[petsc-users] Bug Report TaoALMM class

[Matthew Knepley]

Toby and Hansol,

Has anyone looked at this?

  Thanks,

     Matt

On Mon, Jun 12, 2023 at 8:24 AM Stephan Köhler <
stephan.koehler at math.tu-freiberg.de> wrote:

> Dear PETSc/Tao team,
>
> I think there might be a bug in the Tao ALMM class:  In the function
> TaoALMMComputeAugLagAndGradient_Private(), see, eg.
>
> https://petsc.org/release/src/tao/constrained/impls/almm/almm.c.html#TAOALMM
> line 648 the gradient seems to be wrong.
>
> The given function and gradient computation is
> Lc = F + Ye^TCe + Yi^T(Ci - S) + 0.5*mu*[Ce^TCe + (Ci - S)^T(Ci - S)],
> dLc/dX = dF/dX + Ye^TAe + Yi^TAi + 0.5*mu*[Ce^TAe + (Ci - S)^TAi],
>
> but I think the gradient should be (without 0.5)
>
> dLc/dX = dF/dX + Ye^TAe + Yi^TAi + mu*[Ce^TAe + (Ci - S)^TAi].
>
> Kind regards,
> Stephan Köhler
>
> --
> Stephan Köhler
> TU Bergakademie Freiberg
> Institut für numerische Mathematik und Optimierung
>
> Akademiestraße 6
> 09599 Freiberg
> Gebäudeteil Mittelbau, Zimmer 2.07
>
> Telefon: +49 (0)3731 39-3173 (Büro)
>
>

-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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