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[Lapack] Bugs in DLASD8 and DLASD6

We got a fatal error message "On entry to DLASD4 paramater number -1 had an
illegal value" when using IpOpt. We think this is due to a bug in Lapack.

The bug is in DLASD8 (see line 276 to line 284 of DLASD8
which calls DLASD4 and then handles the INFO =1 error return incorrectly.
The error indicates that DLASD4 failed to converge and should have been
reported as an INFO = 1 return to DLASD8's caller. It should not have been
passed to XERBLA. We also see similar bugs in DLASD6 (see line 414 to line
422 of DLASD6

DLASDA shows what we think is the correct behavior (see line 486 to line
507 of DLASDA
Here it is just passing the info value from DLASD6 back as the info value
from DLASDA which is reasonable (setting info = 1 before returning might be
cleaner). This method allows the higher-level subroutine that called DLASDA
to recover from low-level convergence failure. We think that's the fix we
need done in DLASD8 and DLASD6.

Thanks a lot for your attention.

Justin (Weiguang Si)

Postdoctoral Researcher
Neuromuscular Biomechanics Lab
Stanford University

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