Call: FIT_MATHIESON

reference

Should contain on entry the Histogram which is to be fitted. The argument is not modified by the call.

[Mandatory argument if the histogram format is used.]

x

Should contain on entry a 1-dimensional Matrix in which the abscissa are stored of the points on which the fit is to be performed.

This vector should have the same size as y.

The argument is not modified by the procedure.

[Mandatory argument if the matrix format is used.]

y

Should contain on entry a 1-dimensional Matrix in which the function values are stored of the points on which the fit is to be performed.

This vector should have the same size as x.

The argument is not modified by the procedure.

[Mandatory argument if the matrix format is used.]

Should contain on entry the errors on the function values. These errors can either be specified in the form of a single Number, which is interpreted as a common error for all function values, or in the form of a 1-dimensional Matrix of errors for each point separately.

If a Matrix type argument is used, then it must have the same length as x and y.

The argument is not modified by the procedure.

[Mandatory argument if the matrix format is used.]

distance

The distance between anode and cathode. The anode is assumed to be the place where the avalanches take place. The strip width is derived from the bin width of the input histogram.

This parameter is mandatory, and should be entered in cm.

centre

If the fit is successful, then this parameter contains on return the reconstructed track location in cm. The coordinate system is the same as the horizontal axis of the input histogram.

This parameter should be modifiable and its value prior to the call is not used. Any matrix, histogram or string associated with it before the call is lost.

norm

Contains on return, if the fit is successful, the normalisation of the fitted Mathieson distribution.

This parameter should be modifiable and its value prior to the call is not used. Any matrix, histogram or string associated with it before the call is lost.

k3

If the FITK3 option is specified, then this argument contains on return of a successful fit the K3 parameter that matches best the histogram. If a value is given on entry, then this value will be used as starting point for the fit. Otherwise, an initial value of 0.5 is taken.

The argument must in this case be modifiable. Any matrix, histogram or string associated with it before the call is lost.

If the NOFITK3 option is specified, then this argument must contain on entry your preferred value of K3. The argument is then not modified and the corresponding error is set to 0.

error

The errors returned are the square roots of the diagonal elements of the covariance matrix, multiplied by a correction factor equal to:

\&radic;(\&chi;\&sup2;/(#points - #parameters))

This correction factor is equal to 1 if the errors to the data points have been assigned correctly.

These arguments must be modifiable, that is, they can neither be constants nor expressions.

options

The options string may contain the keywords listed in the table below. The keywords should be separated by blanks or commata. Additional text may be added - no error message will be issued if unrecognised keywords are used.

Option	Meaning	Defaults
`EQUAL`	Assume equal weight of all points	Default
`FITK3`	Fits the K3 parameter	Default
`NOFITK3`	Keep the K3 parameter fixed	Not default
`NOPLOT`	Don't plot the histogram and fit	Default
`NOPRINT`	Don't print details during the fit	Default
`PLOT`	Plot the histogram with fit	Not default
`POISSON`	Assume Poisson errors	Not default
`PRINT`	Print details during the fit	Not default

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Formatted on 21/01/18 at 16:55.