Fix MBM Implementation. #132
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #132 +/- ##
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- Coverage 99.35% 99.35% -0.01%
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Lines 1858 1855 -3
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… and per-bound M value usage
dnguyen227
commented
Jan 9, 2026
| M::Dict{LogicalVariableRef{M}, T} | ||
| default_M::T | ||
| conlvref::Vector{LogicalVariableRef{M}} | ||
| M::Dict{LogicalVariableRef{M}, Union{T, Vector{T}}} |
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Now storing M values for vector constraints as vectors to reflect unique values in each of rows.
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This PR fixes the MBM implementation to use the tightest M values possible. This means that each disjunct constraint has it's own M value associated with any other disjunct. Originally only disjuncts has corresponding M values.
EXAMPLE
Given a disjunction with:
x <= 2andx >= 10 <= x <= 55When reformulating Y[1]'s constraints with respect to Y[2]'s feasible region (0 ≤ x ≤ 55):
x <= 2: max(x - 2) → M = 53 (at x = 55)x >= 1: max(1 - x) → M = 1 (at x = 0)Before (max M of possible constraints):
x - 53·Y[2] <= 2
x + 53·Y[2] >= 1 ← Both use M = max(53, 1) = 53
After (per-constraint):
x - 53·Y[2] <= 2 ← Uses its own M = 53
x + 1·Y[2] >= 1 ← Uses its own M = 1 (tighter)
The code is largely the same. The change made is
maximum(_maximize_M(...))is now just_maximize_M(...), and order of for loops was adjusted to reflect this.Relevant tests were added to check for these unique M values in addition to verbose comments.