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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    *      https://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  /*
19   * This is not the original file distributed by the Apache Software Foundation
20   * It has been modified by the Hipparchus project
21   */
22  package org.hipparchus.optim.linear;
23  
24  import org.hipparchus.optim.OptimizationData;
25  import org.hipparchus.optim.PointValuePair;
26  
27  /**
28   * A callback object that can be provided to a linear optimizer to keep track
29   * of the best solution found.
30   *
31   */
32  public class SolutionCallback implements OptimizationData {
33      /** The SimplexTableau used by the SimplexSolver. */
34      private SimplexTableau tableau;
35  
36      /** Empty constructor.
37       * <p>
38       * This constructor is not strictly necessary, but it prevents spurious
39       * javadoc warnings with JDK 18 and later.
40       * </p>
41       * @since 3.0
42       */
43      public SolutionCallback() { // NOPMD - unnecessary constructor added intentionally to make javadoc happy
44          // nothing to do
45      }
46  
47      /**
48       * Set the simplex tableau used during the optimization once a feasible
49       * solution has been found.
50       *
51       * @param tableau the simplex tableau containing a feasible solution
52       */
53      void setTableau(final SimplexTableau tableau) {
54          this.tableau = tableau;
55      }
56  
57      /**
58       * Retrieve the best solution found so far.
59       * <p>
60       * <b>Note:</b> the returned solution may not be optimal, e.g. in case
61       * the optimizer did reach the iteration limits.
62       *
63       * @return the best solution found so far by the optimizer, or {@code null} if
64       * no feasible solution could be found
65       */
66      public PointValuePair getSolution() {
67          return tableau != null ? tableau.getSolution() : null;
68      }
69  
70      /**
71       * Returns if the found solution is optimal.
72       * @return {@code true} if the solution is optimal, {@code false} otherwise
73       */
74      public boolean isSolutionOptimal() {
75          return tableau != null && tableau.isOptimal();
76      }
77  }