Parma Polyhedra Library NEWS -- history of user-visible changes =============================================================== -------------------------------------------------------------------------- NEWS for version 0.8 (released on January 20, 2006) -------------------------------------------------------------------------- New and Changed Features ======================== o The class template BD_Shape provides an implementation of the abstract domain of bounded difference shapes. The template type parameter T specifies the basic type used for the inhomogeneous term of bounded difference constraints; it can be instantiated to either GMP's unbounded precision types (mpq_class, mpz_class), native floating point types (float, double), or native integer types (8, 16, 32 and 64 bits wide). o New class LP_Problem provides an implementation of the primal simplex algorithm using exact arithmetic. o The new program `ppl-config' returns information about the configuration and the installed components of the PPL. This greatly simplifies the task of writing makefiles and automatic configuration scripts. A manual page for `ppl-config' has also been added. o New Autoconf function AM_PATH_PPL([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]]) allows to test the existence and usability of particular versions of the PPL, defining macros containing the required paths. The simple addition of, e.g., AM_PATH_PPL(0.8) to an application's configure.ac file is all that is needed in most cases. Paths to the installed version of the PPL will be detected, the version number will be checked to be at least the one indicated, the variables PPL_CPPFLAGS and PPL_LDFLAGS will be set accordingly and a quick sanity check of the PPL installation will be performed. For more complex tasks, the AM_PATH_PPL function defines the `--with-ppl-prefix' and `--with-ppl-exec-prefix' configure options (useful when the PPL is installed into a non-standard place or when multiple versions of the PPL are installed). AM_PATH_PPL also defines the `--disable-ppltest' configure option to disable the quick sanity check. When something fails, AM_PATH_PPL provides accurate indications about what went wrong and how to fix it. See the sources in m4/ppl.m4 for more information. o The browse and print versions of the PS and PDF formats of the user manual have been merged into single documents: ppl-user-0.8.pdf and ppl-user-0.8.ps.gz. The equivalent developer reference documents have also been merged. o One of the possible values for the configuration option `--enable-coefficients' has been renamed from `gmp' to `mpz'. o New configuration option `--enable-interfaces' allows some or all of the Prolog and C interfaces to be selectively enabled. o Portability has been further improved. o Added to C_Polyhedron (resp., NNC_Polyhedron) new method bool poly_hull_assign_if_exact(const C_Polyhedron&) (resp. bool poly_hull_assign_if_exact(const NNC_Polyhedron&)) and its synonym bool upper_bound_assign_if_exact(const C_Polyhedron&) (resp. bool upper_bound_assign_if_exact(const NNC_Polyhedron&)). o Added new typedef `element_type' to template Polyhedra_Powerset, which corresponds to the type of the underlying numeric domain. o Output operators have been added for Generator::Type and Constraint::Type. o Class Bounding_Box has new method Constraint_System Bounding_Box::constraints() const, which returns the system of constraints. o Class Bounding_Box has new widening methods Bounding_Box::CC76_widening_assign(const Bounding_Box& y) and template Bounding_Box::CC76_widening_assign(const Bounding_Box& y, Iterator first, Iterator last). o All methods in class Determinate that are specific to the Polyhedra template parameter have been dropped. If needed, they can still be invoked through element(). o Method bool Constraint_System::has_strict_inequalities() const is now publicly accessible. o Added Polyhedron methods difference_assign() and join_assign(), behaving as poly_difference_assign() and poly_hull_assign(), so as to have more uniform interfaces. o The helper function widen_fun_ref() building a limited widening function is now templatic even on the second argument (i.e., the limiting constraint system). The templatic widening method Polyhedra_Powerset::BHZ03_widening_assign() no longer has a default value for the certificate parameter. o The signatures of Polyhedron methods maximize() and minimize() have been greatly simplified. o The function template template bool check_containment(const PH&, const Polyhedra_Powerset&) now works whenever there exists a lossless conversion mapping an object of type PH into an NNC_Polyhedron (e.g., when PH = BD_Shape). The same holds for methods bool Polyhedra_Powerset::geometrically_covers() and bool Polyhedra_Powerset::geometrically_equals(). o Disjuncts can be added to an instance of Polyhedra_Powerset