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lexicographical version

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
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Lev Nachmanson 2026-05-15 19:20:02 -07:00
parent 2ba7d7ed70
commit ff49d60e64
2 changed files with 135 additions and 18 deletions
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11
src/math/lp/int_cube_lll.h
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@ -21,12 +21,13 @@ Abstract:
col_j(B) <- col_j(B) - q * col_k(B) (q in Z, j != k)
The optimal q for a fixed pair (j, k) is the floor or ceil of the
The q candidates for a fixed pair (j, k) include the floor/ceil of the
weighted median of the breakpoints {A_row(r,j)/A_row(r,k)} and
{B(i,j)/B(i,k)} (weights are the absolute values of the denominators);
a standard piecewise-linear minimization. We accept only strict
improvements of C(B), starting from B = I; therefore the heuristic
is never worse than the plain int_cube.
{B(i,j)/B(i,k)} (weights are the absolute values of the denominators).
They are scored lexicographically: first minimize the number/severity
of bounded rows/columns whose later delta-tightening would collapse
their box, then minimize C(B). This keeps the greedy from accepting a
cost-improving basis move that merely sets up a bail-tighten failure.
This addresses the regression of int_cube_hnf, whose triangulation
can blow up the column-delta term ||B||_1: in 153 random instances