[daip] [!11175]: AIPS - KRING dual-pol solutions on single-pol stations (31DEC17 and previous versions)

[Kazunori Akiyama]

Kazunori Akiyama updated #11175
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KRING dual-pol solutions on single-pol stations (31DEC17 and previous versions)
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           Ticket ID: 11175
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/11175
                Name: Kazunori Akiyama
       Email address: kazu at haystack.mit.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 26 October 2017 06:37 PM
             Updated: 26 October 2017 06:37 PM
           Reply due: 30 October 2017 06:37 PM (4d 0h 0m)
      Resolution due: 22 July 2020 12:00 AM (999d 5h 23m)

Dear Eric,I found an issue on KRING, for which I think this time is real.We have tried KRING for fring fitting, since EHT data are really massive (32 Gbps data) and FRING has been very computationally expensive for EHT data. KRING very effectively worked thanks to really high SNRs enhanced by ALMA, although simulteneously we found an issue on SN tables from KRING.EHT data have a dual polarization in most of the stations, but some stations only have a single polarization. We have found that KRING can found solutions on such single-pol stations, but stations are automatically flagged after CLCAL even if we can see gain solutions in SN-table-applied (i.e. CLCALed) CL tables.I export SN tables from KRING and also those from other tasks (e.g. ACCOR, ACSCL, FRING) that can keep single-pol stations. I found that other tasks put NaN values on REAL/IMAG columns of SN tables when data do not exist, while they put a positive value on WEIGHT columns probably for distinguishing no data issues from solution failures on existing data. However, on the other hand, KRING will put -1 on WEIGHT columns if data do not exist. AIPS seems to kill all data on a station if all of its gains in CL tables have WEIGHT < 0 at a single polarization (which makes a sense), causing that all single-pol stations are practically flagged after KRING.I confirmed this happened in the latest 31DEC17 and also 31DEC16. We can tentatively fix this issue by editing SN tables manually, but I suppose that this issue can be fixed easily. I would appreciate if you can fix this issue in 17DEC31.Anway, thank you very much for continuous supports on EHT data reduction!Best regards,KazuP.S.Is it possible to CC following people to this ticket?They have worked on AIPS as well, and would follow this issue.Lindy Blackburn: lblackburn at cfa.harvard.eduThomas Krichibaum: tkrichbaum at mpifr-bonn.mpg.deKevin Koay: jykoay at asiaa.sinica.edu.tw Michael Janssen: m.janssen at astro.ru.nlSara Issaoun: s.issaoun at astro.ru.nlGuangyao Zhao: guangyao.ac.cn at gmail.com

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