andern / pplex Goto Github PK

a pedagogical implementation of the Simplex method

Home Page: http://andern.github.com/pplex

License: GNU General Public License v3.0

TeX 15.66% Java 78.69% GAP 5.65%

pplex's Introduction

About

pplex is an application that can interpret linear programs (LP) and show how the LP dictionary evolves throughout the execution of the simplex method.

pplex is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

pplex uses Apache Commons Math library for handling matrices. It is released under the Apache License, Version 2.0. See lib/LICENSE.TXT for more information.

Try the pplex applet!

Documentation

Documentation on how to use pplex can be found here.

Reporting Bugs

GitHub's issue tracker is used for tracking bugs of pplex. Before submitting a bug you should make sure that you are running the latest version of pplex, and that the bug has not already been submitted to the tracker on GitHub.

Installing pplex

If you want to try pplex before installing it, you can try it as an applet by visiting http://pplex.ii.uib.no. It has most of the functionality of pplex (but you cannot read your own files.)

Running pplex requires Java Runtime Environment installed on your computer.

Download the newest version of pplex from one of the links above.
Extract the archive.
Double-click on pplex.jar.
(Getting started) Type read input/vdb2.8.lps in pplex' console.

Running pplex

pplex starts in visual mode by default. This is only relevant for linear programs with two variables. pplex can easily be run without a graphical interface in a terminal window by passing the '-nogui' argument like this: java -jar pplex.jar -nogui

Compiling pplex

Compiling pplex requires:

Java Development Kit
Apache Ant

To compile pplex you first need to download the source code of pplex. This can be done from the website or by cloning the repository.

To clone the repository you need git installed on your system. Cloning the repository is done by typing the following in a terminal: git clone [email protected]:andern/pplex.git

To only compile the sources of pplex, run ant compile in the pplex directory.

To compile the sources of pplex and build a runnable jar, run ant jar or simply ant

Applet

pplex can be compiled as an applet by running ant applet in the pplex directory.

See applet.html in the pplex directory for an example on how to deploy the applet on your own website.

pplex's People

Contributors

Stargazers

Watchers

Forkers

joannabauer haitech bewithjitendrapatel shirinfa jht1983 rinskyx2

pplex's Issues

shading bug

read input/vdb2.8.lps shows some irregularities in the coloring of the convex polygon

Tab-completion

When in CLI, it should be possible with tab-completion.

gui works fine with more var's, but doesn't scroll after show

f.e. after read input/nik5.pls, show etc.

Add possibility to show command history longer than the last ten.

For example:

log 11

shows the last 11 commands.

read command cannot read files with empty lines

Found by marcbezem:

lpped> read file
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1
at controller.Parser.parse(Unknown Source)
at controller.CLI.parseRead(Unknown Source)
at controller.CLI.parseCmd(Unknown Source)
at controller.CLI.run(Unknown Source)
at controller.Main.main(Unknown Source)

file has an empty line at the end.

OutOfMemoryError when image (for exporting to png) size is too large.

I actually did not choose a very large image size when this happened, but my cpu usage was 100%.
Stack trace:

Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
    at java.awt.image.DataBufferInt.<init>(DataBufferInt.java:41)
    at java.awt.image.Raster.createPackedRaster(Raster.java:458)
    at java.awt.image.DirectColorModel.createCompatibleWritableRaster(DirectColorModel.java:1015)
    at java.awt.image.BufferedImage.<init>(BufferedImage.java:324)
    at controller.Screenshot.screenshot(Unknown Source)
    at controller.Screenshot.actionPerformed(Unknown Source)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2028)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2351)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
    at java.awt.Component.processMouseEvent(Component.java:6382)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3275)
    at java.awt.Component.processEvent(Component.java:6147)
    at java.awt.Container.processEvent(Container.java:2083)
    at java.awt.Component.dispatchEventImpl(Component.java:4744)
    at java.awt.Container.dispatchEventImpl(Container.java:2141)
    at java.awt.Component.dispatchEvent(Component.java:4572)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4619)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4280)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4210)
    at java.awt.Container.dispatchEventImpl(Container.java:2127)
    at java.awt.Window.dispatchEventImpl(Window.java:2489)
    at java.awt.Component.dispatchEvent(Component.java:4572)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:704)
    at java.awt.EventQueue.access$400(EventQueue.java:82)
    at java.awt.EventQueue$2.run(EventQueue.java:663)
    at java.awt.EventQueue$2.run(EventQueue.java:661)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
    at java.awt.EventQueue$3.run(EventQueue.java:677)

Serious bug

The .jar file currently throws exceptions

bug in the pivoting algorithm

read input/vdb2.8.lps brings a bug to the surface, after pivot 2 8 and then pivot, pivot, ... a singular matrix occurs where it shouldn't

Unnecessary + sign shown in first column if non-basic variable is equal to 0.

lpped> show primal
 ζ =      + 6.00x1 + 8.00x2 + 5.00x3 + 9.00x4
w1 = 5.00 - 2.00x1 -     x2 -     x3 - 3.00x4
w2 = 3.00 -     x1 - 3.00x2 -     x3 - 2.00x4

The + in front of 6.00x1 is unnecessary and should be removed.

Pathnames

Windows denotes paths with \ instead of /. The \ shows up after the command read inp/... confusing some users.

Parser issues with the examples below

maximize 0
subject to
2x +        y + 2z <= 2
      3x' + y - 2z <= 0
          - y      <= -1

gives empty objective function, error message: line 2:0 missing VARNAME at 'subject to', but "OK"

maximize 1
subject to
2x +        y + 2z <= 2
      3x' + y - 2z <= 0
          - y      <= -1

gives objective + , error message, plus "Read input/intsat2.lps OK." and all indices of var's are incremented

maximize 1
subject to
x + y + 2z <= 2
x + y - 2z <= 0
    - y      <= -1

gives error messages (and is not "OK"):
line 2:0 extraneous input 'subject to' expecting VARNAME
line 3:11 mismatched input '<=' expecting CONSTRAINTSSECTION
in pplex window: read: Error reading file: matrix must have at least one row

Also this one is not OK:

maximize 1
subject to x + y + 2z <= 2
           x + y - 2z <= 0
             - y      <= -1

It is useful to be able to use constant objective functions (feasibility only)

Code cleanup: Split the toString()-method in Matrix.java into multiple methods.

As the title says.

Add possibility to undo/redo more than one command at a time.

For example

undo 20

undoes the last 20 commands. And

redo 20

redoes last 20 undone commands.

program crashes with unknown source on certain files

reproduce: read input/nik6.lps

[critical] Program crashes when reading files with coefficient 0 (implicitly) in the objective function.

Reproducable with the following file:

max          2x1 - 6x2
subject to  - x1 -  x2 - x3 <= -2
             2x1 -  x2 + x3 <= 1

A workaround for this before it is fixed is to explicitly state the 0 coefficient like this:

max          2x1 - 6x2 + 0x3 
subject to  - x1 -  x2 -  x3 <= -2
             2x1 -  x2 +  x3 <= 1