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Dylp

Overview

dylp is an implementation of the dynamic simplex algorithm. Briefly, dynamic simplex attempts to work with an active constraint system which is a subset of the full constraint system. It alternates between primal and dual simplex phases. Between simplex phases, it deactivates variables and constraints which are not currently useful, and scans the full constraint system to activate variables and constraints which have become useful. The dylp documentation describes dylp's algorithms in detail.

dylp is intended as a development code. The implementation puts more weight on clarity than efficiency and is heavily instrumented and commented. It can be built with extensive statistics, informational printing, and consistency checks. It can also be built without any of these. Fully optimised, it's decently fast.

dylp is a C code, and can be used in a pure C environment completely independent of other COIN software. It also has a COIN-OR OSI interface, OsiDylp, which takes advantage of capabilities provided by COIN (e.g., enhanced input/output and constraint system preprocessing) and is recommended if you're working in a C++ environment.

dylp is released as open source under the Eclipse Public License 2.0.

It is distributed under the auspices of the COIN-OR Foundation

dylp is not under active development. The source repository is https://github.com/coin-or/DyLP. In summer 2022 it was upgraded to conform to COIN GitHub repository standards current at the time.

Current Build Status

Download, Configuration, and Testing

dylp has no current releases. Clone the git repository and use the master branch. You can use coinbrew to automate the process of cloning the repositories for dylp and its dependencies and building the software. This is the best way to get started. If you want to build in a separate directory from the source files, use the coinbrew option --build-dir. If you want to install in a specified directory, use the coinbrew option --prefix.

Once you have created the necessary repositories, the minimal action required for configuration and build is to run the commands

./configure
make

in the top level directory of the distribution. Run

./configure --help

for a list of available configuration options. If you're building in a directory separate from the source directory, run configure and make from the build directory as

cd /path/to/build/Dylp
path/to/src/Dylp/configure
make

To install in a specified directory, use the --prefix option to configure as

path/to/src/Dylp/configure --prefix /path/to/install
make
make install

For a test of correct installation, dylp runs its own unit test and the OsiDylp unit test. Simply type the command

make test

in the top level build directory to build and run the unit tests.

Examples

The dylp distribution also provides two simple main programs in the directory DyLP/examples. Be sure to execute the command

make install

in the top level build directory before attempting to build the examples! To build the examples, change directory to DyLP/examples and execute the command

make examples

A simple shell script, plain, provides a convenient wrapper for both main programs. Execute the command 'plain --help' for usage information.

Dependencies

dylp's dependencies are specified in the config.yml file used by coinbrew and in the (semi-obsolete) Dependencies file. The master branch is specified but the latest releases should be entirely sufficient.

Bugs

There are undoubtably a few left somewhere. If you run across one, please let us know. The preferred way is to use a issue. You can browse existing issues to see if your bug has already been reported and add additional information. Otherwise, please submit a new issue.