Hi Patrick,

Thanks for your quick answer.

Simon's answer did clarify it and I believe his solution is quite close to what 
you suggest and what is done in Qpack.

I'll try it out.



De : Simon Pfreundschuh <simon.pfreundsc...@chalmers.se>
Envoyé : vendredi 4 juin 2021 14:55:24
À : Sauvageat, Eric (IAP); arts_users...@mailman.rrz.uni-hamburg.de
Objet : Re: ARTS OEM multiple inversions

Sorry, though the response would automatically go to the list. For completeness,

here's my response from earlier.

Just to clarify and confirm:

> same sensors, same atmosphere, etc.. just different measurements vectors using
> OEM from ARTS directly ?

This is what ARTS currently does: It takes multiple observations and solves for 
a single atmospheric state. If I understand you correctly what you want to do is
same sensors but different atmospheres (although they may be the same a priori).

This kind of parallelism is not supported within ARTS so you'll have to do it
sequentially. It's straight forward when you use the Python interface: After
you have set up your calculation, you just call the OEM WSM multiple times in a 
What you need to pay attention to is to  reset the WSVs x, yf and jacobian 
before calling OEM a second time because those are both in- and outputs of the 

I not sure, however, how much you will gain from this computationally since this
depends on your retrieval setup.

Let me know if anything remains unclear.

Kind regards,


From: arts_users.mi-boun...@mailman.rrz.uni-hamburg.de 
<arts_users.mi-boun...@mailman.rrz.uni-hamburg.de> on behalf of 
eric.sauvag...@iap.unibe.ch <eric.sauvag...@iap.unibe.ch>
Sent: Friday, June 4, 2021 12:03:12 PM
To: arts_users...@mailman.rrz.uni-hamburg.de
Subject: [arts-users] ARTS OEM multiple inversions

Dear ARTS community,

I am performing strato-mesospheric ozone retrievals with the OEM implemented 
directly in ARTS (using the python interface).
As my sensor is not changing much with time, I am wondering if there is a way 
(and if this is worth in terms of computation speed) to reuse the 
sensor_response matrix (FFT channel response, unbinned) for different 
measurements which I think was quite straightforward with Qpack.

I was trying to write multiple calibrated spectra within the y vector as well 
as multiple meas. error cov. (Se and inv) blocks before running the OEM which I 
thought might be the way to go but it seems to treat them as multiple 
measurements of the same ozone profiles instead. Could somebody confirmed if 
this is expected and if yes, is there another way to do this kind of parallel 
OEM retrievals: same sensors, same atmosphere, etc.. just different 
measurements vectors using OEM from ARTS directly ?

Thanks for your help,

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