/*
* 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.substitutions.n;
import cc.redberry.core.tensor.*;
import cc.redberry.core.indexmapping.IndexMappingBuffer;
import cc.redberry.core.indexmapping.IndexMappingImpl;
import cc.redberry.core.indexmapping.IndexMappingUtils;
import cc.redberry.core.indexmapping.IndexMappings;
import cc.redberry.core.tensor.iterators.TraverseState;
import cc.redberry.core.transformations.ApplyIndexMappingTransformation;
import cc.redberry.transformation.Transformation;
import cc.redberry.transformation.substitutions.ApplyIndexMappingUtils;
import cc.redberry.core.utils.TensorUtils;
/**
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
*/
class SimpleSubstitution implements Transformation {
static final SubstitutionProvider SIMPLE_SUBSTITUTION_PROVIDER = new SubstitutionProvider() {
@Override
public SimpleSubstitution createSubstitution(Tensor from, Tensor to, boolean allowDiffStates) {
return new SimpleSubstitution(from, to, allowDiffStates);
}
};
private final Tensor from, to;
private final boolean allowDiffStates;
private SimpleSubstitution(Tensor from, Tensor to, boolean allowDiffStates) {
this.from = from;
this.to = to;
this.allowDiffStates = allowDiffStates;
}
@Override
public Tensor transform(Tensor tensor) {
Tensor parent = tensor.getParent();
TensorWrapper tensorWrapper = new TensorWrapper(tensor);
TreeIteratorSubs iterator = new TreeIteratorSubs(tensorWrapper);
Tensor current;
TraverseState state;
int i;
OUT:
while ((state = iterator.next()) != null) {
if (state != TraverseState.Entering)
continue;
current = iterator.tensor();
IndexMappingBuffer buffer =
IndexMappingUtils.tryGetPositiveWithoutDiffStates(IndexMappings.createPort(from, current, allowDiffStates));
if (buffer == null)
continue;
for (Derivative derivative : iterator.derivativeStack)
for (i = 0; i < derivative.getDerivativeOrder(); ++i)
if (IndexMappings.mappingExists(from, derivative.getVariation(i), true) //TODO Simple tensor optimization
|| TensorUtils.contains(to, derivative.getVariation(i)))
throw new InconsistentSubstitutionException("TODO message");
Tensor newTo = to.clone();
if (!allowDiffStates || !IndexMappingUtils.containsDiffStates(buffer))
newTo = ApplyIndexMappingTransformation.INSTANCE.perform(newTo, new IndexMappingImpl(iterator.usedIndices(), buffer));
else
newTo = ApplyIndexMappingUtils.applyIndexMappingWithDiffStates(newTo, buffer, iterator.usedIndices());
if (buffer.getSignum() == true)
newTo = new Product(TensorNumber.createMINUSONE(), newTo);
iterator.set(newTo);
}
Tensor result = tensorWrapper.getInnerTensor();
result.setParent(parent);
return result;
}
}