some problems about step37

imr—hwy

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Jan 27, 2023, 5:07:21 AM1/27/23

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hello everyone！
I am learning about the step37 and want to use matrix free methods in my program. Now I am confused about the two functions` use. compute_diagonal and local_compute_diagnol. I am confused why we need to compute the elements on diagnol. thanks for your reply！

Peter Munch

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Jan 27, 2023, 5:17:53 AM1/27/23

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In this tutorial, multigrid is using Chebysev sweeps around a point Jacobi solver as smoother. Latter needs the (inverse) of the diagonal.

Hope this helps.
Peter

imr—hwy

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Jan 30, 2023, 9:37:41 AM1/30/23

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Thanks for your reply. I am still confused about a function——“phi. submit_dof_value( diagonal[i],i)”.Can I understand like that I make the i–th point's value equal to diagonal[i].For example, if diagonal[i]=1，the solution vector[i] =1. Thanks a lot！！！

发件人：Peter Munch <peterr...@gmail.com>
日期：2023年1月27日 18:17
主题：[deal.II] Re: some problems about step37
收件人："deal.II User Group" <dea...@googlegroups.com>

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