with the new method void add_disjunct(const PH& ph). o The two generalized_affine_image() methods of class Polyhedron are now matched by corresponding methods for computing preimages of affine relations. o Added to class Polyhedron the method void bounded_affine_image(Variable v, const Linear_Expression& lb, const Linear_Expression& ub, Coefficient_traits::const_reference d = Coefficient_one()) computing the image of the polyhedron according to the transfer relation lb/d <= v' <= ub/d. Also added the corresponding method for computing preimages. o The enumeration Polyhedron::Degenerate_Kind has been placed outside of class Polyhedron and renamed as Degenerate_Element. o New output operators in namespace IO_Operators: std::ostream& operator<<(std::ostream&, const Constraint::Type&) and std::ostream& operator<<(std::ostream&, const Generator::Type&). o Added to class Constraint the methods bool is_tautological() const and bool is_inconsistent() const returning true when the constraint is always or never satisfied, respectively. o Added to classes Constraint (resp., Generator) the method bool is_equivalent_to(const Constraint& y) const (resp., bool is_equivalent_to(const Generator& y) const) which check for semantic equivalence of corresponding class instances. Also made available the (semantic) comparison operators `==' and `!='. o The swap() methods of classes Linear_Expression, Constraint, Generator, Constraint_System and Generator_System are now publicly accessible. o Added to classes Constraint and Generator the methods void ascii_dump(std::ostream& s) const and void ascii_load(std::istream& s) const. o In classes Poly_Con_Relation and Poly_Gen_Relation the methods void ascii_dump(std::ostream& s) const and void ascii_load(std::istream& s) const are now publicly accessible. o All classes which provide the method void ascii_dump(std::ostream& s) const now also provide the methods void ascii_dump() const and void print() const. These methods print to std::cerr the textual and user-level representation (resp.) of the given object. This enables the output of such object representations in GDB. o New functions added to the C interface: int ppl_Coefficient_is_bounded(void), int ppl_Coefficient_min(mpz_t min), int ppl_Coefficient_max(mpz_t max) allow C applications to obtain information about the Coefficient integer numerical type. The new Prolog interface predicates ppl_Coeffient_is_bounded/0, ppl_Coefficient_max/1 and ppl_Coefficient_min/1 provide the same functionality. o All predicates in the Prolog interface that require an input list as an argument will now throw an exception if that argument is not a list. Before, some predicates, such as ppl_Polyhedron_remove_space_dimensions/2, would fail. o In the Prolog interface, the names and arities of the "with_token" widening and extrapolation predicates have been revised to "with_tokens" with an extra argument and the functionality has been revised to match more closely the corresponding C++ interface operators. o In the Prolog interface, the names and arities of the predicates that create handles for new polyhedra have been revised to match more closely the corresponding C and C++ interface operators. That is, instead of having "c" and/or "nnc" as arguments to indicate the topology of the polyhedron, the topologies are now part of the names of the predicates. o The SWI-Prolog interface allows now the exchange of unbounded numbers between the PPL and Prolog applications. This requires SWI-Prolog version 5.6.0 or later version. Previous versions of SWI-Prolog are no longer supported. o The YAP interface allows now the exchange of unbounded numbers between the PPL and Prolog applications. This requires YAP version 5.1.0 or later version. Previous versions of YAP are no longer supported. o The `ppl_lpsol' demo has now two more options: with `--enumerate' it solves the given linear programming problem by vertex/point enumeration; with `--simplex' (the default) it uses our simplex implementation with exact arithmetic. The `ppl_lpsol' program, which is only built if a suitable version of GLPK is available, is installed into the directory (selectable at configuration time) for user executables. o Manual pages have been added for the ppl_lpsol and ppl_lcdd programs. o The new class BD_Shape as well as the "checked" native coefficients selectable with the `--enable-coefficients' configure options, are based on a very general and powerful notion of "number family with a policy". This is made available to the users of the PPL via the wrapper template class Checked_Number, where T is the underlying numeric type (native integer or float of any width, unbounded integer or rational) and `P' is a policy specifying things such as whether to check for overflows and other "exceptional" conditions and what to do in such cases. The policy also