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        ANALYSE\SMOOTH [Arg...]

    SMOOTH copies R into T, then degrades the frequency/velocity  resolution
    of R according to the selected method. If the R buffer also provides As-
    sociated Arrays, the smoothing method is also applied  to  them,  except
    for  the method NOISE where this is not relevant. It is not yet possible
    to provide a custom smoothing method for the Associated Arrays.

    The arguments are used to specify the method:

      - HANNING (no argument, default)
        The new spectrum has twice less channels and twice less  resolution.
        Each  output  channel RY[J] is evaluated from the inputs channels as
        TY[I-1]/2 + TY[I] + TY[I+1]/2.

      - HANNING Width Spacing [Shift]
        The Hann window width is ruled by the "Width" variable, and the out-
        put  channel spacing by the "Spacing" variable. By default, the left
        boundaries of the first input and output channels are  aligned,  but
        user  can  shift  the output grid by any fraction of channel using a
        custom shift ("Shift" variable). All values are  expected  in  lower
        axis  unit. Invoking SMOOTH HANNING 4*res 2*res 0.5*res (where "res"
        is the lower axis resolution) is equivalent to  the  default  SMOOTH
        HANNING (no argument, as described above), except it uses the gener-
        ic (less efficient) engine.

      - GAUSS Width
        Convolves (by multiplication in the Fourier plane) by a gaussian  of
        specified  width  in  current  X units. Because this method does not
        support bad values in the Fourier plane, bad channels  are  interpo-
        lated before use.

      - BOX Nchan
        Averages  Nchan  adjacent  channels to produce a spectrum with Nchan
        less resolution and channels.

      - NOISE Flux Nc
        For each channel, sums at most Nc neighbouring channels until a  to-
        tal  flux  Flux  is  reached in the sum. Then attributes the average
        value (sum divided by number of channels added) to the channel. This
        smoothing is non-uniform, strictly positive, and has an obvious ten-
        dency to produce wings...

Gildas manager 2020-04-07