Release Notes

Version 5.5 (2002-11-21)

• full version of XPRESS-MP for academic use is included, allowing to tackle large-scale LP/MIP problems
• new tutorial document "ECLiPSe - An Introduction"
• new library implementing SBDS (symmetry breaking during search)
• new development support libraries for source checking and cross referencing
• performance and functionality enhancements to the interval constraint solver lib(ic)

Embedded XPRESS-MP LP/MIP solver from Dash Optimization

ECLiPSe Tutorial

LP/MIP solver interface: lib(eplex)

• The new XPRESS-MP library API is now used by the eplex interface. This change should be largely transparent to the user, except that:
• There is no longer a hard limit on the number of problems (eplex instances) that can be solved at the same time.
• XPRESS solver parameters are now local to a problem, rather than global to all problems.
• If XPRESS solver parameters are accessed directly, then be aware that they have changed completely under the new API. Refer to the XPRESS 13 manual for a full list of the parameters and how they correspond to the parameters from the old API.
• Various restrictions have been lifted on when and how constraints can be posted to an eplex instance/problem. Essentially there should no longer be any restrictions on when constraints (both integers/1 and the arithmetic constraints) can be posted:
• integers/1 constraint can be posted for any problem variables at any time (previously there were various restrictions on which variables and when the integers constraints can be posted).
• If the XPRESS MP solver is used, a problem can now be freely modified by posting extra constraints to it and re-solved. Previously, if a  problem had integers/1 constraints (i.e. a MIP problem), then it cannot be modified after it has been solved once.
• Added new predicates for eplex instances:
• eplex_read/2
• eplex_write/2
• eplex_set/2.
• Added options to the setup of a problem:
• post_equality_when_unified
• write_before_solve
• mip_use_copy
• Solver's parameters needs to be wrapped by optimizer_param(Param) when they are accessed, instead of just passing Param directly.
• Solver parameters can now be accessed via a problem as well as globally.
• lp_unify_same_handle event has been removed; added lp_set_default_warning event.
• Added shortcuts lib(ic_eplex_xpress) and lib(ic_eplex_cplex).
• Various bug fixes.
• Added support for CPLEX 8.0, XPRESS 13.26 (support withdrawn from CPLEX 4.0). Note that CPLEX 8.0 for Linux does not load with glibc 2.1.

Interval constraint solver: lib(ic)

• Revised low-level interface. Click here for details. This should only affect users who have written their own constraints or access information about the domains of variables.
• Improved efficiency, improved precision and bug fixes.
• Added reified domain assignment/check ::/3, for single variables.

Symmetry Breaking During Search library: lib(fd_sbds/ic_sbds)

• New library for dealing with symmetry in constraint programming, implemented by W. Harvey (Imperial College London) and K. Petrie (University of Huddersfield), and based on the approach presented in

I.P. Gent and B.M. Smith. Symmetry breaking in constraint programming. In W. Horn, editor, Proceedings of ECAI-2000, IOS Press, 2000, pp. 599-603.

• Works with finite integer domains, finite set domains, and in principle other domains as well.
• Available in both FD and IC versions.
• Supported as an option in the fd_search and ic_search modules.
• Supported as an option by insetdomain/4 in fd_sets and ic_sets.

Other Libraries

lib(ech)

Introduced priorities for CHR constraints. Previously, ECH/CHR could have problems when used with other solvers due to differences in the priority at which the CHR rules are executed. (lib(chr) still has this problem).

Various bug fixes.

lib(fd_sets/ic_sets)

Added ic_sets, a port of fd_sets to the IC solver.

Added reified in/3 constraint.

Set expressions have been allowed in more contexts.

lib(graph_algorithms)

New graph manipulation predicates:

• graph_get_edges/4
• graph_reverse_edges/2
• is_sub_graph/2

New shortest path predicates (see overview in reference manual):

• all_short_paths_as_edges/6
• all_short_paths_as_graph/6
• single_pair_short_path/6
• single_pair_all_short_paths_as_graph/7
• possible_path/6
• shortest_paths_bellman_ford/4
• single_pair_shortest_path_bellman_ford/5

Deprecated predicates:

• all_shortest_paths/4
• single_pair_all_shortest_paths/5
• single_pair_all_short_paths/6

Performance enhancements for shortest path functionality.

lib(hash)

New predicates:

• hash_contains/2
• hash_count/2
• hash_delete/2
• hash_erase/1
• hash_get/3
• hash_set/3

lib(test_util)

Now prints line numbers for the failed tests.

lib(lists)

splice/3 now works backwards.

lib(iso)

Added missing sub_atom/5 compatibility predicate.

