?(SY/HE)SV in LAPACK 3.3 could crash if LWORK<N

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?(SY/HE)SV in LAPACK 3.3 could crash if LWORK<N

Postby akobotov » Tue Feb 08, 2011 5:25 am

Hello,

In LAPACK 3.3 ?(SY/HE)SV are updated to use TRS2. The TRS2 requires WORK(N) to operate, whereas in SV requirements for LWORK just to be >=1. There is no any check in SV if LWORK>=N, the array WORK just passed as it is to TRS2. So if LWORK<N a crash could occur while executing TRS2 due to overuse of allocated workspace.

I guess for the case of LWORK<N just previsous Level2 based ?(SY/HE)TRS should be used.

W.B.R.,
Alexander
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Re: ?(SY/HE)SV in LAPACK 3.3 could crash if LWORK<N

Postby admin » Tue Feb 08, 2011 9:37 am

Hi Alexander,
Indeed. I will proceed with your suggested change and update the comments to warn user that they will be using a BLAS2 algo for the solve if lwork < N.
Julie
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Re: ?(SY/HE)SV in LAPACK 3.3 could crash if LWORK<N

Postby admin » Wed Feb 09, 2011 4:04 pm

Alexander,
I just committed the fix in our SVN.
See http://netlib.org/lapack/Errata/index2.html
Julie
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