Hi Pauline,
Some quick input, I really hope others can provide more detailed help.
A small example on how to define the jacobian in ARTS:
jacobianInit
jacobianAddAbsSpecies( jacobian_quantities, jacobian_agenda,
atmosphere_dim, p_grid, lat_grid, lon_grid,
retrieval_grid, lat_grid, lon_grid,
"O3", "analytical", "rel", 1, 0.01 )
jacobianClose
This example just considers ozone. You can make more "jacobianAdd" to
also include other quantities.
The actual calculation is done by yCalc.
If you have a control file, you run it as
arts cfile.arts
For help do
arts -h
For example, to control screen output
arts -r22 cfile.arts
Just a quick into. If you have further questions, others have to answer.
Bye,
Patrick
On 07/11/16 17:24, Pauline Martinet wrote:
Hi Patrick (cc. arts users),
Thanks for your reply.
We use the on-the-fly option and not the lookup table to compute the
absorption.
Could anyone help in explaining what is the function to compute
Jacobians from ARTS alone with atmlab ?
When I have the cfile from ARTS, what is the terminal command to
execute it without any matlab interface ?
(it is probably a silly question but I really had troubles to
understand how to use ARTS without matlab this is why I never used).
Thanks a lot for your kind help,
Best regards,
Pauline
----- Météo-France ----- Dr. Pauline Martinet Chercheur
CNRM/GMEI/LISA pauline.marti...@meteo.fr Fixe : +33 561079031
----- Mail original ----- De: "Patrick Eriksson"
<patrick.eriks...@chalmers.se> À: "domenico cimini"
<domenico.cim...@imaa.cnr.it> Cc: "Stefan Buehler"
<stefan.bueh...@uni-hamburg.de>, "pauline martinet"
<pauline.marti...@meteo.fr>, "francesco deangelis1"
<francesco.deangel...@graduate.univaq.it>, "arts users mi"
<arts_users.mi@lists.uni-hamburg.de> Envoyé: Lundi 11 Juillet 2016
17:13:10 Objet: Re: Advise concerning ARTS computation speed
Dear Nico,
A relatively quick answer as I am on vacation. Please send questions
like this to the arts users mailing list. See cc.
As I understand it, this deals with the relative speed of ARTS and
RTTOV. I personally don't have any practical experience of RTTOV.
Unfortunately, there is no single recommendation on how to use ARTS
for maximum speed. The most critical aspect is how the absorption is
calculated, on-the-fly or by lookup table. On-the-fly can be the
fastest option, particularly for ground-based measurement of the
strato- and mesosphere. I assume you should use the lookup table
option. If you allow some poorer accuracy, the polynomial order used
to interpolate the lookup table could be decreased to increase the
speed. If you use standard settings, other aspects should not be
critical. It would be lengthy discuss all possible bad settings, ask
if you are unsure about any setting.
You don't need Qpack to calculate Jacobians. This can be done by
ARTS alone. However, it should be possible to time the actual time
used by ARTS to calculate the spectrum + Jacobian, even from Qpack.
Try this
Q.YCALC_WSMS = { 'timerStart', 'yCalc', 'timerStop' };
You could need to set this
atmlab('FMODEL_VERBOSITY',1)
But all this could fail, we have experienced problems with how
matlab picks up the screen output of arts.
For more advanced qpack users, one option is to set
atmlab('DEBUG',1)
and locate the relavnt temporary folder, add the time commands to
the cfile and run the cfile from the terminal.
Regards,
Patrick
------------------------------------------------------------------------
*Från:* "domenico.cimini" <domenico.cim...@imaa.cnr.it>
*Skickat:* 8 juli 2016 10:54:18 CEST *Till:* Stefan Buehler
<stefan.bueh...@uni-hamburg.de>, patrick.eriks...@chalmers.se *Cc:*
Pauline Martinet <pauline.marti...@meteo.fr>, Francesco De Angelis
<francesco.deangel...@graduate.univaq.it> *Ämne:* Advise concerning
ARTS computation speed
Dear Stefan and Patrick,
let us intrude in your mailbox for asking your advise concerning
ARTS.
Some months ago we submitted a manuscript presenting the modification
we made to RTTOV to simulate ground-based microwave radiometer
observations: http://www.geosci-model-dev-discuss.net/gmd-2016-65/
As we compare results from RTTOV and ARTS, we also reported on the
different computing times.
Referee #2 commented that the speed of ARTS depends critically on
several settings. For details, see the comment at the bottom of C3 in
the following link:
http://editor.copernicus.org/index.php/gmd-2016-65-RC2.pdf?_mdl=msover_md&_jrl=365&_lcm=oc108lcm109w&_acm=get_comm_file&_ms=50514&c=108717&salt=1176682561237999184
Of course we want to be fair with ARTS, but we may miss the
necessary familiarity with ARTS settings; thus we would like to ask
your advise on the following issues.
1. Do you have any feeling of the computation speed of ARTS with
respect to RTTOV?
2. We used ARTS + ATMLAB for the direct simulations (through the
arts_y(Q) function) and ARTS + Qpack2 to calculate and evaluate the
computation time of the Jacobians. This probably slows down the
computation as it requires a matlab interface. Is there any
recommended settings to optimize the computation speed? Is there
another solution than using Qpack to compute the Jacobian matrix with
ARTS (without coding a rather slow "brute force" method)?
Thanks much for your attention and valuable time.
Kind regards,
Nico, Pauline and Francesco
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