Miriad% inp csdi
  Task:   csdi
  map      =  
  model    =  
  beam     =  
  out      =  
  gain     =  
  options  =  
  cutoff   =  
  niters   =  
  region   =  
  clip     =
csdi% help
Task:    csdi

Responsible: Bob Sault

         CSDI is a MIRIAD task that performs the complex Steer Clean 
         algorithm, which takes a Stokes Q and U dirty map and beam, 
         and produces two output maps that consist of the Stokes Q and  
         Stokes U Clean components.
         These outputs can be input to RESTOR to produce a "clean" image.  
         The model could be from a previous CSDI run, or from other
         deconvolution tasks.

         Full details of the algorithm are found in: 
         Pratley & Johnston-Hollitt, “An improved method for polarimetric 
         image restoration in interferometry", MNRAS, 2016. ArXiv: 1606.01482. 
         Please acknowledge this work in publications using the code.

Keyword: map
         The input Stokes Q and U dirty maps, which should have units of
         Jy/beam. No default.

Keyword: model
         Initial models of the Stokes Q and U deconvolved images. This  
         could be the output from a previous run of CSDI, or the output of
         other deconvolution tasks. It must have flux units of
         Jy/pixel. The default is no model (i.e. a zero map).

Keyword: beam
         The input of Stokes I, Q or U dirty beam. No default

Keyword: out
         The names of the Stokes Q and U output map. The units of the  
         output will be Jy/pixel.  The files will contain the contribution
         of the input models.  They should have a different name to the 
         input model (if any).  They can be input to RESTOR or CSDI (as a
         model,to do more cleaning)   

Keyword: gain
         The minor iteration loop gain. Default is 0.1.

Keyword: options
         Extra processing options. Several can be given, separated
         by commas. Minimum match is used. Possible values are:
           asym      The beam is asymmetric.  By default CLEAN assumes
                     the beam has a 180 degree rotation symmetry, which
                     is the norm for beams in radio-astronomy.
           pad       Double the beam size by padding it with zeros. This
                     will give you better stability if you are daring enough 
                     to CLEAN an area more than half the size 
                     (in each dimension) of the dirty beam.

Keyword: cutoff
         CLEAN finishes either when the absolute maximum residual falls
         below CUTOFF, or when the criteria described below is
         satisfied. The default CUTOFF is 0. It is recommended that the
         cutoff is 3 times the rms noise of Stokes Q or U.

Keyword: niters
         The maximum number of minor iterations.  The default is 250,
         which is too small for all but the simplest of images.  CLEAN
         will stop when either the maximum number of iterations is
         performed, or the cutoff (see above) is reached.

Keyword: region
         This specifies the region to be Cleaned.  See the help on
         "region" for more information.  The default is the largest
         region that can be deconvolved safely.

Keyword: clip
         This sets the relative clip level in Steer mode. Values are
         typically 0.75 to 0.9. The default is image dependent.

         di.for,v 1.1 2016/06/12 04:11:06 wie017 Exp $
csdi%