Relationship between the solution convergence and boundary conditions

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Discussion Overview

The discussion revolves around the convergence of solutions in the context of solving nonlinear partial equations related to atomic structure. Participants explore the potential impact of boundary conditions on convergence and seek clarification on the specifics of the problem presented.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant describes an algorithm for solving the equation [K]{u}={F} but reports convergence issues and questions the influence of boundary conditions on this convergence.
  • Another participant requests more detailed information regarding the equations, software, algorithm, and specific boundary conditions involved, emphasizing that clarity is essential for effective assistance.
  • A third participant notes that convergence problems are common and suggests that the quality of help depends on the quality of the problem description, reiterating the need for specifics.
  • There is a mention of the finite element method and a query about which factors, such as node coordinates or boundary conditions, might cause divergence in results.
  • Participants express skepticism about the necessity of developing a new algorithm given the existence of many existing solvers.
  • One participant questions the utility of asking for "tricks" to avoid convergence issues, suggesting that the problems are fundamentally mathematical rather than magical.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are multiple competing views regarding the causes of convergence issues and the necessity of developing a new algorithm. The discussion remains unresolved with ongoing requests for clarification.

Contextual Notes

The discussion lacks specific details about the equations, software, and algorithms being used, which may limit the ability to diagnose the convergence issues accurately. There are also unresolved questions about the exact nature of the boundary conditions and their potential effects.

reguieg yssaad
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Homework Statement
I want to solve the non lineaire equation using iterative calculation
Relevant Equations
[K]{u}={F}
I create an algorithm that can solve [K]{u}={F} for atomic structure, but the results are not converge
  • Do the boundary conditions affect the convergence of the resolution of a system of nonlinear partial equations?
  • And how to know if the solution is diverged because of the boundary conditions?
Thank you
 
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I looked at your post and can't make sense of what you write. Could you be a bit more elaborate ? Our telepathic capabilities are rather limited. Perhaps not everybody can immediately understand what you mean with K, u and F.

You experience convergence problems, which is not uncommon (been there, done that thousands of times). The quality of help you get depends on the quality of your description. What equations ? What software ? What algorithm ? What boundary conditions ? What crashes specifically ?

reguieg yssaad said:
I create an algorithm that can solve
Why ? Aren't there zillions of solvers around aleady ?
 
BvU said:
I looked at your post and can't make sense of what you write. Could you be a bit more elaborate ? Our telepathic capabilities are rather limited. Perhaps not everybody can immediately understand what you mean with K, u and F.

You experience convergence problems, which is not uncommon (been there, done that thousands of times). The quality of help you get depends on the quality of your description. What equations ? What software ? What algorithm ? What boundary conditions ? What crashes specifically ?

Why ? Aren't there zillions of solvers around aleady ?

This problem is found in finite element method.
In other words, Which of the following causes divergence of results :
- node coordinates
- boundary conditions
What are the tricks used to avoid these problems?
 
Does that answer any of my questions ?
  1. What equations ?
  2. What software ?
  3. What algorithm ?
  4. What boundary conditions ?
  5. What crashes specifically ?
  6. Why develop your own algorithm ? Aren't there zillions of solvers around aleady ?
Asking for tricks is rather futile at this point. It isn't magic, it's math ...

--
 

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