[Gmsh] file format

[Rui Maciel]

oka wrote:
> Dear Rui Maciel,
> 
> Thank you so much for quick response.
> 4 5 0 1 2 1 -4 
> about 1 2 1 -4, manual has no explanation.
> I guess
> 2 means this mesh in overlap region
> 1 means partition number
> -4 means overlap facing opposite mesh number (4)
> Is this true ?


Considering that the <element tags> field taken from the example element entry 
consists of the following set of tokens:

5 0 1 2 1 -4 


According to the MSH ASCII file format reference, those tokens should be 
interpreted as:

5 => number of tags present in this element's tag field

0 => physical entity reference

1 => geometrical entity reference

2 => mesh partition reference

1 => undocumented

-4 => undocumented and, according to the manual, invalid.


To be sure it would probably be better to dig through Gmsh's MSH export 
routine.  I've took a crack at it but unfortunately I was unable to find the 
exact code which exports that part of the document.  Still, in alterantive you 
could simply ignore those offending tags, as the remaining info is still valid 
and it's still possible to resume parsing without any major consequences.


Hope this helps,
Rui Maciel