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on-restart-benchmarks/share/minizinc/linear/fzn_lex_lesseq_int.mzn
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MiniZinc

%-----------------------------------------------------------------------------%
% Requires that the array 'x' is lexicographically less than or equal to
% array 'y'. Compares them from first to last element, regardless of indices
%-----------------------------------------------------------------------------%
opt bool: UseCPLexLesseq; %% When not UseOrbisack, use CP decomposition
opt bool: OrbisackAlwaysModelConstraint; %% Use with SCIP 7.0.2
predicate fzn_lex_lesseq_int(array[int] of var int: x,
array[int] of var int: y) =
assert(length(x) == length(y), %% SCIP cannot
"lex_lesseq_int(\(x), \(y)): arrays of different lengths")
/\
if MZN__Orbisack /\
dom_array(x) subset 0..1 /\ dom_array(y) subset 0..1 then
fzn_lex_lesseq__orbisack(x, y,
( occurs(OrbisackAlwaysModelConstraint) /\
deopt(OrbisackAlwaysModelConstraint) ) \/
not mzn_in_symmetry_breaking_constraint())
elseif occurs(UseCPLexLesseq) /\ deopt(UseCPLexLesseq) then
fzn_lex_lesseq_int__CP(x, y)
else
fzn_lex_lesseq_int__MIP(x, y)
endif;
predicate fzn_lex_lesseq_int__CP(array[int] of var int: x,
array[int] of var int: y) =
let { int: lx = min(index_set(x)),
int: ux = max(index_set(x)),
int: ly = min(index_set(y)),
int: uy = max(index_set(y)),
int: size = min(ux - lx, uy - ly),
array[0..size+1] of var bool: b }
% b[i] is true if the lexicographical order holds from position i on.
in
b[0]
/\
forall(i in 0..size) (
b[i] = ( x[lx + i] <= y[ly + i]
/\
(x[lx + i] < y[ly + i] \/ b[i+1])
)
)
/\
b[size + 1] = (ux - lx <= uy - ly)
;
predicate fzn_lex_lesseq_int__MIP(array[int] of var int: x,
array[int] of var int: y) =
let { int: lx = min(index_set(x)),
int: ux = max(index_set(x)),
int: ly = min(index_set(y)),
int: uy = max(index_set(y)),
int: size = min(ux - lx, uy - ly),
array[0..size] of var 0..1: fEQ;
array[0..size] of var 0..1: fLT;
} in
sum(fLT) <= 1
/\
fEQ[0] + fLT[0] == 1
/\
forall(i in 1..size) (
fEQ[i-1] == fEQ[i] + fLT[i]
)
/\
forall(i in 0..size) (
aux_int_eq_if_1(x[lx+i], y[ly+i], fEQ[i])
/\
aux_int_lt_if_1(x[lx+i], y[ly+i], fLT[i])
)
;
%% SCIP constraint handler orbisack
predicate fzn_lex_lesseq__orbisack(
array[int] of var int: vec1, array[int] of var int: vec2, bool: isModelCons);
%-----------------------------------------------------------------------------%