/*
* 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.collect;
import cc.redberry.concurrent.OutputPortUnsafe;
import cc.redberry.core.context.CC;
import cc.redberry.core.indexmapping.IndexMappingBuffer;
import cc.redberry.core.indexmapping.IndexMappingBufferTester;
import cc.redberry.core.indexmapping.IndexMappings;
import cc.redberry.core.indices.IndicesUtils;
import cc.redberry.core.tensor.Product;
import cc.redberry.core.tensor.Sum;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.TensorNumber;
import cc.redberry.core.tensor.testing.TTest;
import cc.redberry.transformation.Transformations;
/**
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
*/
public class EqualsSplit extends Split<EqualsSplit> {
private final Tensor factoredOut;
private final Sum factors = new Sum();
public EqualsSplit(Tensor factoredOut, Tensor term) {
this.factoredOut = factoredOut.clone();
this.term = term;
factors.add(factoredOut);
}
// @Override
// public boolean canMerge(EqualsSplit split) {
// return TTest.testParity(term, split.term);
// }
@Override
public boolean mergeFrom(EqualsSplit split) {
int[] fromIndices = term.getIndices().getFreeIndices().getAllIndices().copy();
for (int i = 0; i < fromIndices.length; ++i)
fromIndices[i] = IndicesUtils.getNameWithType(fromIndices[i]);
OutputPortUnsafe<IndexMappingBuffer> provider = IndexMappings.createPort(new IndexMappingBufferTester(fromIndices, CC.withMetric()), term, split.term);
IndexMappingBuffer buffer;
boolean sign = false;
if ((buffer = provider.take()) != null) {
buffer.removeContracted();
assert buffer.isEmpty();
sign = buffer.getSignum();
}
if (buffer == null)
return false;
factors.add(sign == false ? split.factoredOut : new Product(TensorNumber.createMINUSONE(), split.factoredOut));
return true;
}
@Override
public Tensor tensorEquvivalent() {
// if (term instanceof TensorNumber)
// return factors.equivalent();
// if (factoredOut instanceof TensorNumber && ((TensorNumber) factoredOut).isOne())
// return term.equivalent();
// return new Product(Transformations.calculateNumbers(factors), term);
return pairProduct(Transformations.calculateNumbers(factors), term);
}
}