/*
* Redberry: symbolic tensor computations.
*
* Copyright (c) 2010-2013:
* Stanislav Poslavsky <stvlpos@mail.ru>
* Bolotin Dmitriy <bolotin.dmitriy@gmail.com>
*
* This file is part of Redberry.
*
* Redberry is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Redberry is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Redberry. If not, see <http://www.gnu.org/licenses/>.
*/
package cc.redberry.core.groups.permutations;
import cc.redberry.core.transformations.factor.jasfactor.edu.jas.arith.BigInteger;
/**
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
*/
public final class PermutationGroup {
/**
* Strong generating set
*/
final SGSElement[] sgs;
public PermutationGroup(Permutation[] generators) {
this.sgs = SchreierSimsAlgorithm.createSGS(generators);
}
public boolean isMember(Permutation permutation) {
Permutation temp = permutation;
int i, beta;
for (i = 0; i < sgs.length; ++i) {
beta = temp.newIndexOf(sgs[i].basePoint);
if (!sgs[i].belongsToOrbit(beta))
return false;
temp = temp.composition(sgs[i].getInverseTransversalOf(beta));
}
return temp.isIdentity();
}
public BigInteger getOrder() {
BigInteger order = BigInteger.ONE;
for (SGSElement element : sgs)
order = order.multiply(BigInteger.valueOf(element.getOrbitSize()));
return order;
}
public SGSElement[] getStrongGeneratingSet() {
return sgs;
}
}