= Changes/atlod =

 ||atlod||            ||           ||      ||
 ||Item || Difficulty || Milestone || Time ||
 ||SamplerStatistics    || easy || 6 || 1d ||
 ||DataSizeLimits       || easy || 6 || 2d ||
 ||IdentifyParentWindow || moderate || 8 || 2*5d ||
 ||FlaggingWithinATLOD - basics  || easy || 6 || 5d ||
 ||FlaggingWithinATLOD - autoflagging || moderate || 9 || 4*5d ||
 ||MoreSelectionOptions || easy || 6 || 5d ||

 [wiki:SYSCALRecordChanges]::
  The SYSCAL records will change from their current form.
    SamplerStatistics::
      we no longer use these. So we need to avoid checking for them with CABB-type data.

    StorageOfSYSCALData::

     Now that there are no sampler statistics, we need a different way of carrying along [wiki:Glossary/Tsys Tsys] and  
     [wiki:Glossary/XYPhase XYPhase] data than we have at present. 
     At present there are 24 scalar values of Tsys (6 antennae * 2 polarizations * 2 IFs) written into every integration, and
     12 (6 ant. * 2 IFs) of XYPhase.

     In the new system there will likely be a spectrum of each, in the form of autocorrelations.
     Tsys is formed from the XX and YY polarisations of the autocorrelations, with the noise diode on and off;
     XYPhase from the XY (or its conjugate, YX) with the diode on and off.

 DataSizeLimits::
  we need to check for size limits on the data dimensions - number of windows, channels, etc

 [wiki:XYPhaseCalibration]::
  instead of a single (instrumental) XY phase term, we will now get all the autocorellations.
  This has the potential to greatly inflate the data volume.

 IdentifyParentWindow::
  Each spectral window output by the correlator can have some [wiki:Glossary/ZoomBands ZoomBands] defined.
  We think that it will be necessary to keep track of each window's parent window. There should only be 0 or 1 parents.

  Whether it is necessary to keep track of the children of a particular band is unclear.

 [wiki:FlaggingWithinATLOD]::
  [http://www.atnf.csiro.au/computing/software/miriad/doc/atlod.html atlod] does a qualitatively different type of 
  flagging to other parts of Miriad; it drops data from the output instead of just marking it as bad.

  There are two possible types of flagging-related changes.
  * removal of [wiki:Glossary/Birdies birdies] - there are likely to be some new ones
  * possibly using the [Glossary/AutoCorrelations autocorrelations] to flag data affected by interference.

 MoreSelectionOptions::
  Probably people will want to atlod just a subset of the data, not the whole thing. 
  This requires more selection options than just 'ifsel'.



[/trac/miriad4cabb Wiki Home]