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i am performing parameter identification for a non-linear partial differential equation (elasticity) that I solve with finite elements.

My optimization problem is a non-linear least squares data-fitting problem because I want to fit the parameters to measured data, e.g. coming from Digital-Image-Correlation. The residual vector within the optimization is the solution vector (or a subset of it) of the discretized PDE.

At the moment, I use open-source software (MATLAB) to solve the optimization problem, but I feel I have to get more background about optimization in the context of finite element model updating. I rely on interior-point and trust-region methods to solve the optim problem.

For finite elements, I know typical reference books that are common in this field, but for optimization, I do not know many yet. I found books like "Numerical Optimization from Nocedal and Wright", but I do not have the expertice to assess whether this is a common book in numerical optimization or not.

I thought it is useful to reach out to the community with this question since it maybe also helps other people in the future.

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    $\begingroup$ Nocedal and Wright is a very common and thorough book on the topic. If you already have adjoints/gradients available, then you can use pretty much any gradient-based optimization algorithm. You just need to be sure that your adjoints/gradients are accurate and that your linear solvers are appropriate. $\endgroup$
    – whpowell96
    Nov 25, 2023 at 18:03
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    $\begingroup$ Perhaps the right thing to search for is "pde constrained optimization". $\endgroup$
    – NNN
    Nov 26, 2023 at 2:49
  • $\begingroup$ MATLAB is pretty much the opposite of "open source software" :-) $\endgroup$ Nov 27, 2023 at 17:36
  • $\begingroup$ @WolfgangBangerth That is 100% correct, do not know why me head connected open source with matlab :-) $\endgroup$
    – Simon
    Nov 28, 2023 at 16:12

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I've worked on something quite similar for my Ph.D.. And I did not need anything more than a basic understanding of optimization. We used L-BFGS for that article, which works pretty well. Of course, better optimization alogrithms will yield better results, but to get something working, L-BFGS is a good start. The wikipedia page or Numerical Methods in C/C++/Fortran is enough to get you started.

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