Environment Variables

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8.3.1 Environment Variables

The asaprc environment variables are stored in the Python dictionary sd.rcParams in CASA. This contains a number of parameters that control how ASAP runs, for both tools and tasks. You can see what these are set to by typing at the CASA prompt:

CASA <2>: sd.rcParams
Out[2]:
{’insitu’: True,
’plotter.colours’: ’’,
’plotter.decimate’: False,
’plotter.ganged’: True,
’plotter.gui’: True,
’plotter.histogram’: False,
’plotter.linestyles’: ’’,
’plotter.panelling’: ’s’,
’plotter.papertype’: ’A4’,
’plotter.stacking’: ’p’,
’scantable.autoaverage’: True,
’scantable.freqframe’: ’LSRK’,
’scantable.save’: ’ASAP’,
’scantable.storage’: ’memory’,
’scantable.verbosesummary’: False,
’useplotter’: True,
’verbose’: True}

The use of these parameters is described in detail in the ASAP Users Guide.

These parameters can be changed through the sd.rc function. Use is described in help sd.rc:

CASA <3>: help(sd.rc)
Help on function rc in module asap:

rc(group, **kwargs)
    Set the current rc params.  Group is the grouping for the rc, eg
    for scantable.save the group is ’scantable’, for plotter.stacking, the
    group is ’plotter’, and so on.  kwargs is a list of attribute
    name/value pairs, eg

      rc(’scantable’, save=’SDFITS’)

    sets the current rc params and is equivalent to

      rcParams[’scantable.save’] = ’SDFITS’

    Use rcdefaults to restore the default rc params after changes.

Important Note:
User must use sd.rcParams[scantable.storage’]=’disk’ with care when you call any tool level functions since some functions may overwrite original data even if you set sd.rcParams[’insitu’]=False, which tells the system not to overwrite original data (in contrast, setting sd.rcParams[’insitu’] to True forces to overwrite original data). Relevant methods, which may overwrite original data in the above case, are as follows:

sd.average_time
sd.merge
four operations (+, -, *, /) of sd.scantable instance with scalar or array
sd.scantable.add
sd.scantable.clip
sd.scantable.flag
sd.scantable.flag_nans
sd.scantable.flag_row
sd.scantable.scale
sd.scantable.recalc_azel
any setter functions of sd.scantable class (both set_xxx and _setxxx functions)

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