/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.mahout.math.decomposer;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.VectorIterable;
public class SimpleEigenVerifier implements SingularVectorVerifier {
@Override
public EigenStatus verify(VectorIterable corpus, Vector vector) {
Vector resultantVector = corpus.timesSquared(vector);
double newNorm = resultantVector.norm(2);
double oldNorm = vector.norm(2);
double eigenValue;
double cosAngle;
if (newNorm > 0 && oldNorm > 0) {
eigenValue = newNorm / oldNorm;
cosAngle = resultantVector.dot(vector) / newNorm * oldNorm;
} else {
eigenValue = 1.0;
cosAngle = 0.0;
}
return new EigenStatus(eigenValue, cosAngle, false);
}
}