We have the pleasure to announce the release 0.4.2 of the Parma Polyhedra Library, a minor bugfix release. Most of the bugs fixed in this release were discovered thanks to the ongoing effort to extend the PPL test suite so as to cover 100% of the library's code.

For more information, visit the PPL web site at

http://www.cs.unipr.it/ppl/

The PPL development team:

Roberto Bagnara bagnara@cs.unipr.it Patricia M. Hill hill@comp.leeds.ac.uk Elisa Ricci ericci@cs.unipr.it Enea Zaffanella zaffanella@cs.unipr.it

Bugfixes ========

o Fixed a bug in method Polyhedron::add_generator(const Generator&) whereby we were not adding the corresponding closure point when adding a point to an empty NNC polyhedron.

o Fixed a bug in method GenSys::insert(const Generator&) whereby the insertion of a generator into an empty generator system might be mishandled.

o Fixed a bug in method Polyhedron::operator<=(const Polyehdron&) whereby the lines of the polyhedron were handled improperly.

o Fixed a bug in a private method used to implement public method Polyhedron::relation_with(const Generator& g), whereby a wrong result was obtained when `g' was a line.

o Fixed a bug in methods Polyhedron::affine_image() and Polyhedron::affine_preimage(), whereby a wrong result could be obtained when using a negative denominator for the affine expression.

o Fixed a bug in methods Polyhedron::minimized_constraints() and Polyhedron::minimized_generators(), whereby a library invariant was violated when calling these methods on a zero-dimensional space universe NNC polyhedron.