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[CP-SAT] Add AtMostOne/AtLeastOne/ExactlyOne constraint in all languages; rewrite linear expressions in java

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This commit is contained in:
Laurent Perron
2022-01-03 09:43:59 +01:00
parent ce02461741
commit 62d506143b
34 changed files with 754 additions and 525 deletions
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30
ortools/sat/samples/MultipleKnapsackSat.java
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@@ -19,8 +19,11 @@ import com.google.ortools.Loader;
import com.google.ortools.sat.CpModel;
import com.google.ortools.sat.CpSolver;
import com.google.ortools.sat.CpSolverStatus;
import com.google.ortools.sat.IntVar;
import com.google.ortools.sat.LinearExpr;
import com.google.ortools.sat.LinearExprBuilder;
import com.google.ortools.sat.Literal;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.IntStream;
// [END import]
@@ -46,7 +49,7 @@ public class MultipleKnapsackSat {
// Variables.
// [START variables]
IntVar[][] x = new IntVar[numItems][numBins];
Literal[][] x = new Literal[numItems][numBins];
for (int i : allItems) {
for (int b : allBins) {
x[i][b] = model.newBoolVar("x_" + i + "_" + b);
@@ -58,36 +61,33 @@ public class MultipleKnapsackSat {
// [START constraints]
// Each item is assigned to at most one bin.
for (int i : allItems) {
IntVar[] vars = new IntVar[numBins];
List<Literal> bins = new ArrayList<>();
for (int b : allBins) {
vars[b] = x[i][b];
bins.add(x[i][b]);
}
model.addLessOrEqual(LinearExpr.sum(vars), 1);
model.addAtMostOne(bins);
}
// The amount packed in each bin cannot exceed its capacity.
for (int b : allBins) {
IntVar[] vars = new IntVar[numItems];
LinearExprBuilder load = LinearExpr.newBuilder();
for (int i : allItems) {
vars[i] = x[i][b];
load.addTerm(x[i][b], weights[i]);
}
model.addLessOrEqual(LinearExpr.scalProd(vars, weights), binCapacities[b]);
model.addLessOrEqual(load.build(), binCapacities[b]);
}
// [END constraints]
// Objective.
// [START objective]
// Maximize total value of packed items.
IntVar[] objectiveVars = new IntVar[numItems * numBins];
int[] objectiveValues = new int[numItems * numBins];
LinearExprBuilder obj = LinearExpr.newBuilder();
for (int i : allItems) {
for (int b : allBins) {
int k = i * numBins + b;
objectiveVars[k] = x[i][b];
objectiveValues[k] = values[i];
obj.addTerm(x[i][b], values[i]);
}
}
model.maximize(LinearExpr.scalProd(objectiveVars, objectiveValues));
model.maximize(obj.build());
// [END objective]
// [START solve]
@@ -105,7 +105,7 @@ public class MultipleKnapsackSat {
long binValue = 0;
System.out.println("Bin " + b);
for (int i : allItems) {
if (solver.value(x[i][b]) > 0) {
if (solver.booleanValue(x[i][b])) {
System.out.println("Item " + i + " weight: " + weights[i] + " value: " + values[i]);
binWeight += weights[i];
binValue += values[i];