specifies whether T should be extended with representations for infinities or NAN (Not A Number) and default rounding modes. A complete set of arithmetic functions and operators are provided: they either use the default rounding mode or accept a rounding mode as an extra parameter and, depending on the policy, may return a result that indicates the relation that exists between the true mathematical result and the (possibly approximate) computed result. Input/output functions with the same properties (controlled rounding and indications of the approximations) are also provided. Bugfixes ======== o Fixed a bug in Polyhedra_Powerset::concatenate_assign() whereby a temporary Polyhedra_Powerset object was created with the wrong dimension. o Corrected a memory leak bug in the demo ppl_lpsol. o Corrected a bug in method NNC_Polyhedron::minimized_constraints() whereby an internal assertion might have been violated. o Fixed a bug whereby calling the methods Polyhedron::generalized_affine_image() on an empty polyhedron could have resulted in an exception thrown. o Fixed a bug whereby the occurrence of an `out of memory' error during the allocation of a row of integer coefficients could have resulted in a memory leak. o Fixed a bug affecting the specialized constructors Polyhedra_Powerset:: Polyhedra_Powerset(const Polyhedra_Powerset& y) and Polyhedra_Powerset:: Polyhedra_Powerset(const Polyhedra_Powerset& y) whereby the newly built Polyhedra_Powerset object could have been flagged as non-redundant even though it was containing redundant disjuncts. Fixed a similar bug in generic constructor Polyhedra_Powerset(const Constraint_System& cs) that manifests when `cs' is denoting an empty polyhedron. -------------------------------------------------------------------------- NEWS for version 0.7 (released on December 24, 2004) -------------------------------------------------------------------------- New and Changed Features ======================== o The new configuration option `--enable-coefficients' allows for the use of alternative (integral) coefficient types. Besides GMP integers, the user can now use checked native integers (8, 16, 32 or 64 bits wide). The use of such native coefficients is completely safe, since systematic (yet efficient) overflow detection is performed and, in case of overflow, an exception is raised. GMP coefficients are used by default. o Significant efficiency improvements have been achieved everywhere. o We now require GMP 4.1.3 or higher. o The following classes have been renamed as indicated: AskTell -> Ask_Tell BoundingBox -> Bounding_Box ConSys -> Constraint_System GenSys -> Generator_System Integer -> Coefficient LinExpression -> Linear_Expression Polyhedra_PowerSet -> Polyhedra_Powerset PowerSet -> Powerset SatMatrix -> Saturation_Matrix SatRow -> Saturation_Row o The helper function `widen_fun' has been renamed `widen_fun_ref'. o New assignment operators allowing to obtain an NNC_Polyhedron from a C_Polyhedron and the other way around. In the latter case, the topological closure of the argument polyhedron is computed. o New explicit constructors and assignment operators allowing to obtain a Polyhedra_Powerset from a Polyhedra_Powerset and the other way around. In the latter case, the topological closure of the element polyhedra is computed. o New explicit constructor Powerset::Powerset(const CS& d): if `d' is not bottom, builds a powerset containing only `d'; builds the empty powerset otherwise. o New explicit constructor Polyhedra_Powerset::Polyhedra_Powerset(const PH& ph): if `ph' is not empty, builds a powerset containing only `ph'; builds the empty powerset otherwise. o New method Polyhedra_Powerset::poly_difference_assign(const Polyhedra_Powerset& y) assigns to `*this' the poly-difference of `*this' and `y'. o All the public classes of the library have been endowed with methods memory_size_type total_memory_in_bytes() const and memory_size_type external_memory_in_bytes() const returning (lower bounds for) the total size in bytes of the memory occupied by *this and of the memory managed by *this, respectively. The type `memory_size_type' is a newly added unsigned integral type suitable to the representation of such information. o New method dimension_type Polyhedron::affine_dimension() returns the affine dimension of *this (not to be confused with the dimension of its enclosing vector space) or 0, if *this is empty. o All the methods changing (i.e., adding, removing, mapping, etc.) the dimensions of the vector space have been renamed so as to avoid any possible ambiguity with the affine dimension of the modified object. For instance, Polyhedron::add_dimensions_and_embed(dimension_type m); has been renamed as Polyhedron::add_space_dimensions_and_embed(dimension_type m); o The constructor C_Polyhedron(const NNC_Polyhedron& y) no longer throws an