## Command FSUM

Parameters Defaults
FSUM windows
/
DISPLAY
CONDITIONS
LOOP
GRAPHIC
NET
TOTAL
FWHM
CONFIDENCE(co) 0.683
STORE(st)
**Purpose**
Compute sum and moments.
**Function**
Compute sum and moments of raw (input) or net (input minus fit) data.
Output results on terminal, current picture or global parameter.
**Example**
**
FSUM a,b,c / NET FWHM STORE( p(3,1) )
**
Compute the moments of the net data (2nd moment expressed as FWHM)
in the three display windows **A,B,C**.
Results are stored in global parameter array **p()**.
p(3,1), p(3,2), ... receive moments of window A,
p(4,1), p(4,2), ... receive moments of window B, and
p(5,1), p(5,2), ... receive moments of window C.

## Parameter WINDOWS(wdws)

List of windows, interpreted as follows:
window item = number: condition,
window item = letter: display window,
window item = #: temporary window
window item = *: all fit windows.

## Parameter DISPLAY

All display windows are integrated

## Parameter CONDITIONS

All conditions are integrated

## Parameter LOOP

Windows are prompted in a loop. See also command FWINDOWS

## Parameter GRAPHIC

Write results into current picture

## Parameter NET

Sum and moments of the net data are calculated, i.e. the values of the fit function
are subtracted from the input data.

## Parameter TOTAL

Sum and moments of the input data are calculated.

## Parameter FWHM

The variance (second moment) is converted into an FWHM value according to
**FWHM = sqrt( 8*log(2) * n / (n-1) ) * variance**,
where **n** is the number of data points.
The skewness (third moment) is expressed in terms of the square root of the variance.

## Parameter CONFIDENCE(co)

For **0 < co < 1** the evaluated function errors correspond to confidence limit **co**.
Usually **co = 0.683** corresponds to the propagated error bars of the fitted input data.

## Parameter STORE(p)

Name of a floating point global parameter array to receive the calculated moments.
Storing starts at the specified index, or, if the index is omitted,
at the first element. If the array is 1-dimensional only sums are returned,
otherwise the data are stored columnwise, containing the following items
per row (sufficient bounds provided):
x-limits, sum, error, mean, variance (or FWHM), skewness.