Difference between revisions of "LBNL-2016: Time-Ordered Data Processing"

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== Time-Ordered Data Processing Birds-of-a-Feather Session: Wednesday, March 9, 9 AM ==  
+
= Time-Ordered Data Processing Birds-of-a-Feather Session: Wednesday, March 9, 9 AM =
  
 
'''Attending''': Julian Borrill, Tom Crawford, Ted Kisner, Kris Gorski, Graca Rocha, Clem Pryke, Nick Harrington, Jesse Treu, Kyle Story, Nathan Whitehorn, Olivier Perdereau, Reijo Keskitalo
 
'''Attending''': Julian Borrill, Tom Crawford, Ted Kisner, Kris Gorski, Graca Rocha, Clem Pryke, Nick Harrington, Jesse Treu, Kyle Story, Nathan Whitehorn, Olivier Perdereau, Reijo Keskitalo
  
−
'''Notes'''
+
== Notes ==
  
−
'''Discussion of TOD scanning simulations with full 4-pi beam'''
+
'''Discussion of TOD scanning simulations'''
−
* do we really get the 4-pi beam at high fidelity?
+
*  Scanning with full 4-pi beam: do we really get the 4-pi beam at high fidelity?
 
** at some level, not the data folks' problem.
 
** at some level, not the data folks' problem.
 
* Are we really going to simulate full TODs, including data that we will eventually cut in the real TOD?
 
* Are we really going to simulate full TODs, including data that we will eventually cut in the real TOD?
Line 32: Line 32:
 
* What about atmosphere?
 
* What about atmosphere?
 
** Moving slab prototypes exist.
 
** Moving slab prototypes exist.
 +
* Loudly stated that TOD sims will not be used in the 3-month timescale forecasting.
 +
** OK, but is there something we can do on the next timescale (~6 months)
 +
** At least agree on common inputs & data formats.
 +
*** That's coming up soon.
 +
 +
'''Time to Pixel Domain'''
 +
* Are preprocessing steps included in instrument?
 +
** In a perfect world, yes.
 +
* Are we discussing mapmaking procedures yet?
 +
** They should all be implementable. Though ML-mapping will be hard from Pole.
 +
 +
'''Implementation Issues'''
 +
* Everything will be driven by data volume.
 +
** First step is to avoid I/O as much as possible.
 +
* How to accommodate two analysis modes (interactive development on small number of timestreams vs. full-TOD MCs)?
 +
** Does a python-based codebase disfavor HPC?
 +
** Not fundamentally, but it would be great to be able to swap in a C/C++ module for the corresponding python module seamlessly.
 +
* DATA FORMAT
 +
** Everyone agrees that Healpix is the right pixel format.
 +
** Use currently implemented cut-sky Healpix format in FITS?
 +
*** That is not using any of the advantages of FITS and incurring many disadvantages.
 +
*** Sounds like we have decided to use hdf5 and take on the job of writing a healpy interface.
 +
* Scalable software used at LBNL
 +
** python-based implementation of LFI control & mapmaking (PyTOAST calling libmadam)
 +
* Will we be able to run different Stage-3 experiments' data through each others' pipelines?
 +
** [raucous laughter ensues]
 +
** Perhaps require that all S3 experiments' data run on their own pipeline and a common pipeline.
 +
** Some consensus achieved that S4 pipeline will be high-level python with some C/C++ under the hood.
 +
 +
'''Outstanding Issues'''
 +
* Back to question of how to implement TOD-level sims? Who is responsible for the instrument model for each instrument?
 +
** Even beyond that, is the framework of simulation we are envisioning even appropriate for (or acceptable to) every instrument?
 +
*** Is there a place we can couple into the BICEP/Keck analysis pipeline?
 +
** How to incorporate scan strategy?
 +
*** From Pole it's pretty obvious; what about 70% of the sky from Atacama? How is AdvACTPol planning on scanning? Action item is to find this out (Julian).
  