exception if `y' is not topologically closed. Rather, it constructs a C_Polyhedron representing the topological closure of `y'. o The following constructors have been made explicit: Constraint_System::Constraint_System(const Constraint& c), Generator_System::Generator_System(const Generator& g), C_Polyhedron::C_Polyhedron(const Constraint_System& cs), C_Polyhedron::C_Polyhedron(const Generator_System& cs), C_Polyhedron::C_Polyhedron(Constraint_System& cs), C_Polyhedron::C_Polyhedron(Generator_System& cs), NNC_Polyhedron::NNC_Polyhedron(const Constraint_System& cs), NNC_Polyhedron::NNC_Polyhedron(const Generator_System& cs), NNC_Polyhedron::NNC_Polyhedron(Constraint_System& cs), NNC_Polyhedron::NNC_Polyhedron(Generator_System& cs). Polyhedra_Powerset::Polyhedra_Powerset(const Constraint_System& cs). o Functions in the C interface that compute (space) dimensions no longer return their result. The caller is now required to pass, as an extra argument, a pointer to a memory area where the result will be written. All the C interface functions now use the return value to signal the success or failure of the requested operation. o Now `make check' runs a number of tests with `ppl_lcdd', comparing the results to expected ones. o The `ppl_lcdd' demo is now able to parse problems produced by lrs, i.e., where the number of rows of the matrix is omitted and replaced by "*****" (five asterisks). o The enumeration values of enum Complexity_Class have been renamed POLYNOMIAL_COMPLEXITY, SIMPLEX_COMPLEXITY and ANY_COMPLEXITY. o In the Prolog interface, the predicates ppl_new_polyhedron_from_dimension/3 and ppl_new_polyhedron_empty_from_dimension/3 have been replaced by a single predicate ppl_new_polyhedron_from_space_dimension/4 where the (extra) third argument indicates whether the polyhedron to be created should be the universe or the empty polyhedron. o As the unary plus operator is not in standard Prolog, '+'/1 in linear expressions is no longer supported by the Prolog interface. Bugfixes ======== o Fixed a bug that was causing an unwanted exception to be thrown when adding to a C_Polyhedron some generators obtained from an NNC_Polyhedron (even though no closure point was being added). o Fixed a bug in the handling of empty generator systems having a strictly positive space dimension. o Fixed a bug that was affecting Polyhedra_PowerSet::geometrically_covers() and Polyhedra_PowerSet::geometrically_equals(). o Method C_Polyhedron::H79_widening_assign() now widens the polyhedron itself instead of the homogenized polyhedral cone representing it. o Fixed a bug that was affecting Polyhedron::H79_widening_assign() as well as all the limited and bounded extrapolation operators. o Fixed a bug in Polyhedron::map_space_dimensions() that could manifest itself when used with a partial function encoding permutation. o Fixed a bug in the C interface function ppl_new_Linear_Expression_with_dimension(). o Fixed a bug in the `ppl_lpsol' demo. o Fixed a bug in Polyhedron::is_universe() that could manifest itself when the polyhedron is described by a generator system that is not in minimal form. -------------------------------------------------------------------------- NEWS for version 0.6.1 (released on August 20, 2004) -------------------------------------------------------------------------- New and Changed Features ======================== o Some packaging issues have been fixed. o The documentation has been completed and improved. o The methods Polyhedra_PowerSet::semantically_contains(const Polyhedra_PowerSet&) and Polyhedra_PowerSet::semantically_equals(const Polyhedra_PowerSet&) have been renamed Polyhedra_PowerSet::geometrically_covers(const Polyhedra_PowerSet&) and Polyhedra_PowerSet::geometrically_equals(const Polyhedra_PowerSet& y), respectively. -------------------------------------------------------------------------- NEWS for version 0.6 (released on August 18, 2004) -------------------------------------------------------------------------- New and Changed Features ======================== o New templatic classes Determinate, PowerSet, and Polyhedra_PowerSet. The first two classes realize, in a completely generic way, the determinate and powerset constructions described by Roberto Bagnara in his 1998, Science of Computer Programming paper. The third class is a specialization of the powerset construction on polyhedra. The powerset construction comes with the generic widening technique proposed by Roberto Bagnara, Patricia Hill and Enea Zaffanella in their VMCAI 2004 paper. Actually, the Polyhedra_PowerSet class provides the first genuine, non-trivial widening ever proposed (let alone made available) on a domain of sets of convex polyhedra. o New methods void Polyhedron::expand_dimension(Variable, dimension_type) and void Polyhedron::fold_dimensions(const Variables_Set&, Variable) allow the easy