SOLVE AMPLITUDE

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SOLVE AMPLITUDE

            CLIC\SOLVE AMPLITUDE  [/PLOT] [/BREAK kind time [kind time ...]
            [/POLYNOMIAL [degree]] [/WEIGHT] [/RESET]

        This command fits a mathematical function into the measured amplitude of
        the  sources  in  the current index (presumably calibrators).  This data
        must have been selected and plotted in axes : SET X TIME and SET  Y  AM-
        PLITUDE for the baselines and bands of interest, specified by the corre-
        sponding SET commands. The calibration function is kept in memory.  Com-
        mand  STORE  AMPLITUDE should be used next to store this function in the
        header of source observations, after a change in the index to select the
        appropriate scans.

        SOLVE  AMPLITUDE  internally  and  temporarily  resets  SET AMPLITUDE to
        SCALED.

        In antenna mode (selected by SET AMPLITUDE ANTENNA), the averaged  phase
        and  amplitude  closures  are computed, as well as their standard devia-
        tions. The phase closures should be close to zero, while  the  amplitude
        closures  should  be  close to 100%. Strong deviations of amplitude clo-
        sures from 100% are an indication of amplitude loss on  long  baselines,
        due to phase decorrelation during the time averaging. The fit then shows
        strong systematic errors; if this occurs, baseline based calibration  of
        the amplitudes might be preferred.

        Option  /PLOT  will  plot  the fitted curve over the data. Option /RESET
        will reset the calibration curve in memory.

        Fitted curves may be of two kinds:

          - Cubic splines (the default).  By default knots are regularly  spaced
            with  an  interval between knots set by the SET STEP command.  Addi-
            tional knots may be introduced with the  option  "/BREAK  kind  time
            [kind  time  ...]"   which  introduces  a  break at abscissa 'time';
            'kind' is an integer in the range 0-3; 0 means that a  discontinuity
            will  be present, 1 that the first derivative will be discontinuous,
            and so on.  Several breaks may be introduced. The program  will  de-
            tect  an  error  if  too many breaks are introduced, compared to the
            density of data points.

          - Polynomial curves may be used instead.   For  this  the  option  is:
            /POLYNOMIAL  [degree]  indicating  the degree of the polynomial (de-
            fault 0).

        Normally the data points are all assigned the same weight for  the  fit.
        With option /WEIGHT, the data points are weighted according to their er-
        rors.