Documentation on maxen

Task: maxen
Purpose: Maximum Entropy deconvolution
Categories: deconvolution

        MAXEN is a MIRIAD task which 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 Users Manual
        for instructions on how to specify this. The default is the inner
        quarter of all planes.

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 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 better stability if you are daring enough
                     to deconvolve more than the inner quarter of the dirty
                     image.