content: /*
   * Copyright (C) 2015 The Android Open Source Project
   *
   * Licensed 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
   *
   *      http://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.
   */
  package androidx.constraintlayout.core;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  
  import org.junit.Before;
  import org.junit.Test;
  
  public class LinearSystemTest {
  
      LinearSystem mLS;
  
      @Before
      public void setUp() {
          mLS = new LinearSystem();
          LinearEquation.resetNaming();
      }
  
      void add(LinearEquation equation) {
          ArrayRow row1 = LinearEquation.createRowFromEquation(mLS, equation);
          mLS.addConstraint(row1);
      }
  
      void add(LinearEquation equation, int strength) {
          System.out.println("Add equation <" + equation + ">");
          ArrayRow row1 = LinearEquation.createRowFromEquation(mLS, equation);
          System.out.println("Add equation row <" + row1 + ">");
          row1.addError(mLS, strength);
          mLS.addConstraint(row1);
      }
  
      @Test
      public void testMinMax() {
          // this shows how basic min/max + wrap works.
          // Need to modify ConstraintWidget to generate this.
  //        solver.addConstraint(new ClLinearEquation(Rl, 0));
  //        solver.addConstraint(new ClLinearEquation(Al, 0));
  //        solver.addConstraint(new ClLinearEquation(Bl, 0));
  //        solver.addConstraint(new ClLinearEquation(Br, Plus(Bl, 1000)));
  //        solver.addConstraint(new ClLinearEquation(Al,
  //              new ClLinearExpression(Rl), ClStrength.weak));
  //        solver.addConstraint(new ClLinearEquation(Ar,
  //              new ClLinearExpression(Rr), ClStrength.weak));
  //        solver.addConstraint(new ClLinearInequality(Ar, GEQ, Plus(Al, 150), ClStrength.medium));
  //        solver.addConstraint(new ClLinearInequality(Ar, LEQ, Plus(Al, 200), ClStrength.medium));
  //        solver.addConstraint(new ClLinearInequality(Rr, GEQ, new ClLinearExpression(Br)));
  //        solver.addConstraint(new ClLinearInequality(Rr, GEQ, new ClLinearExpression(Ar)));
          add(new LinearEquation(mLS).var("Rl").equalsTo().var(0));
  //        add(new LinearEquation(s).var("Al").equalsTo().var(0));
  //        add(new LinearEquation(s).var("Bl").equalsTo().var(0));
          add(new LinearEquation(mLS).var("Br").equalsTo().var("Bl").plus(300));
          add(new LinearEquation(mLS).var("Al").equalsTo().var("Rl"), 1);
          add(new LinearEquation(mLS).var("Ar").equalsTo().var("Rr"), 1);
          add(new LinearEquation(mLS).var("Ar").greaterThan().var("Al").plus(150), 2);
          add(new LinearEquation(mLS).var("Ar").lowerThan().var("Al").plus(200), 2);
          add(new LinearEquation(mLS).var("Rr").greaterThan().var("Ar"));
          add(new LinearEquation(mLS).var("Rr").greaterThan().var("Br"));
          add(new LinearEquation(mLS).var("Al").minus("Rl").equalsTo().var("Rr").minus("Ar"));
          add(new LinearEquation(mLS).var("Bl").minus("Rl").equalsTo().var("Rr").minus("Br"));
          try {
              mLS.minimize();
          } catch (Exception e) {
              e.printStackTrace();
          }
          System.out.println("Result: ");
          mLS.displayReadableRows();
          assertEquals(mLS.getValueFor("Al"), 50.0f, 0f);
          assertEquals(mLS.getValueFor("Ar"), 250.0f, 0f);
          assertEquals(mLS.getValueFor("Bl"), 0.0f, 0f);
          assertEquals(mLS.getValueFor("Br"), 300.0f, 0f);
          assertEquals(mLS.getValueFor("Rr"), 300.0f, 0f);
      }
  
