CALL: FIT_GAUSSIAN
The histogram is referenced via a global variable that has usually
been returned by a call to BOOK_HISTOGRAM or GET_HISTOGRAM. This
argument may also be an expression that results in a histogram.
The argument is not modified on return.
A 1-dimensional vector that contains the abscissa of the
points on which the fit is to be performed.
This vector should have the same size as y.
A 1-dimensional vector that contains the function values
of the points on which the fit is to be performed.
This vector should have the same size as x.
Either a scalar which is interpreted as a common error
on all function values (y) or a 1-dimensional vector of
the same length as x and y and which contains for each
point the error in the function value.
The contents of the fitted Gaussian.
There is no need to initialise this argument - the initial
value for the fitting procedure is set to the sum of the
histogram or Y array.
This argument must be modifiable, i.e. it can not be a constant
nor an expression.
The central value of the fitted Gaussian.
There is no need to initialise this argument - the initial
value for the fitting procedure is set to the mean of the
histogram or arrays.
This argument must be modifiable, i.e. it can not be a constant
nor an expression.
The standard deviation of the fitted Gaussian.
There is no need to initialise this argument - the initial
value for the fitting procedure is set to the RMS of the
histogram or arrays.
This argument must be modifiable, i.e. it can not be a constant
nor an expression.
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.
Errors are only returned upon request. The corresponding
arguments must be modifiable, that is, they can neither be
constants nor expressions.
The options string may contain the keywords listed in the table
below. The keywords should be separated by blanks or commas.
Additional text may be added - no error message will be issued
if unrecognised keywords are used.
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Option Meaning Defaults
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EQUAL Assume equal weight of all points 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 Default
PRINT Print details during the fit Not default
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Keyword index.
Formatted on 10/11/98.