/*
    * 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
    *
    *      https://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
   * limitations under the License.
   */
  
  /*
   * This is not the original file distributed by the Apache Software Foundation
   * It has been modified by the Hipparchus project
   */
  package org.hipparchus.optim.linear;
  
  import org.hipparchus.UnitTestUtils;
  import org.hipparchus.optim.nonlinear.scalar.GoalType;
  import org.junit.jupiter.api.Test;
  
  import java.util.ArrayList;
  import java.util.Collection;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  class SimplexTableauTest {
  
      @Test
      void testInitialization() {
          LinearObjectiveFunction f = createFunction();
          Collection<LinearConstraint> constraints = createConstraints();
          SimplexTableau tableau =
              new SimplexTableau(f, constraints, GoalType.MAXIMIZE, false, 1.0e-6);
          double[][] expectedInitialTableau = {
                                               {-1, 0,  -1,  -1,  2, 0, 0, 0, -4},
                                               { 0, 1, -15, -10, 25, 0, 0, 0,  0},
                                               { 0, 0,   1,   0, -1, 1, 0, 0,  2},
                                               { 0, 0,   0,   1, -1, 0, 1, 0,  3},
                                               { 0, 0,   1,   1, -2, 0, 0, 1,  4}
          };
          customAssertMatrixEquals(expectedInitialTableau, tableau.getData());
      }
  
      @Test
      void testDropPhase1Objective() {
          LinearObjectiveFunction f = createFunction();
          Collection<LinearConstraint> constraints = createConstraints();
          SimplexTableau tableau =
              new SimplexTableau(f, constraints, GoalType.MAXIMIZE, false, 1.0e-6);
          double[][] expectedTableau = {
                                        { 1, -15, -10, 0, 0, 0, 0},
                                        { 0,   1,   0, 1, 0, 0, 2},
                                        { 0,   0,   1, 0, 1, 0, 3},
                                        { 0,   1,   1, 0, 0, 1, 4}
          };
          tableau.dropPhase1Objective();
          customAssertMatrixEquals(expectedTableau, tableau.getData());
      }
  
      @Test
      void testTableauWithNoArtificialVars() {
          LinearObjectiveFunction f = new LinearObjectiveFunction(new double[] {15, 10}, 0);
          Collection<LinearConstraint> constraints = new ArrayList<LinearConstraint>();
          constraints.add(new LinearConstraint(new double[] {1, 0}, Relationship.LEQ, 2));
          constraints.add(new LinearConstraint(new double[] {0, 1}, Relationship.LEQ, 3));
          constraints.add(new LinearConstraint(new double[] {1, 1}, Relationship.LEQ, 4));
          SimplexTableau tableau =
              new SimplexTableau(f, constraints, GoalType.MAXIMIZE, false, 1.0e-6);
          double[][] initialTableau = {
                                       {1, -15, -10, 25, 0, 0, 0, 0},
                                       {0,   1,   0, -1, 1, 0, 0, 2},
                                       {0,   0,   1, -1, 0, 1, 0, 3},
                                       {0,   1,   1, -2, 0, 0, 1, 4}
          };
          customAssertMatrixEquals(initialTableau, tableau.getData());
      }
  
      @Test
      void testSerial() {
          LinearObjectiveFunction f = createFunction();
          Collection<LinearConstraint> constraints = createConstraints();
          SimplexTableau tableau =
              new SimplexTableau(f, constraints, GoalType.MAXIMIZE, false, 1.0e-6);
          assertEquals(tableau, UnitTestUtils.serializeAndRecover(tableau));
      }
  
      private LinearObjectiveFunction createFunction() {
          return new LinearObjectiveFunction(new double[] {15, 10}, 0);
      }
  
      private Collection<LinearConstraint> createConstraints() {
          Collection<LinearConstraint> constraints = new ArrayList<LinearConstraint>();
         constraints.add(new LinearConstraint(new double[] {1, 0}, Relationship.LEQ, 2));
         constraints.add(new LinearConstraint(new double[] {0, 1}, Relationship.LEQ, 3));
         constraints.add(new LinearConstraint(new double[] {1, 1}, Relationship.EQ, 4));
         return constraints;
     }
 
     private void customAssertMatrixEquals(double[][] expected, double[][] result) {
         assertEquals(expected.length, result.length, "Wrong number of rows.");
         for (int i = 0; i < expected.length; i++) {
             assertEquals(expected[i].length, result[i].length, "Wrong number of columns.");
             for (int j = 0; j < expected[i].length; j++) {
                 assertEquals(expected[i][j], result[i][j], 1.0e-15, "Wrong value at position [" + i + "," + j + "]");
             }
         }
     }
 }