/*
* Copyright 2011-2014, by Vladimir Kostyukov and Contributors.
*
* This file is part of la4j project (http://la4j.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Contributor(s): -
*
*/
package org.la4j.operation.ooplace;
import org.la4j.operation.SymmetricVectorVectorOperation;
import org.la4j.Vector;
import org.la4j.iterator.VectorIterator;
import org.la4j.Vectors;
import org.la4j.vector.DenseVector;
import org.la4j.vector.functor.VectorFunction;
import org.la4j.vector.SparseVector;
public class OoPlaceInnerProduct extends SymmetricVectorVectorOperation<Double> {
@Override
public Double apply(final SparseVector a, final SparseVector b) {
VectorIterator these = a.nonZeroIterator();
VectorIterator those = b.nonZeroIterator();
return these.innerProduct(those);
}
@Override
public Double applySymmetric(DenseVector a, SparseVector b) {
return b.foldNonZero(Vectors.asSumFunctionAccumulator(0.0, dot(a)));
}
@Override
public Double apply(final DenseVector a, final DenseVector b) {
double result = 0.0;
for (int i = 0; i < a.length(); i++) {
result += a.get(i) * b.get(i);
}
return result;
}
private VectorFunction dot(final Vector b) {
return new VectorFunction() {
@Override
public double evaluate(int i, double value) {
return b.get(i) * value;
}
};
}
@Override
public void ensureApplicableTo(Vector a, Vector b) {
if (a.length() != b.length()) {
throw new IllegalArgumentException(
"Given vectors should have the same length: " +
a.length() + " does not equal to " + b.length() + "."
);
}
}
}