/*
* Redberry: symbolic tensor computations.
*
* Copyright (c) 2010-2012:
* 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.transformation.fraction;
import java.util.ArrayList;
import java.util.List;
import cc.redberry.core.tensor.Fraction;
import cc.redberry.core.tensor.Product;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.TensorIterator;
import cc.redberry.transformation.Transformation;
/**
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
* @author Konstantin Kiselev
*/
public class ReduceFraction implements Transformation {
@Override
public Tensor transform(Tensor tensor) {
if (!(tensor instanceof Fraction))
return tensor;
Fraction fraction = (Fraction) tensor;
TensorIterator iterator = fraction.iterator();
Tensor current;
while (iterator.hasNext()) {
current = iterator.next();
if (current instanceof Fraction) {
Fraction temp = (Fraction) current;
if (Fraction.onDenominatorIndicator.is(iterator))
return new Fraction(new Product(fraction.getNumerator(), temp.getDenominator()), temp.getNumerator());
else
return new Fraction(temp.getNumerator(), new Product(fraction.getDenominator(), temp.getDenominator()));
}
if (current instanceof Product) {
List<Tensor> multiplicands = new ArrayList<>();
TensorIterator it = current.iterator();
Tensor current1;
while (it.hasNext()) {
current1 = it.next();
if (current1 instanceof Fraction) {
Fraction currentFraction = (Fraction) current1;
multiplicands.add(currentFraction.getDenominator());
it.set(currentFraction.getNumerator());
}
}
if (multiplicands.isEmpty())
return tensor;
Product newNumerator = new Product();
if (Fraction.onDenominatorIndicator.is(iterator)) {
newNumerator.add(fraction.getNumerator());
newNumerator.add(multiplicands);
return new Fraction(newNumerator, fraction.getDenominator());
} else {
newNumerator.add(fraction.getDenominator());
newNumerator.add(multiplicands);
return new Fraction(fraction.getNumerator(), newNumerator);
}
}
}
return tensor;
}
}