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
018 package org.apache.commons.math3.linear;
019
020 import org.apache.commons.math3.FieldElement;
021
022 /**
023 * Interface defining a visitor for matrix entries.
024 *
025 * @param <T> the type of the field elements
026 * @version $Id: FieldMatrixChangingVisitor.java 1416643 2012-12-03 19:37:14Z tn $
027 * @since 2.0
028 */
029 public interface FieldMatrixChangingVisitor<T extends FieldElement<?>> {
030 /**
031 * Start visiting a matrix.
032 * <p>This method is called once before any entry of the matrix is visited.</p>
033 * @param rows number of rows of the matrix
034 * @param columns number of columns of the matrix
035 * @param startRow Initial row index
036 * @param endRow Final row index (inclusive)
037 * @param startColumn Initial column index
038 * @param endColumn Final column index (inclusive)
039 */
040 void start(int rows, int columns,
041 int startRow, int endRow, int startColumn, int endColumn);
042
043 /**
044 * Visit one matrix entry.
045 * @param row row index of the entry
046 * @param column column index of the entry
047 * @param value current value of the entry
048 * @return the new value to be set for the entry
049 */
050 T visit(int row, int column, T value);
051
052 /**
053 * End visiting a matrix.
054 * <p>This method is called once after all entries of the matrix have been visited.</p>
055 * @return the value that the <code>walkInXxxOrder</code> must return
056 */
057 T end();
058 }