Business Objects & Instantiation

Visualization

The image below visualizes the data created below. For this example we have a chess-board of size 8x8.

Program instance

Instantiation of the dimensions of the board, the Model, as well as the Solver and an empty Solution.
Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace QueensProblem
{
    using OPTANO.Modeling.Common;
    using OPTANO.Modeling.Optimization;
    using OPTANO.Modeling.Optimization.Configuration;
    using OPTANO.Modeling.Optimization.Solver.Gurobi810;
    using System.Collections;

    /// <summary>
    /// Demo program solving the n-Queens Problem
    /// </summary>
    class Program
    {
        /// <summary>
        /// The main method
        /// </summary>
        /// <param name="args">
        /// no arguments required
        /// </param>
        static void Main(string[] args)
        {
            // set size of the board - board is always a square
            int dimension = 8;

            // Use long names for easier debugging/model understanding.
            var config = new Configuration();
            config.NameHandling = NameHandlingStyle.UniqueLongNames;
            config.ComputeRemovedVariables = true;
            using (var scope = new ModelScope(config))
            {
                // create a model, based on given data and the model scope
                var queensModel = new QueensModel(dimension);

                // Get a solver instance, change your solver
                using (var solver = new GurobiSolver())
                {
                    // solve the model
                    var solution = solver.Solve(queensModel.Model);

                    // import the results back into the model 
                    queensModel.Model.VariableCollections.ForEach(vc => vc.SetVariableValues(solution.VariableValues));

                    // print objective and variable decisions
                    Console.WriteLine($"{solution.ObjectiveValues.Single()}");
                    Console.WriteLine("Result: ");

                    foreach (var row in Enumerable.Range(0, dimension))
                    {
                        foreach (var col in Enumerable.Range(0, dimension))
                        {
                            Console.Write(string.Format(queensModel.y[row, col].Value + "  "));
                        }

                        Console.WriteLine();
                    }

                    Console.ReadLine();
                }
            }
        }
    }
}

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