realization of summary dimensions as proposed by Denis Gopan and colleagues in their TACAS 2004 paper. o A new `demos' directory has been added. In the `ppl_lcdd' subdirectory, this contains a sort of clone of the cddlib test program `lcdd', written using the PPL's C++ interface, together with several example polyhedra in the formats that the program can handle. The `ppl_lpsol' subdirectory contains another demo program that solves linear programming problems by vertex/point enumeration. This is written using the PPL's C interface and comes with several example problems in the Mathematical Programming System (MPS) format. In order to read MPS files, `ppl_lpsol' uses the GNU Linear Programming Kit (GLPK); thus `ppl_lpsol' is only compiled if a suitable version of GLPK is available. o New macro PPL_VERSION expands to the version string of the library. o New file README.configure provides additional information about the configuration and compilation of the library. o The documentation has been improved in various ways. o The documentation for users, in PostScript, PDF and HTML formats, is now installed in a standard place by `make install'. o The variable `abandon_exponential_computations' has been renamed `abandon_expensive_computations'. o The methods void Polyhedron::add_constraints(ConSys& cs), void Polyhedron::add_generators(GenSys& gs), bool Polyhedron::add_constraints_and_minimize(ConSys& cs), and bool Polyhedron::add_generators_and_minimize(GenSys& gs) have been renamed void Polyhedron::add_recycled_constraints(ConSys& cs), void Polyhedron::add_recycled_generators(GenSys& gs), bool Polyhedron::add_recycled_constraints_and_minimize(ConSys& cs), and bool Polyhedron::add_recycled_generators_and_minimize(GenSys& gs), respectively. At the same time, the methods void Polyhedron::add_constraints(const ConSys& cs), void Polyhedron::add_generators(const GenSys& gs), bool Polyhedron::add_constraints_and_minimize(const ConSys& cs), and bool Polyhedron::add_generators_and_minimize(const GenSys& gs) have been added. Corresponding changes have been made to the C and Prolog interfaces. o New methods Polyhedron::maximize() and Polyhedron::minimize() for maximizing and minimizing a linear expression subject to the polyhedron. o New output operator in namespace IO_Operators: std::ostream& operator<<(std::ostream&, const LinExpression&). o The method Polyhedron::map_dimensions(const PartialFunction& pfunc) has been significantly optimized for the case when `pfunc' is a permutation. A simple "renaming" of the dimensions is now extremely cheap. o The function Parma_Polyhedra_Library::max_space_dimension() has been given a new semantics and destiny: it returns the maximum space dimension that _all_ the abstractions provided by the library can handle. Each individual abstraction provides its versions of this function. Thus, e.g., NNC_Polyhedron::max_space_dimension() gives the maximum space dimensions an NNC_Polyhedron can handle. o The type of output functions for the class Variable, `Variable::Output_Function_Type', has been renamed `Variable::output_function_type' and is now defined as void output_function_type(std::ostream& s, const Variable& v). In other words, `v' is now passed by const reference and not by value. o Thanks to Bruno Haible, it is now possible to use versions of the GMP library installed into nonstandard places. The new configure options --with-libgmp-prefix[=DIR] and --with-libgmpxx-prefix[=DIR] substitute the old (and not really working) options --with-gmp-includes=DIR and --with-gmp-dir=DIR. Bugfixes ======== o Fixed a bug in the C interface function ppl_Polyhedron_map_dimensions() whereby a wrong result was computed. o Fixed a bug in Polyhedron::poly_difference_assign(const Polyhedron&) whereby a wrong result was computed. o Fixed a bug in the Prolog interface predicate ppl_Polyhedron_get_bounding_box/3 whereby a wrong result was sometimes computed in the case of an empty polyhedron. o Fixed a bug in the Prolog interface predicate ppl_new_Polyhedron_from_bounding_box/3 whereby the predicate was failing when given an empty bounding box. -------------------------------------------------------------------------- NEWS for version 0.5 (released on April 28, 2003) -------------------------------------------------------------------------- New and Changed Features ======================== o New methods Polyhedron::BHRZ03_widening_assign() and Polyhedron::BHRZ03_limited_extrapolation_assign(). The BHRZ03 widening is a novel widening that is always more precise than the one, by now standard, we call H79. o The novel "widening with tokens" technique improves on the good old widening delay technique by refraining from widening only when necessary. Precision is thus increased still guaranteeing convergence. All widening operators can now be supplied with an optional argument, recording