N-ary constraints

Rules over several cells checked by enumeration (lines, sums, relations). Generated from the comments in the headers by Doxygen and tools/gen_cpp_reference.py; public members only.

nary.hpp

csrc/nary.hpp

Generic multi-cell ("n-ary") constraints and their consistency engine.

A constraint is a scope of unique cells ("vars") plus a type-specific predicate over positions (positions index vars, so a cell may appear more than once, e.g. a line crossing itself). The engine enumerates assignments consistent with the current domains respecting pairwise distinctness (shared AllDiff groups / neq links / the constraint's own distinct flag) and pair-relation tables between scope cells with bound pruning, and returns per-var supports (generalized arc consistency), the number of consistent assignments, the intersection of their digit sets ("must contain") and whether that digit set is unique.

struct NSpec

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input form (from Python dicts)

Fields

• type int
• a std::vector< int > — sum/set/table cells; arrow circle
• segs std::vector< std::vector< int > > — arrow: {line}; equal_sum: segments
• total int
• distinct int — -1 auto
• setkind int — set: 0 = consecutive
• rows std::vector< std::vector< int > > — table
• quota std::vector< int > — count: index = digit, -1 = unconstrained
• line_kind int — >= 0: a line rule (LineKind)
• def_lines std::vector< int >
• def_regs std::vector< int > — derived leftovers: the defining lines / regions
• totals std::vector< int > — sum with an unknown total from this set (incomplete clue); empty = total
• named bool — table with a rule name (moves coded 6000 + index)
• offset int — equal_sum: segment sums of (digit - offset)
• bounds_only bool — sum: derived (BandLogic) brute force propagates bounds only
• seg_sign std::vector< int > — bounds_only: +1 / -1 per segment (outie cells subtracted); empty = all +1

struct NConstraint

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Name	What it does
nv	number of distinct cells (variables) of the constraint

Fields

• type int
• index int — position in Puzzle::nary_specs (-1: derived from a cage group)
• group int — cage group it was derived from
• house int — derived innie/outie region: first house of the union
• innie int — derived innie/outie region: index into Puzzle::big_innies
• set_theory bool — derived by build_set_theory (arrows / little killers in the region)
• outie bool
• n_cages int
• vars std::vector< int > — unique cells
• pvar std::vector< int > — position -> var index
• total int
• totals std::vector< int > — incomplete clue: the total is one of these (empty: total)
• distinct bool
• arith bool
• ncircle int — arrow: positions [0, ncircle) are circle digits
• seg_start std::vector< int > — equal_sum: segment k = [seg_start[k], seg_start[k+1])
• setkind int
• arity int
• named bool — table with a rule name
• offset int — equal_sum: segment sums of (digit - offset)
• bounds_only bool — derived sum: bounds propagation in brute force
• part std::vector< int > — bounds_only: var -> part id (cells of a part are pairwise distinct)
• parts std::vector< std::vector< int > > — bounds_only: cells per part
• part_sign std::vector< int > — bounds_only: +1 / -1 per part (empty = all +1)
• rows std::vector< uint8_t > — table rows over positions
• quota std::vector< int > — count
• line_kind int — >= 0: line rule (cells in line order = vars)
• differ std::vector< uint8_t > — nv*nv
• rel std::vector< const uint32_t * > — nv*nv: rel_ex(var i -> var j) or null
• order std::vector< int > — DFS order (vars)
• shape double

int nv() const

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number of distinct cells (variables) of the constraint

struct GacReq

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Fields

• v int
• varmask uint64_t — some var in mask must take v

struct GacOut

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Fields

• sup uint32_t[64]
• count pm_long — consistent assignments (capped when !complete)
• complete bool — enumeration finished within budget
• set_unique bool — all assignments use the same digit set
• must uint32_t — digits in every assignment (valid if complete)
• any bool