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KnapScal

ScalaFX didactic application for the Knapsack problem

Introduction

KnapScal is a didactic ScalaFX application dedicated to the Knapsack problem.

It can solve an instance of the problem by employing different techniques:

• KP01 Branch & Bound - with a few standard functions for computing the upper bound of nodes. In particular:

  • Dantzig
  • Optimized Dantzig
  • Martello-Toth

• KP01 Dynamic Programming - keeping track of both active and dominated states

• Optimized Dynamic programming - using recursive functions to compute just the value of the solution

As shown in the screenshots below, the latest version of the application employs the EighthBridge library to actually render the Knapsack tree in a Branch and Bound solution!

Requirements

KnapScal requires Java 8 Update 91 or later compatible version.

Running KnapScal

The suggested way to run KnapScal is MoonDeploy, as it will automatically download and launch the application - just go to the latest release page and open the file App.moondeploy.

Otherwise, to start the application:

1. Download and decompress the zip archive
2. Run the file bin/KnapScal (on UNIX) or bin/KnapScal.bat (on Windows)

Users already having KnapScal can just run the program: MoonDeploy will automatically update it to KnapScal 2

Branch & Bound solution

KnapScal now renders the Branch & Bound solution as a tree, just as expected.

Zooming and panning

• To zoom in/out, use the mouse wheel

• To pan, press SHIFT and, while holding it, drag any point of the drawing

Laying out the nodes

Starting from version 3, KnapScal automatically lays out the tree nodes; however, should you notice overlapping nodes, you can drag & drop the nodes in the tree itself, to reposition them

Employing the kernel

KnapScal-core, the underlying library, can be used in other applications for the JVM.

Screenshots

Special thanks

Special thanks to Professor Silvano Martello for his valuable advice and suggestions.

Further references

• EighthBridge - Interactive graph modeling and rendering for ScalaFX

• KnapScal-core - Scala library for the Knapsack problem

• Professor Silvano Martello - Didactic slides

• Knapsack Problems - complete book, free to download! ^__^