the number of available tokens, which is decremented when tokens are used. o Two new methods have been defined that compute the image of a polyhedron under an affine relation. The first method, Polyhedron::generalized_affine_image(var, relsym, expr, denom), generalizes the classical Polyhedron::affine_image() method by allowing `relsym' to denote any of the relations <, <=, =, >=, >. The second method, Polyhedron::generalized_affine_image(lhs, relsym, rhs), is a variant where an arbitrary linear expression `lhs' is allowed to occur on the left-hand side of the affine relation. o New constructors to build polyhedra from read-only constraint and generator systems: C_Polyhedron(const ConSys&), C_Polyhedron(const GenSys&), NNC_Polyhedron(const ConSys&), and NNC_Polyhedron(const GenSys&). In the C interface the functions taking non-const arguments named ppl_new__from_ have been renamed ppl_new__recycle_, where is either "C" or "NNC", and is either "ConSys" or "GenSys". The old names have been given to the new const functions. o New function LinExpression& operator*=(LinExpression&, const Integer&) to multiply (in place) an expression by a scalar. o The methods Polyhedron::check_empty() and Polyhedron::check_universe() have been renamed is_empty() and is_universe(), respectively. o New method bool Polyhedron::is_disjoint_from(const Polyhedron& y) returning true if and only `*this' and `y' are disjoint. o New methods bool Polyhedron::add_constraint_and_minimize(const Constraint&) and bool Polyhedron::add_generator_and_minimize(const Generator&) to add a constraint or a generator and minimizing the result at the same time. o New method: template void Polyhedron::map_dimensions(const PartialFunction&). This allows to rename the dimensions of a polyhedron according to a partial function mapping dimensions to dimensions. o New function LinExpression operator+(const LinExpression&): previously an expressions like `+x2-x3-x4 <= 0' could not constitute valid syntax for a constraint. o New type `dimension_type': an unsigned integral type for representing space dimensions. o New function dimension_type max_space_dimension(): returns the maximum space dimension this library can handle. o New function dimension_type not_a_dimension(): returns a value that does not designate a valid dimension. o The method Polyhedron::add_dimensions_and_constraints(ConSys&) has gone. A similar functionality is provided by the new method Polyhedron::concatenate_assign(const Polyhedron&). The same change has, of course, been performed on all the PPL interfaces. o New macros PPL_VERSION_MAJOR, PPL_VERSION_MINOR, PPL_VERSION_REVISION, and PPL_VERSION_BETA allow the client application to adapt to different versions of the library. o New function const char* version() returns a character string containing the PPL version. o New function const char* banner() returns a character string containing information about the PPL version, the licensing, the lack of any warranty whatsoever, the C++ compiler used to build the library, where to report bugs and where to look for further information. o The Prolog interface now supports also Ciao Prolog and XSB. o The C and Prolog interfaces have been extended so as to make more of the library's functionality available to Prolog and C users. o Timeout computation facilities have been added to the Prolog interfaces: new predicates ppl_set_timeout_exception_atom/1, ppl_timeout_exception_atom/1, ppl_set_timeout/1, ppl_reset_timeout/0. o Many efficiency improvements have been achieved. Part of these have been obtained by increasing the degree of "lazyness" of the library. o Many portability and standard-conformance improvements: the library can now be compiled with GNU g++, Intel C++ Compiler 7.0 for Linux, and Comeau C/C++ 4.3.0.1 Compiler Front-End; the library has also been tested on a variety of platforms. o The functions Polyhedron::operator<=(const Polyhedron&, const Polyhedron&), Polyhedron::operator>=(const Polyhedron&, const Polyhedron&), Polyhedron::operator<(const Polyhedron&, const Polyhedron&), and Polyhedron::operator>(const Polyhedron&, const Polyhedron&) have been removed. The methods Polyhedron::contains(const Polyhedron&) and Polyhedron::strictly_contains(const Polyhedron&) provide the same functionality. o The method Polyhedron::limited_H79_widening_assign() has been renamed Polyhedron::limited_H79_extrapolation_assign(). From now on, the name `widening' is reserved for operators that come with a convergence guarantee (i.e., with the ability of turning infinite chains to finite ones). Upper bound operators without such a guarantee contain the word `extrapolation' in their name. o The renamed method Polyhedron::limited_H79_extrapolation_assign() takes the constraint system argument by const reference (in the old Polyhedron::limited_H79_widening_assign() that