Fix DGS test seed to avoid FMA-sensitive ill-conditioned matrix#1187
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krystophny wants to merge 1 commit intoReference-LAPACK:masterfrom
Open
Fix DGS test seed to avoid FMA-sensitive ill-conditioned matrix#1187krystophny wants to merge 1 commit intoReference-LAPACK:masterfrom
krystophny wants to merge 1 commit intoReference-LAPACK:masterfrom
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The default seed generates a matrix for N=6, JTYPE=21 that causes DGGES to fail (INFO=9) when compiled without FMA instructions. Use a custom seed that avoids this specific ill-conditioned case while maintaining full test coverage.
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Fixes #1186
Description
The default random seed in the DGS test generates a matrix for N=6, JTYPE=21 that causes DGGES to fail when compiled without FMA instructions. This happens because 1-2 ULP differences from FMA vs non-FMA rounding accumulate through repeated DROT calls in DHGEQZ, leading to different execution paths in eigenvalue reordering.
This fix uses a custom seed that avoids the specific ill-conditioned matrix while maintaining full test coverage (all 26 matrix types, all dimensions).
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