Package org.ddolib.examples.pdp

Class PDPLnsMain

java.lang.Object

org.ddolib.examples.pdp.PDPLnsMain

public class PDPLnsMain
extends Object

Entry point for solving the Single Vehicle Pick-up and Delivery Problem (PDP) using a Large Neighborhood Search (LNS) approach combined with Decision Diagram Optimization (DDO).

The Single Vehicle Pick-up and Delivery Problem consists in determining a sequence of pick-ups and deliveries for a single vehicle such that:

• All requests (pick-up and corresponding delivery) are served
• Vehicle capacity and precedence constraints are respected
• The total cost or travel distance is minimized

This class demonstrates how to:

• Generate a PDP instance programmatically
• Define a LnsModel with problem-specific components
• Use a lower bound heuristic to guide the search
• Use a ranking heuristic to prioritize states
• Control the decision diagram width
• Run a Large Neighborhood Search (LNS) optimization
• Print intermediate and final solutions

Instance Configuration

In this example, a random PDP instance is generated with:

• 18 requests
• 2 vehicles (single vehicle may still be assumed for sequencing)
• 3 maximum capacity per vehicle
• Random seed: 1

Model Components

• PDPProblem – defines the pick-up and delivery requests
• PDPFastLowerBound – provides a fast lower bound on the total cost
• PDPRanking – ranks states during decision diagram compilation
• FixedWidth – limits the decision diagram width

Search Configuration

• Search strategy: Large Neighborhood Search (LNS)
• Time limit: 10,000 milliseconds (10 seconds)
• Width heuristic: fixed width of 1,000 nodes per layer

Output

The program prints:

• Intermediate solutions during the search
• Final solution statistics
• The best sequence of pick-ups and deliveries found

See Also:

• PDPProblem
• PDPState
• PDPFastLowerBound
• PDPRanking
• LnsModel
• Solvers.minimizeLns(org.ddolib.modeling.LnsModel<T>, java.util.function.Predicate<org.ddolib.common.solver.SearchStatistics>, java.util.function.BiConsumer<int[], org.ddolib.common.solver.SearchStatistics>)
• Solution

Constructor Summary

Constructors

Constructor	Description
PDPLnsMain()

Method Summary

Modifier and Type	Method	Description
static void	main(String[] args)	Main entry point of the program.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

PDPLnsMain

public PDPLnsMain()

Method Details

main

public static void main(String[] args)
                 throws IOException

Main entry point of the program.

Generates a PDP instance, configures the LNS model with problem-specific heuristics, and runs the optimization process.

Parameters:

args - command-line arguments (currently unused)

Throws:

IOException - if any file access occurs (not used here but for consistency)