FA-15457 / Numerics / Member archive
Exact ldl decomposition: off diagonal schur complement · case 02
The exact exact ldl decomposition result violates the stated contract at off diagonal schur complement.
Case contract
Input symmetric positive definite integer matrix; return unit lower L and diagonal D as rational pairs such that A=L*D*Ltranspose.
Why this case matters
Exact discrete arithmetic with observable algorithmic state; no floating point approximation is used.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| explicit oracle 0 | [[[[1, 1], [0, 1], [0, 1]], [[2, 11], [1, 1], [0, 1]], [[6, 11], [13, 25], [1, 1]]], [[11, 1], [150, 11], [51, 25]]] | [[[[1, 1], [0, 1], [0, 1]], [[2, 11], [1, 1], [0, 1]], [[6, 11], [9, 25], [1, 1]]], [[11, 1], [150, 11], [99, 25]]] | Failed |
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