argument was passed by non-const reference). o We now require GMP 4.1.2 or higher. o In conformance with the C++ standard [17.4.3.1.2], in all the identifiers exported by the C interface, any occurrence of "__" (double underscore) has been replaced by "_" (underscore). o Added a parameter to Polyhedron::shrink_bounding_box(): this specifies the complexity class of the algorithm to be used. o All the input/output operators have been confined into namespace Parma_Polyhedra_Library::IO_Operators. This way they do not conflict with the operators the user might want to define. o The operator Constraint operator>>(const Constraint&, unsigned int) has been removed. o The method Polyhedron::poly_difference_assign_and_minimize(const Polyhedron&) has been removed. Bugfixes ======== o Fixed a bug in operator-=(LinExpression&, const LinExpression&) whereby we computed a wrong result in some circumstances. o Fixed a bug in method Polyhedron::minimized_constraints() that, under some circumstances, could cause a wrong result or a program crash. -------------------------------------------------------------------------- NEWS for version 0.4.2 (released on October 4, 2002) -------------------------------------------------------------------------- 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 Polyhedron&) 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. -------------------------------------------------------------------------- NEWS for version 0.4.1 (released on July 30, 2002) -------------------------------------------------------------------------- Bugfixes ======== o Fixed a bug in Polyhedron::poly_difference_assign(const Polyhedron& y) whereby the equality constraints of `y' were ignored (the bug was affecting both C and NNC computations). o Fixed a bug in Polyhedron::operator=(const Polyhedron& y). This bug, which is triggered in some cases when `y' is empty, should only affect versions of the library obtained with the `--enable-assertions' configuration flag. o Fixed a bug in Polyhedron::check_universe(), which was returning the wrong result when called on a zero-dim universe polyhedron. o Fixed a bug in NNC_Polyhedron::NNC_Polyhedron(ConSys& cs) whereby an invariant was violated in case `cs' was empty. This bug should only affect versions of the library obtained with the `--enable-assertions' configuration flag. -------------------------------------------------------------------------- NEWS for version 0.4 (released on July 1, 2002) -------------------------------------------------------------------------- New and Changed Features ======================== o Added full support for Not Necessarily Closed (NNC) polyhedra: - creation of strict inequality constraints and mixed constraint systems; - creation of closure points and extended generator systems; - added classes C_Polyhedron (for the representation of Closed polyhedra) and NNC_Polyhedron (the user no longer can create Polyhedron objects); - added topology compatibility checks to avoid mixing objects of the two kinds; - added explicit constructors to create a polyhedron of a given topology kind starting from a polyhedron of the other kind; - added methods Polyhedron::is_topologically_closed() and Polyhedron::topological_closure_assign(); - implemented methods Polyhedron::minimized_constraints() and Polyhedron::minimized_generators() to obtain minimal descriptions, both for closed and for NNC polyhedra. o New method Polyhedron::time_elapse_assign(const Polyhedron&): it computes the time-elapse operation defined in N. Halbwachs, Y.-E. Proy, and P. Roumanoff. Verification of real-time systems using linear relation analysis. Formal Methods in System Design, 11(2):157-185, 1997. o New method Polyhedron::is_bounded(): it returns true if and only if the polyhedron is bounded, i.e., finite. o New methods Polyhedron::bounds_from_above(const LinExpression& e) and Polyhedron::bounds_from_below(const LinExpression& e): they return true if and only if the linear expression `e' is bounded from above/below in the polyhedron. o New, complete C interface. As a demo, a toy solver for pure linear programming problems has been implemented using this interface. Notice that solving linear programming problems is completely outside the scope of the library. As a consequence the toy provided as a demo is only a toy provided as a demo. o Revised and completed Prolog interface: - now supporting GNU Prolog, SICStus Prolog, SWI Prolog and YAP. - all predicates have been renamed to match their intended semantics; - arguments have been reordered where necessary so as to follow the rule "input arguments before output arguments"; - predicates added so that all the public methods for Polyhedra in the C++ library are available as Prolog predicates; - the interface has been extended to allow for closed and not necessarily closed polyhedra. o Added