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# stub function definition file for docstring parsing
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[docs]def uvsub(vis, reverse=False):
r"""
Subtract/add model from/to the corrected visibility data.
[`Description`_] [`Examples`_] [`Development`_] [`Details`_]
Parameters
- vis_ (string) - Name of input visibility file (MS)
- reverse_ (bool=False) - reverse the operation (add rather than subtract)
.. _Description:
Description
This task subtracts the model visibilities in the MODEL_DATA
column of a MeasurementSet from the corrected visibilities in the
CORRECTED_DATA column. The MODEL_DATA column can either be the
scratch column or a virtual one. The residuals after subtraction
are placed in the CORRECTED_DATA column. If the parameter
*reverse* is set to True, the process is reversed and the model
will instead be added to the corrected data. The DATA column is
left untouched. If the MeasurementSet has no CORRECTED_DATA
column, one is created and the content of the DATA column is
copied into it ahead of the **uvsub** process.
.. note:: **NOTE**: **uvsub** does the subtraction over the whole MS. The
model visibilities are usually populated by the tasks
**clean**/**tclean**, **ft** and **setjy**. If only a
subsection of the MS was used in these tasks (e.g., when
selecting *field* or *spw* in **clean** or **ft**), then only
this subset of model visibilities will be populated and the
**uvsub** operation will give expected results only for this
subsection of the MS. The remainder of the MS will get the
CORRECTED_DATA added/subtracted with whatever was there
originally in the MODEL_DATA column (on initialization, the
model visibilities are 1 for parallel hand and 0 for cross
hand).\\
.. warning:: **WARNING: ** Currently, **uvsub** will not work if the
frequency axis is different between the MS file the model is
derived from and the MS file you are subtracting from. Please
use **cvel2** to regrid the frequency axis of the MS to match
that of the model.
See also the CASA Docs chapter pages on `Subtracting and Adding
Model
Visibilities <../../notebooks/uv_manipulation.ipynb>`__.
.. rubric:: Parameter descriptions
*vis*
Name of input visibility file (MS).
*reverse*
Reverse the operation (add rather than subtract). Default is
reverse=False.
.. _Examples:
Examples
To subtract model visibilities stored in the MODEL_DATA column
from the corrected visibility data in the CORRECTED_DATA column of
a MeasurementSet, and write the residual visibilities back into
the CORRECTED_DATA column:
::
uvsub(vis='filename.ms', reverse=False)
.. _Development:
Development
No additional development details
.. _Details:
Parameter Details
Detailed descriptions of each function parameter
.. _vis:
| ``vis (string)`` - Name of input visibility file (MS)
.. _reverse:
| ``reverse (bool=False)`` - reverse the operation (add rather than subtract)
"""
pass