/*
 * 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
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package org.apache.commons.math3.linear;

This interface defines a visitor for the entries of a vector. Visitors
implementing this interface may alter the entries of the vector being
visited.
Since:
3.1/**
 * This interface defines a visitor for the entries of a vector. Visitors
 * implementing this interface may alter the entries of the vector being
 * visited.
 *
 * @since 3.1
 */
public interface RealVectorChangingVisitor {
    
Start visiting a vector. This method is called once, before any entry
of the vector is visited.
Params:
dimension – the size of the vector
start – the index of the first entry to be visited
end – the index of the last entry to be visited (inclusive)/**
     * Start visiting a vector. This method is called once, before any entry
     * of the vector is visited.
     *
     * @param dimension the size of the vector
     * @param start the index of the first entry to be visited
     * @param end the index of the last entry to be visited (inclusive)
     */
    void start(int dimension, int start, int end);

    
Visit one entry of the vector.
Params:
index – the index of the entry being visited
value – the value of the entry being visited
Returns:
the new value of the entry being visited/**
     * Visit one entry of the vector.
     *
     * @param index the index of the entry being visited
     * @param value the value of the entry being visited
     * @return the new value of the entry being visited
     */
    double visit(int index, double value);

    
End visiting a vector. This method is called once, after all entries of
the vector have been visited.
Returns:
the value returned by RealVector.walkInDefaultOrder(RealVectorChangingVisitor), RealVector.walkInDefaultOrder(RealVectorChangingVisitor, int, int), RealVector.walkInOptimizedOrder(RealVectorChangingVisitor) or RealVector.walkInOptimizedOrder(RealVectorChangingVisitor, int, int)/**
     * End visiting a vector. This method is called once, after all entries of
     * the vector have been visited.
     *
     * @return the value returned by
     * {@link RealVector#walkInDefaultOrder(RealVectorChangingVisitor)},
     * {@link RealVector#walkInDefaultOrder(RealVectorChangingVisitor, int, int)},
     * {@link RealVector#walkInOptimizedOrder(RealVectorChangingVisitor)}
     * or
     * {@link RealVector#walkInOptimizedOrder(RealVectorChangingVisitor, int, int)}
     */
    double end();
}