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Dark side of Amdahl's law. Part II

Posted December 4, 2011 at 10:57 by SergeAS
Updated December 4, 2011 at 11:44 by SergeAS
Tags mpi, parallel

Let us consider in more detail how works domain decomposition in the simplest 1D case.
The computational domain is divided into several subdomains along one (usually the longest) dimension. The number of such subdomains usually corresponds to the number cores involved. The main data exchanges take place between neighboring subdomains. The size of transmitted data between adjacent subdomains in the general case depends on many factors (number of equations in the system, the size of the computational...
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Dark side of Amdahl's law

Posted November 25, 2011 at 16:19 by SergeAS
Updated November 27, 2011 at 06:44 by SergeAS
Tags mpi, parallel

Looking the latest HPCSource I came across very well-known picture, illustrating the Amdahl's law:
S_p = \cfrac{1}{\alpha + \cfrac{1 - \alpha}{p}}


which shows the dependence of the speedup parallel code on number of processor cores for different fraction of time (\alpha \ne 0) spent in the part that was not parallelized. This diagram is interested in me for the...
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Notes about running OpenFOAM in parallel

Posted February 27, 2011 at 10:22 by wyldckat
Updated October 31, 2015 at 09:25 by wyldckat (added more links)

This is a rough list of informations to be compiled and posted on openfoamwiki.net on a page about running OpenFOAM in parallel. If someone picks up on this and wants to start the article in the wiki, be my guest. Leave a comment pointing to the wiki page, so we can cooperate

List of already catalogued applications on the wiki for pre/post processing for parallel mode: http://openfoamwiki.net/index.php/Ca...sing_utilities
Yet to be catalogued:
  • redistributeMesh
  • renumberMesh
...
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The End of Clusters?

Posted March 30, 2009 at 20:58 by gocarts

Are we approaching the end of cluster computing for CFD? Or is it simply the end of the beginning of an era to be further dominated by clusters?

The premise is that a collection of computers (a cluster) can process data in parallel much faster and more cost effectively than a single standalone computer. Until recently clusters were the only viable means to compute large CFD simulations for engineering applications, such as those found in Formula 1.

Now we have available...
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