1)*T(10)-T(3)*T(7)+T(4)*T(6),
T(2)*T(10)-T(3)*T(9)+T(4)*T(8);
intmat Q[5][10] =
1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 1, 1, 1, 0, 0, 0,
0, 1, 1, 0, 0, 0, -1, 1, 0, 0,
0, 1, 0, 1, 0, -1, 0, 0, 1, 0,
0, 0, 1, 1, -1, 0, 0, 0, 0, 1;
list AF= afaces(J);
print(size(AF));
==> 172
list OC = orbitCones(AF,Q);
cone Qgamma = coneViaPoints(transpose(Q));
list GIT = GITfanParallel(OC,Q,Qgamma);
size(GIT);
==> 76


Top Back: GITfanFromOrbitCones Forward: GKZfan FastBack: FastForward: Up: gitfan_lib Top: Singular Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 4.3.2, 2023, generated by texi2html.