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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.]


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:
     sqrt(chi**2/(#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 0105-10-15 at 17:17.