New library: lib(xref)

A development tool for computing cross-reference information.

New library: lib(lint)

A development tool for finding likely programming errors and checking programming conventions.

Development Environment

• Visualisation tools
• The visualisation tools have been made more scalable and light-weight.
• Tracer/Debugger:
• Added display of execution priority on a trace line if the current priority is not the default.
• Several primitives that were previously hidden are now visible during tracing (arg/3, arithmetic).
• TkECLiPSe/Development tools:
• Auxiliary predicates generated by the compiler are now filtered by default in the predicate browser tool.
• Added starting of Visualisation client to the tools menu.
• Tested with Tcl/Tk 8.4 (so the Tcl/Tk interface should also work with 8.4).
• Emacs eclipse mode significantly enhanced:
• Shortcuts for navigation:   goto beginning/end of clause/predicate.
• Shortcuts for marking regions:   mark buffer/clause/predicate.
• New indentation facilities:    indent clause/predicate.
• Shortcuts for anonymising variables (adding "_") or replacing variables by "_", for all variables in current region.
• Shortcuts for inserting:
• Predicate template ("foo(,,)").
• Predicate specification ("foo/3").
• Clause head ("foo(,,) :-").
• Shortcuts for inserting comment/2 clause heads without or with arguments.
• Four levels of fontification.
• help/1 now also lists library summaries.

Kernel features

• substring/5
• For creating user-defined tracer ports for debugging:
• trace_call_port/3
• trace_point_port/3
• trace_exit_port/0
• trace_parent_port/1
• attached_suspensions/2, for retrieving the suspensions attached to a global trigger.

• The local declaration accepts a new specifier reference/2 which is used to declare a reference with an initial value.
• Error handlers can now be of arity 4. The extra argument is the lookup module which is needed to call the culprit goal from within the error handler in case the goal is not visible there.

• Bounded real arithmetic should now be faster and more precise.

Incompatibilities

• Floating point: support for single precision floats has been removed.
• Floating point: negative (-0.0) and positive zeros (0.0) are no longer considered identical by the "syntactical" equality operators like =/2, ==/2, \=/2, \==/2. The term comparison builtins compare/3, @=<, etc. now consider -0.0 to be before 0.0 in the term order rather than being identical. Predicates that use term order are also affected, for example sort/2 will no longer consider zeros with different signs as duplicates and eliminate them. The behaviour of arithmetic comparisons and operations has not changed: -0.0 and 0.0 are considered equal by =:=/2, </2 etc.
• Bounded reals: similar to floats, the different zeros are treated as different by the "syntactical" equality operators, but are considered identical by the arithmetic comparisons.
• Bounded reals: the "syntactical" equality operators now consider bounded reals as identical when they have identical bounds. The 'undecidable comparison of bounded reals' exception is no longer raised by default. A global flag 'breal_exceptions' has been added which can be set to enable the previous behaviour. The arithmetic comparison operators still delay when the comparison is undecidable.
• Struct-declarations:  when a struct is defined twice, the second definition no longer overrides the first; a warning is raised instead and the redefinition is ignored.
• Suspension list names in suspend/3,4: the structure declaration that defines the name must be visible in the module where suspend/3,4 is called.
• setarg/3 detects the error of modifying a read-only ground term.
• lib(eplex) for  solvers with parameters local to a problem (currently XPRESS 13), the `global' parameters now refer to the global default values.
• The obsolete library lib(structures) should no longer be used, it is only backward compatible for the basic functionality.

Previous release notes

• 5.4
• 5.3
• 5.2
• 5.1
• 5.0
• 4.2
• 4.1
• 4.0
• 3.6 and 3.7
• 3.5.2