 
---------
 
---------
 +
 +
''Word of the day:'' '''Exciting'''
 +
 +
---------
 +
 +
'''Literary allusions'''
 +
 +
''All perfect data sets are identical; each imperfect data set is imperfect in its own way.'' (Anna Karenina)
 +
 +
''First, we kill all the I/O.'' (Henry VI)
 +
 +
----------
  
 
'''Gotcha scorecard'''
 
'''Gotcha scorecard'''
Line 46: Line 93:
 
|Ted
 
|Ted
 
|Nathan
 
|Nathan
 +
|-
 +
|11:20
 +
|Ted, on behalf of Nathan
 +
|Ted
 +
|-
 +
|11:58
 +
|Kris
 +
|All the forecasters
 
|}
 
|}

Latest revision as of 15:06, 9 March 2016

Time-Ordered Data Processing Birds-of-a-Feather Session: Wednesday, March 9, 9 AM

Attending: Julian Borrill, Tom Crawford, Ted Kisner, Kris Gorski, Graca Rocha, Clem Pryke, Nick Harrington, Jesse Treu, Kyle Story, Nathan Whitehorn, Olivier Perdereau, Reijo Keskitalo

Notes

Discussion of TOD scanning simulations

  • Scanning with full 4-pi beam: do we really get the 4-pi beam at high fidelity?
    • at some level, not the data folks' problem.
  • Are we really going to simulate full TODs, including data that we will eventually cut in the real TOD?
    • yes, at least to test automated data cuts.
    • who is going to take on the task of creating this model?
    • we pretty much know how to do it now, unless the fundamental detector and/or readout architecture changes.
  • Do we need to simulate TES & electronics response?
    • Not a high priority. Assume detectors/electronics with funky response will not pass CD.
  • RFI pickup?
    • Impossible to implement in sims without model of pickup.
  • Time-dependent focal plane / optics distortion?
    • Real-world examples to go on from ACT & PB
  • We need scan strategy to be defined to do sims.
    • Is anyone considering using anything but azimuth scans as fast and wide as you can go?

Digression into computing plan

  • Are we really going to use grid computing (rather than parallel processing on large clusters)?
    • Certainly not for anything for which we have to send around real TOD. (I.e., just for sims.)
  • What about data management / delivery from sites?
    • Pole bandwidth barely accommodates SPT-3G and will be unlikely to increase enough to handle S4. Similar issues exist in Atacama.

Return to TOD sims

  • Will there be half-wave plates on S4?
    • Can't rule it out. How do you make a model of non-ideality for a HWP?
  • Are we aiming to have a perfect set of TOD sims by summer or 10 years from now?
    • There will be a profile of what we can simulate. Could in theory have some level of TOD sims by summer.
  • What about atmosphere?
    • Moving slab prototypes exist.
  • Loudly stated that TOD sims will not be used in the 3-month timescale forecasting.
    • OK, but is there something we can do on the next timescale (~6 months)
    • At least agree on common inputs & data formats.
      • That's coming up soon.

Time to Pixel Domain

  • Are preprocessing steps included in instrument?
    • In a perfect world, yes.
  • Are we discussing mapmaking procedures yet?
    • They should all be implementable. Though ML-mapping will be hard from Pole.

Implementation Issues

  • Everything will be driven by data volume.
    • First step is to avoid I/O as much as possible.
  • How to accommodate two analysis modes (interactive development on small number of timestreams vs. full-TOD MCs)?
    • Does a python-based codebase disfavor HPC?
    • Not fundamentally, but it would be great to be able to swap in a C/C++ module for the corresponding python module seamlessly.
  • DATA FORMAT
    • Everyone agrees that Healpix is the right pixel format.
    • Use currently implemented cut-sky Healpix format in FITS?
      • That is not using any of the advantages of FITS and incurring many disadvantages.
      • Sounds like we have decided to use hdf5 and take on the job of writing a healpy interface.
  • Scalable software used at LBNL
    • python-based implementation of LFI control & mapmaking (PyTOAST calling libmadam)
  • Will we be able to run different Stage-3 experiments' data through each others' pipelines?
    • [raucous laughter ensues]
    • Perhaps require that all S3 experiments' data run on their own pipeline and a common pipeline.
    • Some consensus achieved that S4 pipeline will be high-level python with some C/C++ under the hood.

Outstanding Issues

  • Back to question of how to implement TOD-level sims? Who is responsible for the instrument model for each instrument?
    • Even beyond that, is the framework of simulation we are envisioning even appropriate for (or acceptable to) every instrument?
      • Is there a place we can couple into the BICEP/Keck analysis pipeline?
    • How to incorporate scan strategy?
      • From Pole it's pretty obvious; what about 70% of the sky from Atacama? How is AdvACTPol planning on scanning? Action item is to find this out (Julian).

Word of the day: Exciting

Literary allusions

All perfect data sets are identical; each imperfect data set is imperfect in its own way. (Anna Karenina)

First, we kill all the I/O. (Henry VI)

Gotcha scorecard

TIme Deliverer Receiver
9:59 Ted Nathan
11:20 Ted, on behalf of Nathan Ted
11:58 Kris All the forecasters
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