Star-tpc-l mailing list

[videbaek <videbaek AT bnl.gov>]

Hi

thanks for the forward to the tpc list.
I have two questions/comments

At the meeting Yuri said the error was increased by factor 4. I assume 
the fudgefactor is a multiplier on somethings like sigma**2 ?
I recall way back I questioned why de-convoluted had same erros a 
isoltaed clsuter, so this is actually a good change.




On 2024-10-04 12:38, Frank Geurts wrote:
> > Begin forwarded message:
> > From: Gene Van Buren <notifications AT github.com>
> >
> > Subject: Re: [star-bnl/star-sw] 💥DO NOT MERGE💥 ❗ add new TPC
> > alignment, hit errors and slewing corrections for 2024 (PR #702)
> >
> > Date: October 4, 2024 at 11:05:22 AM CDT
> >
> > To: star-bnl/star-sw <star-sw AT noreply.github.com>
> >
> > Cc: Frank Geurts <geurts AT rice.edu>, Mention
> > <mention AT noreply.github.com>
> >
> > Reply-To: star-bnl/star-sw
> > <reply+AEMNVR6PVQ67TU7N4GHG4NWFBPZUFEVBNHHJEYYC7A AT reply.github.com>
> >
> > @genevb commented on this pull request.
> > -------------------------
> >
> > In StRoot/Sti/StiTrackNodeHelper.cxx [1]:
> >
> > > +    if (tpcHit) {
> > +      if ((tpcHit->detector() == kTpcId || tpcHit->detector() ==
> > kiTpcId)) {
> > +    if (tpcHit->flag() == 2) {
> > +      fudgeFactor = 16.;
> > +    }
> > +      }
> > +    }
> >
> > Yuri suggested that these lines of code in
> > Sti/StiTrackNodeHelper.cxx, modifying some TPC hit errors, might be
> > responsible for the differences seen in nightly tests with this PR
> > vs. DEV for pre-iTPC datasets where the alignment should be
> > unaffected. Processing a few events with and without this bit of
> > code is quite easy, and comparing the log files obviates that the
> > bulk of the difference in track counts does disappear when removing
> > this section of code.
> >
> > However....from looking at the log file, I see that the new
> > alignment scheme appears to alter TPC distortion corrections for
> > these old, pre-iTPC datasets without any change to the
> > reconstruction chain. This is in addition to the modification to TPC
> > distortion corrections ("OSectorAlign") that Yuri wants to impose
> > with the "CorrZ" chain option he has proposed for iTPC-era datasets
> > for which I have expressed an interest in seeing a justification
> > (through data, not anecdotally).
> >
> > < StMagUtilities::XTWIST        =  -0.38 mrad
> > < StMagUtilities::YTWIST        =  0.25 mrad
> > ---
> > > StMagUtilities::XTWIST        =  0 mrad
> > > StMagUtilities::YTWIST        =  0 mrad
> >
> > < StMagUtilities::WestClock     =  -0.43 mrad
> > ---
> > > StMagUtilities::WestClock     =  0 mrad
> >
> > I do not recall this being discussed before, neither in the context
> > of pre-iTPC datasets, nor with the new alignment. If the TPC
> > alignment calibration was truly performed without any correction for
> > the distortions due to the misalignment of the E and B fields
> > (represented by the XTWIST & YTWIST numbers), I have significant
> > concerns about this TPC alignment. Hopefully I am missing something
> > and this is not the case.
> > -------------------------
> >
> > I have placed output of the nightly test without this particular
> > code (but including the rest of this PR) at this location:
> >
> > This PR minus hit error change :
> /star/rcf/test/gitdev/daq_sl302.stica/Mon/year_2016/AuAu200_production_2016_64bit/
> > This is for comparison with other iterations:
> >
> > DEV :
> /star/rcf/test/dev/daq_sl302.stica/Sat/year_2016/AuAu200_production_2016_64bit/
> > This PR :
> /star/rcf/test/gitdev/daq_sl302.stica/Tue/year_2016/AuAu200_production_2016_64bit/
> > This PR before the Sept. 11th commits :
> /star/rcf/test/gitdev/daq_sl302.stica/Wed/year_2016/AuAu200_production_2016_64bit/
> > I am making note of the last two in particular because Yuri's study
> > involved the output from the last one (those jobs were started on
> > September 11th before the time of Yuri's last commits), even though
> > data with those commits was available. (Side note, please pay no
> > heed to the "Tue" or "Mon" in the gitdev paths, as I moved files
> > there from other days to avoid them being over-written.) I will note
> > that I didn't see any effective impact of those commits on this
> > particular test's track counts (i.e. the last two outputs may be
> > identical).
> >
> > —
> > Reply to this email directly, view it on GitHub [2], or unsubscribe
> > [3].
> > You are receiving this because you were mentioned.Message ID:
> > <star-bnl/star-sw/pull/702/review/2348366613 AT github.com>
>
>
>
> Links:
> ------
> [1] https://github.com/star-bnl/star-sw/pull/702#discussion_r1787896945
> [2] 
> https://github.com/star-bnl/star-sw/pull/702#pullrequestreview-2348366613
> [3] 
> https://github.com/notifications/unsubscribe-auth/AEMNVR3S4SFYAFRVTDX3AF3ZZ24EFAVCNFSM6AAAAABMGT4I5OVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMZDGNBYGM3DMNRRGM

--
Flemming Videbaek
senior scientist, emeritus
videbaek @ bnl.gov
Brookhaven National Lab
Physics Department
Bldg 510D
Upton, NY 11973

phone: 631-344-4106
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