      @Test
      public void testPriorityBasic() {
          add(new LinearEquation(mLS).var(2, "Xm").equalsTo().var("Xl").plus("Xr"));
          add(new LinearEquation(mLS).var("Xl").plus(10).lowerThan().var("Xr"));
          //       add(new LinearEquation(s).var("Xl").greaterThan().var(0));
          add(new LinearEquation(mLS).var("Xr").lowerThan().var(100));
          add(new LinearEquation(mLS).var("Xm").equalsTo().var(50), 2);
          add(new LinearEquation(mLS).var("Xl").equalsTo().var(30), 1);
          add(new LinearEquation(mLS).var("Xr").equalsTo().var(60), 1);
          try {
              mLS.minimize();
          } catch (Exception e) {
              e.printStackTrace();
          }
          System.out.println("Result: ");
          mLS.displayReadableRows();
          assertEquals(mLS.getValueFor("Xm"), 50.0f, 0f); // 50
          assertEquals(mLS.getValueFor("Xl"), 40.0f, 0f); // 30
          assertEquals(mLS.getValueFor("Xr"), 60.0f, 0f); // 70
      }
  
      @Test
      public void testPriorities() {
          // | <- a -> | b
          // a - zero = c - a
          // 2a = c + zero
          // a = (c + zero ) / 2
          add(new LinearEquation(mLS).var("b").equalsTo().var(100), 3);
          add(new LinearEquation(mLS).var("zero").equalsTo().var(0), 3);
          add(new LinearEquation(mLS).var("a").equalsTo().var(300), 0);
          add(new LinearEquation(mLS).var("c").equalsTo().var(200), 0);
  
          add(new LinearEquation(mLS).var("c").lowerThan().var("b").minus(10), 2);
          add(new LinearEquation(mLS).var("a").lowerThan().var("c"), 2);
  
          add(new LinearEquation(mLS).var("a").minus("zero").equalsTo().var("c").minus("a"), 1);
  
          try {
              mLS.minimize();
          } catch (Exception e) {
              e.printStackTrace();
          }
          System.out.println("Result: ");
          mLS.displayReadableRows();
          assertEquals(mLS.getValueFor("zero"), 0.0f, 0f);
          assertEquals(mLS.getValueFor("a"), 45.0f, 0f);
          assertEquals(mLS.getValueFor("b"), 100.0f, 0f);
          assertEquals(mLS.getValueFor("c"), 90.0f, 0f);
      }
  
      @Test
      public void testOptimizeAndPriority() {
          mLS.reset();
          LinearEquation eq1 = new LinearEquation(mLS);
          LinearEquation eq2 = new LinearEquation(mLS);
          LinearEquation eq3 = new LinearEquation(mLS);
          LinearEquation eq4 = new LinearEquation(mLS);
          LinearEquation eq5 = new LinearEquation(mLS);
          LinearEquation eq6 = new LinearEquation(mLS);
          LinearEquation eq7 = new LinearEquation(mLS);
          LinearEquation eq8 = new LinearEquation(mLS);
          LinearEquation eq9 = new LinearEquation(mLS);
          LinearEquation eq10 = new LinearEquation(mLS);
  
          eq1.var("Root.left").equalsTo().var(0);
          eq2.var("Root.right").equalsTo().var(600);
          eq3.var("A.right").equalsTo().var("A.left").plus(100); //*
          eq4.var("A.left").greaterThan().var("Root.left"); //*
          eq10.var("A.left").equalsTo().var("Root.left"); //*
          eq5.var("A.right").lowerThan().var("B.left");
          eq6.var("B.right").greaterThan().var("B.left");
          eq7.var("B.right").lowerThan().var("Root.right");
          eq8.var("B.left").equalsTo().var("A.right");
          eq9.var("B.right").greaterThan().var("Root.right");
  
          ArrayRow row1 = LinearEquation.createRowFromEquation(mLS, eq1);
          mLS.addConstraint(row1);
  
          ArrayRow row2 = LinearEquation.createRowFromEquation(mLS, eq2);
          mLS.addConstraint(row2);
  
          ArrayRow row3 = LinearEquation.createRowFromEquation(mLS, eq3);
          mLS.addConstraint(row3);
  
          ArrayRow row10 = LinearEquation.createRowFromEquation(mLS, eq10);
          mLS.addSingleError(row10, 1, SolverVariable.STRENGTH_MEDIUM);
          mLS.addSingleError(row10, -1, SolverVariable.STRENGTH_MEDIUM);
          mLS.addConstraint(row10);
  
