1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.math4.legacy.linear;
19
20 /**
21 * Interface defining a visitor for matrix entries.
22 *
23 * @see DefaultRealMatrixChangingVisitor
24 * @since 2.0
25 */
26 public interface RealMatrixChangingVisitor {
27 /**
28 * Start visiting a matrix.
29 * <p>This method is called once before any entry of the matrix is visited.</p>
30 * @param rows number of rows of the matrix
31 * @param columns number of columns of the matrix
32 * @param startRow Initial row index
33 * @param endRow Final row index (inclusive)
34 * @param startColumn Initial column index
35 * @param endColumn Final column index (inclusive)
36 */
37 void start(int rows, int columns,
38 int startRow, int endRow, int startColumn, int endColumn);
39
40 /**
41 * Visit one matrix entry.
42 * @param row row index of the entry
43 * @param column column index of the entry
44 * @param value current value of the entry
45 * @return the new value to be set for the entry
46 */
47 double visit(int row, int column, double value);
48
49 /**
50 * End visiting a matrix.
51 * <p>This method is called once after all entries of the matrix have been visited.</p>
52 * @return the value that the <code>walkInXxxOrder</code> must return
53 */
54 double end();
55 }