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.math3.linear; 019 020/** 021 * Interface defining a visitor for matrix entries. 022 * 023 * @see DefaultRealMatrixChangingVisitor 024 * @since 2.0 025 */ 026public interface RealMatrixChangingVisitor { 027 /** 028 * Start visiting a matrix. 029 * <p>This method is called once before any entry of the matrix is visited.</p> 030 * @param rows number of rows of the matrix 031 * @param columns number of columns of the matrix 032 * @param startRow Initial row index 033 * @param endRow Final row index (inclusive) 034 * @param startColumn Initial column index 035 * @param endColumn Final column index (inclusive) 036 */ 037 void start(int rows, int columns, 038 int startRow, int endRow, int startColumn, int endColumn); 039 040 /** 041 * Visit one matrix entry. 042 * @param row row index of the entry 043 * @param column column index of the entry 044 * @param value current value of the entry 045 * @return the new value to be set for the entry 046 */ 047 double visit(int row, int column, double value); 048 049 /** 050 * End visiting a matrix. 051 * <p>This method is called once after all entries of the matrix have been visited.</p> 052 * @return the value that the <code>walkInXxxOrder</code> must return 053 */ 054 double end(); 055}