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add C# sat code samples in ortools/sat/samples; remove old code_samples_sat.* files

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Laurent Perron
2018-07-17 14:00:18 -07:00
parent 9380710b82
commit 0152168fb7
25 changed files with 641 additions and 999 deletions
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examples/dotnet/csharp-netfx/code_samples_sat.cs
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// Copyright 2010-2017 Google
// 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.
using System;
using Google.OrTools.Sat;
public class VarArraySolutionPrinter : CpSolverSolutionCallback
{
public VarArraySolutionPrinter(IntVar[] variables)
{
variables_ = variables;
}
public override void OnSolutionCallback()
{
{
Console.WriteLine(String.Format("Solution #{0}: time = {1:F2} s",
solution_count_, WallTime()));
foreach (IntVar v in variables_)
{
Console.WriteLine(
String.Format(" {0} = {1}", v.ShortString(), Value(v)));
}
solution_count_++;
}
}
public int SolutionCount()
{
return solution_count_;
}
private int solution_count_;
private IntVar[] variables_;
}
public class VarArraySolutionPrinterWithObjective : CpSolverSolutionCallback
{
public VarArraySolutionPrinterWithObjective(IntVar[] variables)
{
variables_ = variables;
}
public override void OnSolutionCallback()
{
{
Console.WriteLine(String.Format("Solution #{0}: time = {1:F2} s",
solution_count_, WallTime()));
Console.WriteLine(
String.Format(" objective value = {0}", ObjectiveValue()));
foreach (IntVar v in variables_)
{
Console.WriteLine(
String.Format(" {0} = {1}", v.ShortString(), Value(v)));
}
solution_count_++;
}
}
public int SolutionCount()
{
return solution_count_;
}
private int solution_count_;
private IntVar[] variables_;
}
public class CodeSamplesSat
{
static void CodeSample()
{
// Creates the model.
CpModel model = new CpModel();
// Creates the Boolean variable.
IntVar x = model.NewBoolVar("x");
}
static void LiteralSample()
{
CpModel model = new CpModel();
IntVar x = model.NewBoolVar("x");
ILiteral not_x = x.Not();
}
static void BoolOrSample()
{
CpModel model = new CpModel();
IntVar x = model.NewBoolVar("x");
IntVar y = model.NewBoolVar("y");
model.AddBoolOr(new ILiteral[] {x, y.Not()});
}
static void ReifiedSample()
{
CpModel model = new CpModel();
IntVar x = model.NewBoolVar("x");
IntVar y = model.NewBoolVar("y");
IntVar b = model.NewBoolVar("b");
// First version using a half-reified bool and.
model.AddBoolAnd(new ILiteral[] {x, y.Not()}).OnlyEnforceIf(b);
// Second version using implications.
model.AddImplication(b, x);
model.AddImplication(b, y.Not());
// Third version using bool or.
model.AddBoolOr(new ILiteral[] {b.Not(), x});
model.AddBoolOr(new ILiteral[] {b.Not(), y.Not()});
}
static void RabbitsAndPheasants()
{
// Creates the model.
CpModel model = new CpModel();
// Creates the variables.
IntVar r = model.NewIntVar(0, 100, "r");
IntVar p = model.NewIntVar(0, 100, "p");
// 20 heads.
model.Add(r + p == 20);
// 56 legs.
model.Add(4 * r + 2 * p == 56);
// Creates a solver and solves the model.
CpSolver solver = new CpSolver();
CpSolverStatus status = solver.Solve(model);
if (status == CpSolverStatus.Feasible)
{
Console.WriteLine(solver.Value(r) + " rabbits, and " +
solver.Value(p) + " pheasants");
}
}
static void BinpackingProblem()
{
// Data.
int bin_capacity = 100;
int slack_capacity = 20;
int num_bins = 10;
int[,] items = new int[,] { {20, 12}, {15, 12}, {30, 8}, {45, 5} };
int num_items = items.GetLength(0);
// Model.
CpModel model = new CpModel();
// Main variables.
