[MITgcm-support] Particle tracking with MITgcm (flt package)

[Jean-Michel Campin]

Hi Andrea,

Just one clarification:
>I have used it with cartesian and sphericalpolar grids. I to NOT know if
>it works correctly with llc / exch2 / etc. Maybe Jean Michel can
>enlighten us.

I believe pkg/flt is working correctly with pkg/exch2. There are indeed some
pkg/exch2 routines (within pkg/flt) to deal with this configuration:
 flt_exch2.F , exch2_recv_get_vec.F , exch2_send_put_vec.F

Cheers,
Jean-Michel

On Fri, Oct 14, 2016 at 03:54:31PM +0200, Andrea Cimatoribus wrote:
> Thanks a lot for the reply! I will also certainly start looking at
> the python repo as soon as I start getting my hands dirty with the
> flt package.
> Cheers,
> Andrea
> 
> Andrea Cimatoribus
> postdoctoral researcher
> EPFL ENAC IIE ECOL
> https://people.epfl.ch/andrea.cimatoribus
> 
> On 14/10/16 15:44, Ryan Abernathey wrote:
> >Andrea, you are right that the MITgcm flt package is not well
> >documented. However, it IS very capable and is almost certainly more
> >efficient / scalable than offline codes, since it parallelizes along
> >with the rest of MITgcm.
> >
> >
> >    THE QUESTIONS to the MITgcm masters:
> >    - does anyone know if flt can actually deal with curvilinear grids
> >    and 3D advection (if I understand right, the answer to the latter is
> >    yes)?
> >
> >
> >I have used it with cartesian and sphericalpolar grids. I to NOT know if
> >it works correctly with llc / exch2 / etc. Maybe Jean Michel can
> >enlighten us.
> >
> >It has options for the floats to be truly 3D, isobaric, or profiling. So
> >yes, 3D advection works.
> >
> >
> >    - Is there any other verification available? I cannot find any
> >    data.flt other than the one under flt_example.
> >
> >
> >Not that I know of. Here is another example:
> >
> > &FLT_NML
> ># 1 day
> > flt_int_traj = 86400.,
> > flt_int_prof =  0.0,
> > flt_noise    = 0.0,
> > flt_selectTrajOutp = 3,
> > flt_file     = 'flt_ini_pos_hex.epac.32deg.bin',
> > &
> >
> >It is pretty simple. A lot of the float behavior is determined in the
> >input file, rather than data.flt.
> >
> >
> >    - What about advection schemes? README.flt states that second-order
> >    Runge-Kutta is the only option, but I was wandering if that is still
> >    the case and whether that is important (I am only starting to
> >    scratch the surface of Lagrangian methods).
> >
> >
> >Runge-Kutta 4th order was implemented by Andreas Klocker, and this is
> >the default. I believe this is considered state of the art.
> >
> >
> >    - Can flt actually interface to the diagnostic and mnc packages? A
> >    grep in its directory returns nothing, but my understanding of the
> >    workings of the code is certainly limited at best.
> >
> >
> >No. The float output is quite primitive and is on a tile-by-tile basis.
> >This makes it hard to parse and aggregate the float data. To deal with
> >this, we have created a python package called floater which parses and
> >translates the float data into other more convenient storage formats:
> >https://github.com/rabernat/floater
> >There is also some basic capability for writing the float input files.
> >There is still lots of room for improvement here, but it should be
> >easier than starting from scratch. I welcome issue reports and pull
> >requests on this repository.
> >
> >
> >    Thank you very much,
> >    Andrea
> >
> >    --
> >    Andrea Cimatoribus
> >    postdoctoral researcher
> >    EPFL ENAC IIE ECOL
> >    https://people.epfl.ch/andrea.cimatoribus
> >    <https://people.epfl.ch/andrea.cimatoribus>
> >
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> >
> >
> >
> >
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