mirror of https://github.com/xianyi/OpenBLAS.git
71f2260186
When eigenvalues are nearly degenerate, numerical accumulation in the divide-and-conquer merge can push w[i] slightly above zero. The subsequent sqrt(-w[i]) then produces NaN, which propagates through the entire eigenvector output of DSYEVD/DSTEDC. Use fmax(-w[i], 0.0) to safely clamp the sqrt argument, yielding zero instead of NaN for spuriously positive w[i]. The fmax call maps to a single vmaxsd instruction on x86_64 with zero overhead. Add test/test_laed3_nan.c which exercises DSYEVD on a rank-1 perturbed identity matrix designed to create near-degenerate eigenvalue clusters. |
||
|---|---|---|
| .. | ||
| getf2 | ||
| getrf | ||
| getrs | ||
| laed3 | ||
| laswp | ||
| lauu2 | ||
| lauum | ||
| potf2 | ||
| potrf | ||
| trti2 | ||
| trtri | ||
| trtrs | ||
| CMakeLists.txt | ||
| Makefile | ||