001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.math4.linear;
019
020import org.apache.commons.math4.exception.MathIllegalArgumentException;
021import org.apache.commons.math4.exception.util.LocalizedFormats;
022
023/**
024 * Exception to be thrown when a self-adjoint {@link RealLinearOperator}
025 * is expected.
026 * Since the coefficients of the matrix are not accessible, the most
027 * general definition is used to check that A is not self-adjoint, i.e.
028 * there exist x and y such as {@code | x' A y - y' A x | >= eps},
029 * where {@code eps} is a user-specified tolerance, and {@code x'}
030 * denotes the transpose of {@code x}.
031 * In the terminology of this exception, {@code A} is the "offending"
032 * linear operator, {@code x} and {@code y} are the first and second
033 * "offending" vectors, respectively.
034 *
035 * @since 3.0
036 */
037public class NonSelfAdjointOperatorException
038    extends MathIllegalArgumentException {
039    /** Serializable version Id. */
040    private static final long serialVersionUID = 1784999305030258247L;
041
042    /** Creates a new instance of this class. */
043    public NonSelfAdjointOperatorException() {
044        super(LocalizedFormats.NON_SELF_ADJOINT_OPERATOR);
045    }
046}