How to hot-start swan?

[wamamy]

Hi all,

When I run the SWAN, it ended abruptly after 5 days running, so I'd like to hot-start it. I used the hotfile which was generated in my previous SWAN run, as my initial file. Therefore I changed the Line 'Init' to 'INITIAL HOTSTART MULTIPLE 'swan_ini.hot''. When I restart my model, it couldn't work. I have no idea about it. Is there any other place that I need to change? If anyone knows how to hot-start it, could you please tell me? Thanks very much.

Happy Modeling.

Amy

[moritz.wandres]

Hi Amy,

It would also be helpful to see your output/log file or your .erf file that is usually created when SWAN crashes.

Have you tried the SWAN mailing list?
https://sourceforge.net/p/swanmodel/mai ... del-users/
You might have more luck finding answers there than in the ROMS forum.

[wamamy]

Hi Moritz,

Thanks for your answer and suggestions. I have solved that problem. I changed the initial file, but didn't change the restart time. Therefore, the start time is before the restart time and leads to SWAN crashes. Now it works. I'm wondering could it restart automatically? I'm not sure when the model will end, so the starting time is flexible. I need to change the time manually.

Amy

[m567tej]

Dear moritz
I solved the similar problem by compiling swnhcat.F and editing hcat.nml which was exist in COAWST/SWAN/Src.
so that I edit the nml file as follow:

&arg_nml !namelist identifier
basefile = "swanrst2.dat", !(required) base file name (w/o mpi node tag)
free = .true. !(optional) free format (default .true.)
halo = 3, !(optional) halo size (default is 3)
verbose = .true., !(optional) verbose screen ouput (default .false.)
stomp = .false. !(optional) overwrite basefile (default .false.)
/

remember that you should use similar Core/Thread for using swanhcat.exe after making that. After that I changed initial file name in swan.in to new file.

majid

[wamamy]

Hi majid,

I'm wondering what's the difference between the file of 'swan_rst.dat' and 'swan_ini.hot'? In the manual, I see the hot file could be used as initial file, but I didn't find the restart file which may also could be used as initial file when I hot start the SWAN.

Thanks.

Amy

[jcwarner]

there is information in the coawst user manual, page 19.

"5.3.7) SWAN restart files.
SWAN has the command 'HOTFILE' that is used to write out the model state of two-dimensional spectra to a file at the end of the simulation. This file can be used as a restart for a future simulation. We have recently added the option to have SWAN create restart files during the simulation. This can be useful for a coupled simulation (for example a roms + swan run). If the modeling system reaches a fault during the run, the ROMS model can be restarted with the ROMS rst or his file. Now you can also restart the SWAN model with a restart file for that same instance in time. You need to add the command "RESTART'. For example, the swan.in file would need:

RESTART 'swan_intest_rst.dat' FREE 1 HR
COMPUTE NONSTATIONARY 20000101.000000 60 SEC 20000101.120000
STOP

With this set of commands, swan is going to run from Jan 1, 2000, at hour 0 to Jan 1, 2000 to hour 12, with a 60 sec time step. The 'RESTART' command will update a file called swan_inlet_rst.dat every 1 hour during that simulation. You can make this be any time you require (1 HR or 30 MIN or 12 HR or whatever). It is recommended that the user set the restart times to be the same for WRF, ROMS, and SWAN so that a consistent set of restart files are available."

if you have any more issues on this, please make a post on the coawst forum.
thanks,
john