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

[akobotov]

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

[admin]

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

[admin]

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