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 */
017package org.apache.commons.math4.linear;
018
019/**
020 * Marker class for RealVectors that require sparse backing storage
021 * <p>
022 *  Caveat: Implementation are allowed to assume that, for any {@code x},
023 *  the equality {@code x * 0d == 0d} holds. But it is is not true for
024 *  {@code NaN}. Moreover, zero entries will lose their sign.
025 *  Some operations (that involve {@code NaN} and/or infinities) may
026 *  thus give incorrect results, like multiplications, divisions or
027 *  functions mapping.
028 * </p>
029 * @since 2.0
030 */
031public abstract class SparseRealVector extends RealVector {}