org.chocosolver.examples.integer.WarehouseLocation Maven / Gradle / Ivy
/*
* This file is part of examples, http://choco-solver.org/
*
* Copyright (c) 2024, IMT Atlantique. All rights reserved.
*
* Licensed under the BSD 4-clause license.
*
* See LICENSE file in the project root for full license information.
*/
package org.chocosolver.examples.integer;
import org.chocosolver.examples.AbstractProblem;
import org.chocosolver.solver.Model;
import org.chocosolver.solver.Solver;
import org.chocosolver.solver.search.loop.monitors.IMonitorSolution;
import org.chocosolver.solver.search.strategy.Search;
import org.chocosolver.solver.search.strategy.selectors.values.IntDomainMiddle;
import org.chocosolver.solver.search.strategy.selectors.variables.FirstFail;
import org.chocosolver.solver.search.strategy.selectors.variables.Smallest;
import org.chocosolver.solver.search.strategy.selectors.variables.VariableSelectorWithTies;
import org.chocosolver.solver.variables.BoolVar;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.util.ESat;
import org.chocosolver.util.tools.ArrayUtils;
import org.kohsuke.args4j.Option;
import java.util.Arrays;
import static org.chocosolver.util.tools.ArrayUtils.append;
/**
* CSPLib prob034:
* "In the Warehouse Location problem (WLP), a company considers opening warehouses
* at some candidate locations in order to supply its existing stores. Each possible warehouse
* has the same maintenance C, and a K designating the maximum number of stores
* that it can supply. Each store must be supplied by exactly one open warehouse.
* The supply C to a store depends on the warehouse. The objective is to determine which
* warehouses to open, and which of these warehouses should supply the various stores, such
* that the sum of the maintenance and supply costs is minimized."
*
*
* @author Charles Prud'homme
* @since 04/08/11
*/
public class WarehouseLocation extends AbstractProblem {
@Option(name = "-d", aliases = "--data", usage = "Warehouse location instance.", required = false)
Data data = Data.small;
int W, S, C;
int[] K;
int[][] P;
IntVar[] supplier;
BoolVar[] open;
IntVar[] cost;
IntVar tot_cost;
public void setUp() {
int k = 0;
W = data.data[k++];
S = data.data[k++];
C = data.data[k++];
K = new int[W];
for (int i = 0; i < W; i++) {
K[i] = data.data[k++];
}
P = new int[S][W];
for (int j = 0; j < S; j++) {
for (int i = 0; i < W; i++) {
P[j][i] = data.data[k++];
}
}
}
@Override
public void buildModel() {
model = new Model();
setUp();
supplier = model.intVarArray("sup", S, 1, W, false);
open = model.boolVarArray("o", W);
cost = model.intVarArray("cPs", S, 1, 96, true);
tot_cost = model.intVar("C", 0, 99999, true);
for (int s = 0; s < S; s++) {
// A warehouse is open, if it supplies to a store
model.element(model.intVar(1), open, supplier[s], 1).post();
// Compute C for each warehouse
model.element(cost[s], P[s], supplier[s], 1).post();
}
for (int w = 0; w < W; w++) {
IntVar occ = model.intVar("occur_" + w, 0, K[w], true);
model.count(w + 1, supplier, occ).post();
occ.ge(open[w]).post();
// occ.le(open[w].mul(100)).post();
}
int[] coeffs = new int[W + S];
Arrays.fill(coeffs, 0, W, C);
Arrays.fill(coeffs, W, W + S, 1);
model.scalar(ArrayUtils.append(open, cost), coeffs, "=", tot_cost).post();
