XCSP3 2026 tracker PR

[tias]

Runner infrastructure: (lead: Thomas)

• merge in the tools-paper-based runner/dataset/io branch
• make tools/xsp3 runner call the new runner and delete all other (unnecessary) files in tools/xcsp3 (or do deprecation warnings/callers on key entry points)
• fix failing tests of this PR

Globals in XCSP3 that are not in master (often positive-only) (lead Wout)

• MDD global constraint #924 goes to master
• in xcsp3 parser, use the above MDD constraint
• Linear decomposition for Table using MDD #945
• Reduce MDD #949
• Positive decomposition #980 (through master)
• Linear decomposition for Regular using MDD #981 (did not seem beneficial based on run, instead reuse decomposition based on transition table and add positive decomposition)

Other improvements (efficiency) (lead Ignace)

• varmap str Varname in varmap instead of variable object #990
• solver_vars update simpler solver_vars improvement #992
• decomposed typed pattern refactoring decompose in typed pattern #929
• solver_var update for all solvers Fast path solver var #995
• Read integers with round i/o int for Gurobi #884
• floatsum floatsum to still enable floats in the objective #957
• simplify_bool (blocked by floatsum) simplify_boolean in the new pattern (9s -> 6s flatten) #959

Encoding improvements (see aspriational xfails en #912) (lead: Orestis)

• Use order encoding for inequalities use order encoding for inequalities #994
• Canonalize inequalities to all take form x >= k canonicalize inequalities #996
• Only post channeling constraints, when integer value used in model Selective channeling for Exact #1000

Final sprint

• Cumulative auto heuristic from XCSP3 global: put in master (Thomas)
• check all globals in xcsp3 parser and whether they can be cut and/or replaced by positive decompose (Wout) Positive globals #1006
• Runner instructions (Thomas)
• Install instructions (Thomas)
• Run on test instances (new set for 2026) (Thomas)

Optionally afterwards if somebody is motivated:

• ShortTable decomposition #997

Benchmarking queue:

• MDD reduce
• simpl_bool
• Positive decompositions
• Exact SoPlex
• GCC decomp
• Positive globals [cancelled]
• Revert to competition Regular [running]
• Fixes to parser

Candidate solvers to submit: ortools, cpo, gurobi, highs, scip, exact, pindakaas(SAT), pumpkin?
Tracks: COP, CSP, //