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Basic Information on maxen


Task: maxen
Purpose: Maximum Entropy deconvolution
Categories: deconvolution

        MAXEN is a MIRIAD task that performs a maximum entropy
        deconvolution algorithm on a cube.

Key: map
        The input dirty map, which should have units of Jy/beam.
        No default.

Key: beam
        The input dirty beam. No default

Key: model
        An initial estimate of the deconvolved image.  For point
        sources, giving a good initial model may help convergence.  In
        principle, this only helps convergence, but should not affect
        the final solution.  The model could be the output from a
        previous run of MAXEN or any other deconvolution task.  It must
        have flux units of Jy/pixel.  The default is a flat estimate,
        with the correct flux.

Key: default
        The default image.  This is the image that the final solution
        will tend towards.  The final result will be influenced by this
        default if the constrains that the data put on the solution are
        weak.  The default is a flat estimate, with the correct flux.

Key: out
        The name of the output map.  The units of the output will be
        Jy/pixel.  It can be input to RESTOR, MAXEN (as a model, to
        continue the deconvolution process), or to SELFCAL (for self-
        calibrating visibility data).

Key: niters
        The maximum number of iterations. The default is 20.

Key: region
        This specifies the region to be deconvolved.  See the User
        Manual for instructions on how to specify this.  The default is
        the largest centered region that it is safe to deconvolve.

Key: measure
        The entropy measure to be used, either "gull" (-p*log(p/e)) or
        "cornwell" (-log(cosh(p)) -- also called the maximum emptyness
        criteria).

Key: tol
        Tolerance of solution. There is no need to change this from the
        default of 0.01.

Key: q
        An estimate of the number of points per beam. MAXEN can usually
        come up with a pretty good, image dependent estimate.

Key: rms
        The rms noise, in Jy/beam, in the dirty map. No default. The
        convergence and behavior of MAXEN depends strongly on the value
        of this parameter.

Key: flux
        The flux of the source. If FLUX is given as a positive
        number, then the resultant image is constrained to have this
        flux. If FLUX is negative, then abs(FLUX) is used as an estimate
        of the source flux only and the actual flux is allowed to vary.
        If FLUX=0, then MAXEN makes a guess at the source flux.  Default
        is FLUX=0, though you should give MAXEN more information if at
        all possible.  On the other hand, a bad value here can cause
        MAXEN to blow up.

Key: options
        Task enrichment parameters.  Several can be given, separated by
        commas.  Minimum match is used. Possible values are:
          quiet      Do not give any messages during iterations.  The
                     default is to give a one line message at each
                     iteration.
          verbose    Give lots of messages during the iterations.  The
                     default is to give a one line message at each
                     iteration.
          asym       The beam is asymmetric.  By default MAXEN assumes
                     the beam has 180 deg rotation symmetry, which is
                     the norm for beams in radio-astronomy.
          pad        Double the beam size by padding it with zeros.
                     This will give better stability if you are daring
                     enough to deconvolve more than the inner quarter of
                     the dirty image.
 
Revision: 1.7, 2016/03/18 03:25:44 UTC

Generated by miriad@atnf.csiro.au on 21 Jun 2016