          ArrayRow row4 = LinearEquation.createRowFromEquation(mLS, eq4);
          mLS.addSingleError(row4, -1, SolverVariable.STRENGTH_HIGH);
          mLS.addConstraint(row4);
  
          ArrayRow row5 = LinearEquation.createRowFromEquation(mLS, eq5);
          mLS.addSingleError(row5, 1, SolverVariable.STRENGTH_MEDIUM);
          mLS.addConstraint(row5);
  
          ArrayRow row6 = LinearEquation.createRowFromEquation(mLS, eq6);
          mLS.addSingleError(row6, -1, SolverVariable.STRENGTH_LOW);
          mLS.addConstraint(row6);
  
          ArrayRow row7 = LinearEquation.createRowFromEquation(mLS, eq7);
          mLS.addSingleError(row7, 1, SolverVariable.STRENGTH_LOW);
          mLS.addConstraint(row7);
  
          ArrayRow row8 = LinearEquation.createRowFromEquation(mLS, eq8);
          row8.addError(mLS, SolverVariable.STRENGTH_LOW);
          mLS.addConstraint(row8);
  
          ArrayRow row9 = LinearEquation.createRowFromEquation(mLS, eq9);
          mLS.addSingleError(row9, -1, SolverVariable.STRENGTH_LOW);
          mLS.addConstraint(row9);
  
          try {
              mLS.minimize();
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      @Test
      public void testPriority() {
          for (int i = 0; i < 3; i++) {
              System.out.println("\n*** TEST PRIORITY ***\n");
              mLS.reset();
              LinearEquation eq1 = new LinearEquation(mLS);
              eq1.var("A").equalsTo().var(10);
              ArrayRow row1 = LinearEquation.createRowFromEquation(mLS, eq1);
              row1.addError(mLS, i % 3);
              mLS.addConstraint(row1);
  
              LinearEquation eq2 = new LinearEquation(mLS);
              eq2.var("A").equalsTo().var(100);
              ArrayRow row2 = LinearEquation.createRowFromEquation(mLS, eq2);
              row2.addError(mLS, (i + 1) % 3);
              mLS.addConstraint(row2);
  
              LinearEquation eq3 = new LinearEquation(mLS);
              eq3.var("A").equalsTo().var(1000);
              ArrayRow row3 = LinearEquation.createRowFromEquation(mLS, eq3);
              row3.addError(mLS, (i + 2) % 3);
              mLS.addConstraint(row3);
  
              try {
                  mLS.minimize();
              } catch (Exception e) {
                  e.printStackTrace();
              }
              System.out.println("Check at iteration " + i);
              mLS.displayReadableRows();
              if (i == 0) {
                  assertEquals(mLS.getValueFor("A"), 1000.0f, 0f);
              } else if (i == 1) {
                  assertEquals(mLS.getValueFor("A"), 100.0f, 0f);
              } else if (i == 2) {
                  assertEquals(mLS.getValueFor("A"), 10.0f, 0f);
              }
          }
      }
  
      @Test
      public void testAddEquation1() {
          LinearEquation e1 = new LinearEquation(mLS);
          e1.var("W3.left").equalsTo().var(0);
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e1));
          //s.rebuildGoalFromErrors();
          String result = mLS.getGoal().toString();
          assertTrue((result.equals("0 = 0.0") || result.equals(" goal -> (0.0) : ")));
          assertEquals(mLS.getValueFor("W3.left"), 0.0f, 0f);
      }
  
      @Test
      public void testAddEquation2() {
          LinearEquation e1 = new LinearEquation(mLS);
          e1.var("W3.left").equalsTo().var(0);
          LinearEquation e2 = new LinearEquation(mLS);
          e2.var("W3.right").equalsTo().var(600);
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e1));
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e2));
          //s.rebuildGoalFromErrors();
          String result = mLS.getGoal().toString();
          assertTrue((result.equals("0 = 0.0") || result.equals(" goal -> (0.0) : ")));
          assertEquals(mLS.getValueFor("W3.left"), 0.0f, 0f);
          assertEquals(mLS.getValueFor("W3.right"), 600.0f, 0f);
      }
  