support for timeout-guarded operations. It is now possible for client applications to safely interrupt any exponential computation paths in the library and get control back in a time that is a linear function of the space dimension of the object (polyhedron, system of constraints or generators) of highest dimension on which the library is operating upon. o The methods named convex_hull_* and convex_difference_* have been renamed poly_hull_* and poly_difference_*. o All methods named *_and_minimize() now return a boolean flag that is false if the result is empty. o All method and variable names containing the word "vertex" have been replaced by names containing the word "point" (some previous uses of the word "vertex" were not formally correct). o The methods Polyhedron::includes(const Generator&) and Polyhedron::satisfies(const Constraint&) have been removed, as well as the enumeration GenSys_Con_Rel. They have been replaced by the new methods Polyhedron::relation_with(const Generator&) and Polyhedron::relation_with(const Constraint&), which return values of the new enumeration types Relation_Poly_Gen and Relation_Poly_Con, respectively. o The method Constraint::coefficient(void) has been renamed to Constraint::inhomogeneous_term(void). o The methods Polyhedron::widening_assign() and Polyhedron::limited_widening_assign() have been renamed Polyhedron::H79_widening_assign() and Polyhedron::limited_H79_widening_assign(), respectively. This emphasizes the fact that they implement extensions of the widenings introduced in N. Halbwachs. D�termination Automatique de Relations Lin�aires V�rifi�es par les Variables d'un Programme. Th�se de 3�me cicle d'informatique, Universit� scientifique et m�dicale de Grenoble, Grenoble, France, March 1979. and described in N. Halbwachs, Y.-E. Proy, and P. Roumanoff. Verification of real-time systems using linear relation analysis. Formal Methods in System Design, 11(2):157-185, 1997. o The library no longer calls abort(): appropriate exceptions are always thrown instead. Bugfixes ======== o Fixed a bug whereby creating a point with a negative denominator caused the library to misbehave. o Fixed a bug in Polyhedron::add_constraints(ConSys&) whereby we could have created constraint systems having rows with different capacities. o Several other bugs have been fixed. -------------------------------------------------------------------------- NEWS for version 0.3 (released on February 26, 2002) -------------------------------------------------------------------------- New Features ============ o The library has been ported under libtool: it is now possible to build dynamic libraries as well. o We now use the integer C++ class of GMP to represent the coefficients of constraints and generators, instead of our own (very much inferior) Integer class. The drawback is that we now require GMP 4.0.1 or higher. o New methods Polyhedron::convex_difference_assign(const Polyhedron&) and Polyhedron::convex_difference_assign_and_minimize(const Polyhedron&). They assign to `*this' the convex hull of the set-theoretic difference of `*this' and the argument (possibly non minimized or minimized, respectively). o The method Polyhedron::add_generators(GenSys&) is now lazy, i.e., no minimization is performed. Adding generators and minimizing at the same time is provided by the method Polyhedron::add_generators_and_minimize(GenSys&). These methods now throw an exception if the resulting polyhedron would be illegal. o Some performance improvements. o Added more test programs. Bugfixes ======== o Fixed Polyhedron::satisfies(const Constraint&) and Polyhedron::affine_image(). o Polyhedron::limited_widening_assign(const Polyhedron&, ConSys&) was erroneously returning a (random) boolean: it is now a void method. -------------------------------------------------------------------------- NEWS for version 0.2 (released on November 14, 2001) -------------------------------------------------------------------------- New Features ============ o Massive API changes. This would not normally be called "a feature", but the old API was very wrong in a number of ways. More API changes are to be expected for the next few releases. o All user-accessible library methods are now guarded by suitable sanity checks. Exception are thrown whenever the library is not called in the intended way. o A SICStus Prolog interface is now available. It comes with a somewhat interesting demo: a toy CLP(Q) interpreter. o Greatly improved documentation. Bugfixes ======== o Many, many more than we would like to admit. -------------------------------------------------------------------------- NEWS for version 0.1 (released on October 24, 2001) -------------------------------------------------------------------------- New Features ============ o The library has been released under the GNU General Public License.