open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi,

I noticed that in the documentation for the external control sections file in section 5.2.2 the user manual states for the two integers in line 2:

However, in fact the steering integer may be one of the three value -1, 0, and 1, see sources/telemac2d/read_sections_telemac2d.f cases of variable IHOWSEC. The meaning of IHOWSEC = 1 is not described in the manual.

Cheers,
Tobias

Hello Tobias,

I am not a specialist of this feature. I have read some source codes, in particular what is done when dealing with parallel runs (special partitioning of control section files) when PARTEL program is run, it calls the HANDLE_SECTIONS subroutine (from the MOD_HANDLE_SECTIONS module). Then, it writes 1 at IHOWSEC location and gives segments + other stuff as case 1 in READ_SECTIONS_TELEMAC2D.

So I think the documentation is nearly all right:
- if negative number is given (< 0), it works with global number in serial and parallel runs: OK,
- if 0 is given, it works with coordinates in serial and parallel runs,
- if a positive number is given (> 0), it works with coordinates also but only for parallel runs: OK in that case.

After the call to PARTEL for a parallel run, IHOWSEC is always equal to 1 and TELEMAC-2D manages segments + other stuffs (conversion of segments from coordinates or global numbers).

I think it is not OK if you give a positive number (> 0) and run a serial computation. I do not have any example to try for this feature with this configuration at the moment, but my current understanding of what is implemented would lead to say that.

Anyway, in READ_SECTIONS_TELEMAC2D, I think there is no need to describe the IHOWSEC = 1 or more in the TELEMAC-2D user manual, but maybe give warning to use specific values when running a serial computation.

Hope this clarify your post,

Chi-Tuan

Hi Chi-Tuan,

thanks for clarification. I can confirm the issue with the serial vs. parallel runs. I was running in serial mode and was wondering about the error I got.

Of course you're right, there is no need to describe the code details (IHOWSEC = 1 etc.) in greater detail. Only the that a value of 0 is needed to give coordinates for serial runs would be great.

By the way, another issue I posted here might also be related to missing information with respect to control sections in the documentation. I posted that in another section of the forum as I thought this would be a design issue but now I think it is rather a matter of documentation or me misunderstanding some things (not sure).

Regards,
Tobias