}
@Override
public void configureSearch() {
Solver solver = model.getSolver();
solver.setSearch(Search.intVarSearch(
new VariableSelectorWithTies<>(
new FirstFail(model),
new Smallest()),
new IntDomainMiddle(false),
append(supplier, cost, open)));
}
@Override
public void solve() {
Solver solver = model.getSolver();
// solver.setCBJLearning(false, false);
solver.plugMonitor((IMonitorSolution) () -> prettyPrint());
solver.showShortStatistics();
solver.getObjectiveManager().setCutComputer(obj -> obj);
solver.findOptimalSolution(tot_cost, false);
// model.setObjective(ResolutionPolicy.MINIMIZE, tot_cost);
// while (solver.solve()) {
// do something on solution
// }
}
private void prettyOut() {
System.out.println("Warehouse location problem");
if (model.getSolver().isFeasible() == ESat.TRUE) {
prettyPrint();
}
}
private void prettyPrint() {
StringBuilder st = new StringBuilder();
st.append("Solution #").append(model.getSolver().getSolutionCount()).append("\n");
for (int i = 0; i < W; i++) {
if (open[i].getValue() > 0) {
st.append(String.format("\tWarehouse %d supplies customers : ", (i + 1)));
for (int j = 0; j < S; j++) {
if (supplier[j].getValue() == (i + 1)) {
st.append(String.format("%d ", (j + 1)));
}
}
st.append("\n");
}
}
st.append("\tTotal C: ").append(tot_cost.getValue());
System.out.println(st);
}
public static void main(String[] args) {
new WarehouseLocation().execute(args);
}
////////////////////////////////////////// DATA ////////////////////////////////////////////////////////////////////
enum Data {
small(new int[]{
5, 10, 30, //W = 5, S = 10, C = 30
1, 4, 2, 1, 3, // K
// P
20, 24, 11, 25, 30,
28, 27, 82, 83, 74,
74, 97, 71, 96, 70,
2, 55, 73, 69, 61,
46, 96, 59, 83, 4,
42, 22, 29, 67, 59,
1, 5, 73, 59, 56,
10, 73, 13, 43, 96,
93, 35, 63, 85, 46,
47, 65, 55, 71, 95
}),
med(new int[]{
7, 14, 30,
1, 4, 2, 1, 3, 3, 1,
// P
20, 24, 11, 25, 30, 15, 23,
28, 27, 82, 83, 74, 24, 11,
74, 97, 71, 96, 70, 82, 27,
2, 55, 73, 69, 61, 10, 96,
46, 96, 59, 83, 4, 36, 58,
42, 22, 29, 67, 59, 64, 23,
1, 5, 73, 59, 56, 48, 13,
10, 73, 13, 43, 96, 1, 82,
93, 35, 63, 85, 46, 99, 17,
47, 65, 55, 71, 95, 25, 35,
67, 59, 42, 22, 2, 46, 96,
56, 1, 5, 73, 5, 42, 22,
43, 96, 10, 73, 1, 1, 5,
85, 46, 93, 35, 6, 10, 73,
}),
large(new int[]{
10, 20, 30,
1, 4, 2, 1, 3, 1, 4, 2, 1, 3, // K
// P
20, 24, 11, 25, 30, 20, 24, 11, 25, 30,
28, 27, 82, 83, 74, 28, 27, 82, 83, 74,
74, 97, 71, 96, 70, 74, 97, 71, 96, 70,
2, 55, 73, 69, 61, 2, 55, 73, 69, 61,
46, 96, 59, 83, 4, 46, 96, 59, 83, 4,
42, 22, 29, 67, 59, 42, 22, 29, 67, 59,
1, 5, 73, 59, 56, 1, 5, 73, 59, 56,
10, 73, 13, 43, 96, 10, 73, 13, 43, 96,
93, 35, 63, 85, 46, 93, 35, 63, 85, 46,
47, 65, 55, 71, 95, 47, 65, 55, 71, 95,
20, 24, 11, 25, 30, 20, 24, 11, 25, 30,
28, 27, 82, 83, 74, 28, 27, 82, 83, 74,
74, 97, 71, 96, 70, 74, 97, 71, 96, 70,
2, 55, 73, 69, 61, 2, 55, 73, 69, 61,
46, 96, 59, 83, 4, 46, 96, 59, 83, 4,
42, 22, 29, 67, 59, 42, 22, 29, 67, 59,
1, 5, 73, 59, 56, 1, 5, 73, 59, 56,
10, 73, 13, 43, 96, 10, 73, 13, 43, 96,
93, 35, 63, 85, 46, 93, 35, 63, 85, 46,
47, 65, 55, 71, 95, 47, 65, 55, 71, 95
});
final int[] data;
Data(int[] data) {
this.data = data;
}
public int get(int i) {
return data[i];
}
}
}
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