[Gmsh] saving the mesh for a subdomain separately

[G. D. McBain]

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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
Le mardi, novembre 20, 2018 4:58 AM, Abiti Adili <aadili1 at lsu.edu> a écrit :

> I have created an unstructured tetrahedral mesh on a unit cube with a sphere in it by using graphical user interface.
> I was able to save the mesh for the whole cube as a msh file and read it into Matlab using load_gmsh2 function.
>
> I need the portions of the mesh for the sphere as well as the one for outside the sphere separately read into Matlab for my problem.
>
> I have read in one posting that you can "turn off" the mesh information for a desired subdomain but having troubles figuring out how.
>
> I would greatly appreciate if someone could explain or give directions on what needs to be done for saving the msh file only for a desired subdomain.

One approach is to split the input files.  Put everything quoted into one file, say "geometry.geo", then Include [0] that in each of two others in which the desired subsets of physical entities [1] are defined.

[0] http://gmsh.info/doc/texinfo/gmsh.html#index-Include-char_002dexpression_003b

[1] http://gmsh.info/doc/texinfo/gmsh.html#Elementary-entities-vs-physical-groups