IntVar[,] x = new IntVar[num_items, num_bins];
for (int i = 0; i < num_items; ++i)
{
int num_copies = items[i, 1];
for (int b = 0; b < num_bins; ++b)
{
x[i, b] = model.NewIntVar(0, num_copies, String.Format("x_{0}_{1}", i, b));
}
}
// Load variables.
IntVar[] load = new IntVar[num_bins];
for (int b = 0; b < num_bins; ++b)
{
load[b] = model.NewIntVar(0, bin_capacity, String.Format("load_{0}", b));
}
// Slack variables.
IntVar[] slacks = new IntVar[num_bins];
for (int b = 0; b < num_bins; ++b)
{
slacks[b] = model.NewBoolVar(String.Format("slack_{0}", b));
}
// Links load and x.
int[] sizes = new int[num_items];
for (int i = 0; i < num_items; ++i) {
sizes[i] = items[i, 0];
}
for (int b = 0; b < num_bins; ++b)
{
IntVar[] tmp = new IntVar[num_items];
for (int i = 0; i < num_items; ++i)
{
tmp[i] = x[i, b];
}
model.Add(load[b] == tmp.ScalProd(sizes));
}
// Place all items.
for (int i = 0; i < num_items; ++i)
{
IntVar[] tmp = new IntVar[num_bins];
for (int b = 0; b < num_bins; ++b)
{
tmp[b] = x[i, b];
}
model.Add(tmp.Sum() == items[i, 1]);
}
// Links load and slack.
int safe_capacity = bin_capacity - slack_capacity;
for (int b = 0; b < num_bins; ++b)
{
// slack[b] => load[b] <= safe_capacity.
model.Add(load[b] <= safe_capacity).OnlyEnforceIf(slacks[b]);
// not(slack[b]) => load[b] > safe_capacity.
model.Add(load[b] > safe_capacity).OnlyEnforceIf(slacks[b].Not());
}
// Maximize sum of slacks.
model.Maximize(slacks.Sum());
// Solves and prints out the solution.
CpSolver solver = new CpSolver();
CpSolverStatus status = solver.Solve(model);
Console.WriteLine(String.Format("Solve status: {0}", status));
if (status == CpSolverStatus.Optimal) {
Console.WriteLine(String.Format("Optimal objective value: {0}",
solver.ObjectiveValue));
for (int b = 0; b < num_bins; ++b)
{
Console.WriteLine(String.Format("load_{0} = {1}",
b, solver.Value(load[b])));
for (int i = 0; i < num_items; ++i)
{
Console.WriteLine(string.Format(" item_{0}_{1} = {2}",
i, b, solver.Value(x[i, b])));
}
}
}
Console.WriteLine("Statistics");
Console.WriteLine(
String.Format(" - conflicts : {0}", solver.NumConflicts()));
Console.WriteLine(
String.Format(" - branches : {0}", solver.NumBranches()));
Console.WriteLine(
String.Format(" - wall time : {0} s", solver.WallTime()));
}
static void IntervalSample()
{
CpModel model = new CpModel();
int horizon = 100;
IntVar start_var = model.NewIntVar(0, horizon, "start");
// C# code supports IntVar or integer constants in intervals.
int duration = 10;
IntVar end_var = model.NewIntVar(0, horizon, "end");
IntervalVar interval =
model.NewIntervalVar(start_var, duration, end_var, "interval");
}
static void OptionalIntervalSample()
{
CpModel model = new CpModel();
int horizon = 100;
IntVar start_var = model.NewIntVar(0, horizon, "start");
// C# code supports IntVar or integer constants in intervals.
int duration = 10;
IntVar end_var = model.NewIntVar(0, horizon, "end");
IntVar presence_var = model.NewBoolVar("presence");
IntervalVar interval = model.NewOptionalIntervalVar(
start_var, duration, end_var, presence_var, "interval");
}
static void MinimalCpSat()
{
// Creates the model.
CpModel model = new CpModel();
// Creates the variables.
int num_vals = 3;
IntVar x = model.NewIntVar(0, num_vals - 1, "x");
IntVar y = model.NewIntVar(0, num_vals - 1, "y");
IntVar z = model.NewIntVar(0, num_vals - 1, "z");
// Creates the constraints.
model.Add(x != y);
// Creates a solver and solves the model.
