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Created by Jens Kroeger@jekroegeOwner11 of 11 tasks completed11/11 tasks

Detector: update conversion from local coordinates to pixel counts etc.

While working on the improvement of the clustering and DUT association, I realized that we're currently now completely consistent with how we're using the coordinates in pixel units.

In most places a pixel has the sub-pixel range [col, col+1], accordingly for the row. But then we have to add 1/2*pitch every now and again to make sure the conversion <int> to <double> is correct. This is prone to errors and we're making some errors here.

So after a discussion with @simonspa, the conclusion was that it's more natural to change it to [col-1/2,col+1/2].

Advantage:

  • We don't have to add 1/2 pitch anywhere: but the conversion from int to double is much safer now: double col = static_cast<double>(col_int) and nothing can go wrong.

Disadvantage:

  • pixel 0 extends into the negative range: [-0.5,0.5), all others are positive.
  • From double to int previously was simply int col = floor(dbl_col) and it is now int col = floor(dbl_col) + pitch/2 but this is hardly ever used whereas the opposite case (described above) is used all the time.

We only have to make sure we adjust all the affected histograms (range from -0.5 to Npixels-0.5 now and remove all the +1/2*pitch.

Here's a list of all modules being affected/not affected by this change. The affected ones should be those which make use of in-pixel information. All histograms like hitmaps which are filled only with int values can stay the same.

Affected (will have to look closer)

  • AnalysisCLICpix
  • AnalysisDUT
  • AnalysisEfficiency
  • AnalysisTelescope
  • AnalysisTimingATLASpix
  • Clustering4D
  • ClusteringSpatial
  • EtaCalculation
  • EtaCorrection
  • Tracking4D
  • TrackingSpatial

Not affected

  • AlignmentDUTResidual
  • AlignmentMillepede
  • AlignmentTrackChi2
  • AnalysisPowerPulsing
  • Dummy
  • EventLoaderATLASpix
  • EventLoaderCLICpix
  • EventLoaderCLICpix2
  • EventLoaderEUDAQ
  • EventLoaderEUDAQ2
  • EventLoaderMuPixTelescope
  • EventLoaderTimepix1
  • EventLoaderTimepix3
  • ImproveReferenceTimestamp
  • MaskCreator
  • MaskCreatorTimepix3
  • Metronome
  • OnlineMonitor
  • Prealignment
  • TestAlgorithm
  • TreeWriter
Edited by Jens Kroeger