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Commulative integrals

Kristian Bødker Frederiksen

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Hi,

In the old COMSOL there used to be a "quad" command for computing integrals, with specific boundaries, on a subdomain for instance. In COSMOL 3.5a that's gone, and you can now only compute entire subdomain integrals.
Is there some way to still compute these without going to MATLAB?

I found that you can get somewhat what you want by making an integral coupling variable:

int_c = c*(x<dest(x))

but the result is "chappy" and "wavy" for some reason.... Any help would be greatly appreciated.

1 Reply Last Post 30 sept. 2009, 10:59 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 2 decades ago 30 sept. 2009, 10:59 UTC−4
Hi

I find it difficult to understand what your are really attempting to do, is it possible to give us a simple example

int_u = u*(x<1) should work, but is this really what you want ?

My way around when integrating over partial sub-domains (or surfaces for 3D) is to split the 3D surface with m CD tool and then select only the part of interest.

See also te discussion startd by Noemi Petra on "exporting data from the boundary"

Good luck
Ivar
Hi I find it difficult to understand what your are really attempting to do, is it possible to give us a simple example int_u = u*(x

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