CpSolver solver = new CpSolver();
CpSolverStatus status = solver.Solve(model);
if (status == CpSolverStatus.Feasible)
{
Console.WriteLine("x = " + solver.Value(x));
Console.WriteLine("y = " + solver.Value(y));
Console.WriteLine("z = " + solver.Value(z));
}
}
static void MinimalCpSatWithTimeLimit()
{
// Creates the model.
CpModel model = new CpModel();
// Creates the variables.
int num_vals = 3;
IntVar x = model.NewIntVar(0, num_vals - 1, "x");
IntVar y = model.NewIntVar(0, num_vals - 1, "y");
IntVar z = model.NewIntVar(0, num_vals - 1, "z");
// Creates the constraints.
model.Add(x != y);
// Creates a solver and solves the model.
CpSolver solver = new CpSolver();
// Adds a time limit. Parameters are stored as strings in the solver.
solver.StringParameters = "max_time_in_seconds:10.0" ;
CpSolverStatus status = solver.Solve(model);
if (status == CpSolverStatus.Feasible)
{
Console.WriteLine("x = " + solver.Value(x));
Console.WriteLine("y = " + solver.Value(y));
Console.WriteLine("z = " + solver.Value(z));
}
}
static void MinimalCpSatPrintIntermediateSolutions()
{
// Creates the model.
CpModel model = new CpModel();
// Creates the variables.
int num_vals = 3;
IntVar x = model.NewIntVar(0, num_vals - 1, "x");
IntVar y = model.NewIntVar(0, num_vals - 1, "y");
IntVar z = model.NewIntVar(0, num_vals - 1, "z");
// Creates the constraints.
model.Add(x != y);
// Create the objective.
model.Maximize(x + 2 * y + 3 * z);
// Creates a solver and solves the model.
CpSolver solver = new CpSolver();
VarArraySolutionPrinterWithObjective cb =
new VarArraySolutionPrinterWithObjective(new IntVar[] {x, y, z});
solver.SearchAllSolutions(model, cb);
Console.WriteLine(String.Format("Number of solutions found: {0}",
cb.SolutionCount()));
}
static void MinimalCpSatAllSolutions()
{
// Creates the model.
CpModel model = new CpModel();
// Creates the variables.
int num_vals = 3;
IntVar x = model.NewIntVar(0, num_vals - 1, "x");
IntVar y = model.NewIntVar(0, num_vals - 1, "y");
IntVar z = model.NewIntVar(0, num_vals - 1, "z");
// Creates the constraints.
model.Add(x != y);
// Creates a solver and solves the model.
CpSolver solver = new CpSolver();
VarArraySolutionPrinter cb =
new VarArraySolutionPrinter(new IntVar[] {x, y, z});
solver.SearchAllSolutions(model, cb);
Console.WriteLine(String.Format("Number of solutions found: {0}",
cb.SolutionCount()));
}
static void Main()
{
Console.WriteLine("--- CodeSample ---");
CodeSample();
Console.WriteLine("--- LiteralSample ---");
LiteralSample();
Console.WriteLine("--- BoolOrSample ---");
BoolOrSample();
Console.WriteLine("--- ReifiedSample ---");
ReifiedSample();
Console.WriteLine("--- RabbitsAndPheasants ---");
RabbitsAndPheasants();
Console.WriteLine("--- BinpackingProblem ---");
BinpackingProblem();
Console.WriteLine("--- IntervalSample ---");
IntervalSample();
Console.WriteLine("--- OptionalIntervalSample ---");
OptionalIntervalSample();
Console.WriteLine("--- MinimalCpSat ---");
MinimalCpSat();
Console.WriteLine("--- MinimalCpSatWithTimeLimit ---");
MinimalCpSatWithTimeLimit();
Console.WriteLine("--- MinimalCpSatPrintIntermediateSolutions ---");
MinimalCpSatPrintIntermediateSolutions();
Console.WriteLine("--- MinimalCpSatAllSolutions ---");
MinimalCpSatAllSolutions();
}
}