      @Test
      public void testAddEquation3() {
          LinearEquation e1 = new LinearEquation(mLS);
          e1.var("W3.left").equalsTo().var(0);
          LinearEquation e2 = new LinearEquation(mLS);
          e2.var("W3.right").equalsTo().var(600);
          LinearEquation left_constraint = new LinearEquation(mLS);
          left_constraint.var("W4.left").equalsTo().var("W3.left"); // left constraint
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e1));
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e2));
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, left_constraint)); // left
          //s.rebuildGoalFromErrors();
          assertEquals(mLS.getValueFor("W3.left"), 0.0f, 0f);
          assertEquals(mLS.getValueFor("W3.right"), 600.0f, 0f);
          assertEquals(mLS.getValueFor("W4.left"), 0.0f, 0f);
      }
  
      @Test
      public void testAddEquation4() {
          LinearEquation e1 = new LinearEquation(mLS);
          LinearEquation e2 = new LinearEquation(mLS);
          LinearEquation e3 = new LinearEquation(mLS);
          LinearEquation e4 = new LinearEquation(mLS);
          e1.var(2, "Xm").equalsTo().var("Xl").plus("Xr");
          LinearSystem.Row goalRow = mLS.getGoal();
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e1)); // 2 Xm = Xl + Xr
          goalRow.addError(mLS.getVariable("Xm", SolverVariable.Type.ERROR));
          goalRow.addError(mLS.getVariable("Xl", SolverVariable.Type.ERROR));
  //        assertEquals(s.getRow(0).toReadableString(), "Xm = 0.5 Xl + 0.5 Xr", 0f);
          e2.var("Xl").plus(10).lowerThan().var("Xr");
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e2)); // Xl + 10 <= Xr
  
  //        assertEquals(s.getRow(0).toReadableString(), "Xm = 5.0 + Xl + 0.5 s1", 0f);
  //        assertEquals(s.getRow(1).toReadableString(), "Xr = 10.0 + Xl + s1", 0f);
          e3.var("Xl").greaterThan().var(-10);
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e3)); // Xl >= -10
  //        assertEquals(s.getRow(0).toReadableString(), "Xm = -5.0 + 0.5 s1 + s2", 0f);
  //        assertEquals(s.getRow(1).toReadableString(), "Xr = s1 + s2", 0f);
  //        assertEquals(s.getRow(2).toReadableString(), "Xl = -10.0 + s2", 0f);
          e4.var("Xr").lowerThan().var(100);
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e4)); // Xr <= 100
  //        assertEquals(s.getRow(0).toReadableString(), "Xm = 45.0 + 0.5 s2 - 0.5 s3", 0f);
  //        assertEquals(s.getRow(1).toReadableString(), "Xr = 100.0 - s3", 0f);
  //        assertEquals(s.getRow(2).toReadableString(), "Xl = -10.0 + s2", 0f);
  //        assertEquals(s.getRow(3).toReadableString(), "s1 = 100.0 - s2 - s3", 0f);
          //s.rebuildGoalFromErrors();
  //        assertEquals(s.getGoal().toString(), "Goal: ", 0f);
          LinearEquation goal = new LinearEquation(mLS);
          goal.var("Xm").minus("Xl");
          try {
              mLS.minimizeGoal(LinearEquation.createRowFromEquation(mLS, goal)); //s.getGoal());
          } catch (Exception e) {
              e.printStackTrace();
          }
          int xl = (int) mLS.getValueFor("Xl");
          int xm = (int) mLS.getValueFor("Xm");
          int xr = (int) mLS.getValueFor("Xr");
  //        assertEquals(xl, -10, 0f);
  //        assertEquals(xm, 45, 0f);
  //        assertEquals(xr, 100, 0f);
          LinearEquation e5 = new LinearEquation(mLS);
          e5.var("Xm").equalsTo().var(50);
          mLS.addConstraint(LinearEquation.createRowFromEquation(mLS, e5));
          try {
  //            s.minimizeGoal(s.getGoal());
  //            s.minimizeGoal(LinearEquation.createRowFromEquation(s, goal)); //s.getGoal());
              mLS.minimizeGoal(goalRow);
          } catch (Exception e) {
              e.printStackTrace();
          }
          xl = (int) mLS.getValueFor("Xl");
          xm = (int) mLS.getValueFor("Xm");
          xr = (int) mLS.getValueFor("Xr");
          assertEquals(xl, 0);
          assertEquals(xm, 50);
          assertEquals(xr, 100);
      }
  
  }
  