Introduction
Porta was written at theUniversity of Heidelberg to analyze polytopes and
polyhedra.
Convex objects are represented in one of two ways:
- ieq files
- namely, lists of inequalities and equalities.
- poi files
- namely, lists of points whose convex hull and convex cone describe
the object.
Using Porta
The most basic usage of the program is conversion between these two formats.
Use of the verbose option -v also reports the face-vertex incidence structure.
Porta is installed on the mathlab linux machines utah and tahoe,
in the directory /local/porta.1.3.1. It is also installed on math.cornell.edu in the directory /usr/local_sol/porta. (The subdirectory
man1 has man pages.)
For example, if one wishes to work with the cube of side 2 in 4 dimensions:
- traf -v cube4.ieq
- produces the file cube4.ieq.poi
- traf -v cube4.poi
- produces the file cube4.poi.ieq
The release also comes with files example.ieq and example.poi which illustrate other aspects of the format of data files.
Local Man Pages From Porta 1.3.1
- dim - compute the dimension of convex hull and convex cone for a set of given points
- fctp - checks inequalities for facet-inducing property
- fmel - projection of linear system on subspaces
- ieq - format of '.ieq' - files
- iespo - enumeration of equations and inequalities that are valid for a convex cone and a convex hull
- poi - format of '.poi' - files
- poiieq - format of '.poi' - files
- porta - introduction to the program
- portsort - sort inequalities or point systems
- posie - enumeration of points that are valid for a linear system
- traf - transformation of polyhedral representations
- vint - enumeration of integral linear points of a linear system
Last Update: June 24, 1997