# Questions tagged [domain-decomposition]

A parallel algorithm design approach in which the data is divided into pieces and then computations are associated with the data. This contrasts to 'functional decomposition', in which tasks or computations are divided first, then data is associated to them.

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### How to choose MPI topology for uniform 3D Cartesian grid that is not cubical?

When writing an MPI-parallelised code, I need to split a global Cartesian domain of $(N_x, N_y, N_z)$ cells among $M$ MPI ranks. For simplicity, we can assume that the decomposition is "simple&...
1 vote
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### Deconvolution of sinc function in spectrum calculation in FTS

In Fourier transform spectroscopy (FTS) I am calculating a broadband interferogram (e.m. frequency 190-300 GHz top-hat), then back-retrieving the spectrum by FT. Here in the figure, you can see the ...
92 views

### "Optimal" domain partitioning in domain decomposition algorithms

When solving a PDE numerically by domain decomposition methods, what is the "optimal way" to split the domain? Are there any results stating that a particular partition of the domain yields &...
1 vote
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### What is the difference between Adittive Schwarz as a preprocessor and a solver?

As we all know, the Additive Schwarz approach can be used as either solver or preconditioner, however, my question is, what is the difference between the two? In other words, how to use AS as solver, ...
174 views

### Partition mesh into predetermined submeshes

I have a mesh already partitioned into disjoint groups of cells. What I want to achieve is the following. Obtain the adjacency graph for the cell groups. Partition the mesh, i.e. generate submeshes ...
1 vote
92 views

### preconditioner for $u''(x)=\sin(x)$

I am interested in finding preconditioner to solve the problem for one dimensional problem $u''(x)=\sin(x), u(0)=u(1)=0$ using Dirichlet-Neumann method. The preconditioner $M$ coming from Dirichlet-...
1 vote
32 views

### can you give me some information of tools for load reblance

I want a tool for load rebalances. I have a distributed grid. Each process can handle a part of the global grid. Each process has a different node and I want to rebalance it. I want a tool that can ...
1 vote
133 views

### Parallelisation strategies for mixed FE formulations

Mixed FE formulations with LBB-stable elements require two different meshes for the primary and the constraint variables, for example, displacement and pressure. With continuous approximation for the ...
1 vote
430 views

1 vote
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### Metis: how to use and tutorial recommendation

I am new to METIS and trying to use it in my fortran code. I read the manual online. But still, I am not sure about how to implement it my code. I tried the test cases in the graphs directory. For ...
1 vote
111 views

### Partitioning SPD matrix with METIS to preserve block SPD-ness

I am using the METIS to partition a matrix and then using domain decomposition to solve the subdomains in parallel using the Restricted Additive Schwarz method. I am currently trying to solve some ...
1 vote
267 views

### Efficient evaluation of $BQ^{-1}B^T$ (Domain Decomposition Implementation)

I have implemented a schur complement domain decomposition method for solving large scale problems in Matlab. It works well but I think there should be some alternative approaches to implement some ...
1 vote
94 views

I am solving 1D laplace problem discretized with finite differences (3-point stencil). I would like to use additive Schwarz method in classical form: $U_{k+1}=U_{k}+M^{−1} r_k,$ where $r_k=F−A U_k$...
274 views

### How to precondition FEM problems using domain decomposition?

Let's say that I have a FEM code which yields the following problem: $$\mathbf{A}\mathbf{x} = \mathbf{b}.$$ In order to solve this more efficiently with an iterative method, I would like to ...
157 views

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### Mesh domain decompositions / mesh partitioning

I have some experience with mpmetis from METIS. It is pretty good software which offers unstructured mesh grid partitioning. But obtained results always minimize edgecuts or total communication volume....
166 views

### Compability conditions in domain decomposition methods

Suppose we want to solve the Poisson equation $\Delta u = f$ on a domain $\Omega$ with Dirichlet boundary conditions. One possible way to do is by a domain decomposition method. There is a condition ...