cc.redberry.transformation.substitutions.NaiveSubstitution Maven / Gradle / Ivy

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/*
 * Redberry: symbolic tensor computations.
 *
 * Copyright (c) 2010-2012:
 *   Stanislav Poslavsky   
 *   Bolotin Dmitriy       
 *
 * 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 .
 */
package cc.redberry.transformation.substitutions;

import cc.redberry.core.tensor.Expression;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.indexmapping.IndexMappingImpl;
import cc.redberry.core.indexmapping.IndexMappingBuffer;
import cc.redberry.core.indexmapping.IndexMappings;
import cc.redberry.transformation.Transformation;
import cc.redberry.transformation.Transformer;

/**
 *
 * @author Dmitry Bolotin
 * @author Stanislav Poslavsky
 */
public class NaiveSubstitution extends AbstractSubstitution {
    private NaiveSubstitution(Expression expr) {
        super(expr.left(), expr.right(), false);
    }
    
    private NaiveSubstitution(Tensor from, Tensor to) {
        super(from, to, false);
    }
    
    @Override
    protected Class getFromClasss() {
        return from.getClass();
    }
    
    @Override
    public Tensor transform(Tensor tensor) {
        IndexMappingBuffer im = IndexMappings.getFirst(from, tensor, false);
        if (im == null)
            return tensor;
        Tensor newTo = to.clone();
        (new IndexMappingImpl(new int[0],im)).apply(newTo);
        return newTo;
    }
    
    public static Transformation create(Expression expr) {
        return new Transformer(new NaiveSubstitution(expr));
    }
}