GeoCalcLib: An interface for David Avis' LRS library

GeoCalcLib is an interface to lrs and redund developed by Rainer Schaich. For the original repository and website, see http://worc4021.github.io/GeoCalcLib. This fork serves to provide detailed installation instructions and possible improvements to this repository.

What does GeoCalcLib do?

The geometric calculation library uses David Avis' LRS library, to compute the vertex enumeration of a polyhedral set P = {x: A*x<=b}. It also computes the facet enumeration to P = conv(V) + cone(R). It has a function to compute the projection of a polyhedron, as well as reduction functions to obtain minimal representations of both V and H-representations of polyhedra.

Installation

Requirements

• MATLAB (Tested with R2018b, 2020a)
• Requires GMP library and gcc, make, m4.

  ⚠️ MATLAB may complain that it found a version of gcc that is not in its list of supported compilers https://www.mathworks.com/support/requirements/supported-compilers.html. Ignoring this warning has not proved to be fatal yet! We were able to get MATLAB R2020a accept gcc-5.5 version as well.

Linux/MacOS

Your standard gcc should have GMP installed. Else, see the instructions in troubleshooting below.

1. Download a zip file of this repository OR clone this repository using

   git clone https://github.com/sreachtools/GeoCalcLib
   

2. Edit User.make file to include the path to MATLAB root folder.
   • Note that <FULL-PATH-TO-YOUR-MATLAB-INSTALLATION> is the parent directory of MATLAB bin folder and does not end with a /.
   • Run in MATLAB command prompt

     matlabroot
     

     See https://www.mathworks.com/matlabcentral/answers/66570-what-is-the-default-installation-path-for-matlab-on-architecture-x#answer_78163 for more details
3. Run in MATLAB command prompt

   mex -v -setup
   

   to make sure that that MATLAB's mex knows where gcc is.
4. Run in Unix command prompt after changing directory to the GeoCalcLib folder,

   make
   

5. Add /path/to/GeoCalcLib/mexfiles to MATLAB path. If you want to use this across sessions, we recommend adding the following command to your MATLAB startup.

   addpath('/path/to/GeoCalcLib/mexfiles');
   

Troubleshooting: GMP installation

Issue: make fails to find gmp.h

Solution: Install GMP --- a free library for arbitrary precision arithmetic, operating on signed integers, rational numbers, and floating-point numbers.

Steps: Build GMP from sources. (Last tested on gmp-6.2.0.tar.lz)

1. Get the tar ball from https://gmplib.org/#DOWNLOAD
2. Follow the installation instructions https://gmplib.org/manual/Installing-GMP.html#Installing-GMP
   1. Run ./configure in the folder containing the extracted gmp files.
   2. Run make
   3. Run sudo make install to add the files.

Windows

A major issue is the LRS's requirement of GMP. If anyone figures out how to jump that hoop, please let me know.