/*
* 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 java.util.ArrayList;
import java.util.List;
import cc.redberry.core.indices.Indices;
import cc.redberry.core.indices.IndicesUtils;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.TensorField;
import cc.redberry.core.tensor.TensorWrapper;
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.Transformations;
import cc.redberry.transformation.substitutions.ApplyIndexMappingUtils;
/**
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
*/
class TensorFieldSubstitution implements Transformation {
final static SubstitutionProvider TENSOR_FIELD_PROVIDER = new SubstitutionProvider() {
@Override
public Transformation createSubstitution(Tensor from, Tensor to, boolean allowDiffStates) {
return new TensorFieldSubstitution((TensorField) from, to, allowDiffStates);
}
};
private final TensorField from;
private final Tensor to;
private boolean allowDiffStates;
private TensorFieldSubstitution(TensorField 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);
TraverseState state;
Tensor current;
OUT:
while ((state = iterator.next()) != null) {
if (state != TraverseState.Entering)
continue;
current = iterator.tensor();
if (!(current instanceof TensorField))
continue;
TensorField currentField = (TensorField) current;
IndexMappingBuffer buffer =
IndexMappingUtils.tryGetPositiveWithoutDiffStates(IndexMappings.createPortForSimpleTensor(from, currentField, allowDiffStates));
if (buffer == null)
continue;
assert from.getArgs().length == currentField.getArgs().length;
Tensor[] fromArgs = from.getArgs(), currentArgs = currentField.getArgs();
Indices[] fromIndices = from.getArgIndices(), currentIndices = currentField.getArgIndices();
List<Transformation> transformations = new ArrayList<>();
Tensor fArg;
int[] cIndices, fIndices;
int i, j;
for (i = 0; i < fromArgs.length; ++i) {
if (IndexMappings.mappingExists(currentArgs[i], fromArgs[i], allowDiffStates))
continue;
fArg = fromArgs[i].clone();
fIndices = fromIndices[i].getAllIndices().copy();
cIndices = currentIndices[i].getAllIndices().copy();
if (cIndices.length != fIndices.length)
throw new InconsistentSubstitutionException(from, to, current);
boolean diffStates = false;
for (j = 0; j < cIndices.length; ++j)
if (IndicesUtils.getRawStateInt(cIndices[j]) != IndicesUtils.getRawStateInt(fIndices[j])) {
diffStates = true;
break;
}
if (diffStates && !allowDiffStates)
continue OUT;
if (diffStates) {
fArg = ApplyIndexMappingUtils.applyIndexMappingWithDiffStates(fArg, fIndices, cIndices, new int[0]);
fArg = Transformations.contractMetrics(fArg);
fromArgs[i] = Transformations.contractMetrics(fromArgs[i]);
} else {
for (j = 0; j < cIndices.length; ++j) {
cIndices[j] = IndicesUtils.getNameWithType(cIndices[j]);
fIndices[j] = IndicesUtils.getNameWithType(fIndices[j]);
}
IndexMappingImpl im = new IndexMappingImpl(new int[0], fIndices, cIndices);
fArg = ApplyIndexMappingTransformation.INSTANCE.perform(fArg, im);
}
if (!IndexMappings.mappingExists(fromArgs[i], fArg, allowDiffStates))
throw new InconsistentSubstitutionException(from, to, current);
transformations.add(Substitutions.createSubstitution(fArg, currentArgs[i], allowDiffStates));
}
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 (!transformations.isEmpty()) {
for (Transformation transformation : transformations)
newTo = transformation.transform(newTo);
int[] indices = newTo.getIndices().getFreeIndices().getAllIndices().copy();
for (i = 0; i < indices.length; ++i)
indices[i] = IndicesUtils.getNameWithType(indices[i]);
newTo = ApplyIndexMappingTransformation.INSTANCE.perform(newTo, new IndexMappingImpl(iterator.usedIndices(), indices, indices));
}
iterator.set(newTo);
}
Tensor result = tensorWrapper.getInnerTensor();
result.setParent(parent);
return result;
}
private static class DummyTransformation implements Transformation {
static final DummyTransformation INSTANCE = new DummyTransformation();
private DummyTransformation() {
}
@Override
public Tensor transform(Tensor tensor) {
return tensor;
}
}
}