Backport samples from g3 to gh

ortools/linear_solver/samples/MipVarArray.java

@@ -0,0 +1,110 @@
+// Copyright 2010-2018 Google LLC
+// 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.
+
+// MIP example that uses a variable array.
+// [START program]
+package com.google.ortools.linearsolver.samples;
+// [START import]
+import com.google.ortools.linearsolver.MPConstraint;
+import com.google.ortools.linearsolver.MPObjective;
+import com.google.ortools.linearsolver.MPSolver;
+import com.google.ortools.linearsolver.MPVariable;
+// [END import]
+
+// [START program_part1]
+/** MIP example with a variable array. */
+public class MipVarArray {
+  static {
+    System.loadLibrary("jniortools");
+  }
+  // [START data_model]
+  static class DataModel {
+    public final double[][] constraintCoeffs = {
+        {5, 7, 9, 2, 1},
+        {18, 4, -9, 10, 12},
+        {4, 7, 3, 8, 5},
+        {5, 13, 16, 3, -7},
+    };
+    public final double[] bounds = {250, 285, 211, 315};
+    public final double[] objCoeffs = {7, 8, 2, 9, 6};
+    public final int numVars = 5;
+    public final int numConstraints = 4;
+  }
+  // [END data_model]
+
+  public static void main(String[] args) throws Exception {
+    // [START data]
+    final DataModel data = new DataModel();
+    // [END data]
+    // [END program_part1]
+
+    // [START solver]
+    // Create the linear solver with the CBC backend.
+    MPSolver solver = new MPSolver(
+        "SimpleMipProgram", MPSolver.OptimizationProblemType.CBC_MIXED_INTEGER_PROGRAMMING);
+    // [END solver]
+
+    // [START program_part2]
+    // [START variables]
+    double infinity = java.lang.Double.POSITIVE_INFINITY;
+    MPVariable[] x = new MPVariable[data.numVars];
+    for (int j = 0; j < data.numVars; ++j) {
+      x[j] = solver.makeIntVar(0.0, infinity, "");
+    }
+    System.out.println("Number of variables = " + solver.numVariables());
+    // [END variables]
+
+    // [START constraints]
+    // Create the constraints.
+    for (int i = 0; i < data.numConstraints; ++i) {
+      MPConstraint constraint = solver.makeConstraint(0, data.bounds[i], "");
+      for (int j = 0; j < data.numVars; ++j) {
+        constraint.setCoefficient(x[j], data.constraintCoeffs[i][j]);
+      }
+    }
+    System.out.println("Number of constraints = " + solver.numConstraints());
+    // [END constraints]
+
+    // [START objective]
+    MPObjective objective = solver.objective();
+    for (int j = 0; j < data.numVars; ++j) {
+      objective.setCoefficient(x[j], data.objCoeffs[j]);
+    }
+    objective.setMaximization();
+    // [END objective]
+
+    // [START solve]
+    final MPSolver.ResultStatus resultStatus = solver.solve();
+    // [END solve]
+
+    // [START print_solution]
+    // Check that the problem has an optimal solution.
+    if (resultStatus == MPSolver.ResultStatus.OPTIMAL) {
+      System.out.println("Objective value = " + objective.value());
+      for (int j = 0; j < data.numVars; ++j) {
+        System.out.println("x[" + j + "] = " + x[j].solutionValue());
+      }
+      System.out.println();
+      System.out.println("Problem solved in " + solver.wallTime() + " milliseconds");
+      System.out.println("Problem solved in " + solver.iterations() + " iterations");
+      System.out.println("Problem solved in " + solver.nodes() + " branch-and-bound nodes");
+    } else {
+      System.err.println("The problem does not have an optimal solution.");
+    }
+    // [END print_solution]
+  }
+
+  private MipVarArray() {}
+}
+// [END program_part2]
+// [END program]