class TFitEditor: public TGMainFrame

TFitEditor

Allows to perform, explore and compare various fits.

To display the new Fit panel interface right click on a histogram
or a graph to pop up the context menu and then select the menu
entry 'Fit Panel'.

"General" Tab

The first set of GUI elements is related to the function choice
and settings. The status bar on the bottom provides information
about the current minimization settings using the following
abbreviations:
LIB - shows the current choice between Minuit/Minuit2/Fumili
MIGRAD or FUMILI points to the current minimization method in use.
Itr: - shows the maximum number of iterations nnnn set for the fit.
Prn: - can be DEF/VER/QT and shows the current print option in use.

"Predefined" combo box - contains a list of predefined functions
in ROOT. The default one is Gaussian.

"Operation" radio button group defines selected operational mode
between functions: NOP - no operation (default); ADD - addition
CONV - convolution (will be implemented in the future).

Users can enter the function expression in a text entry field.
The entered string is checked after Enter key was pressed. An
error message shows up if the string is not accepted. The current
prototype is limited and users have no freedom to enter file/user
function names in this field.

"Set Parameters" button opens a dialog for parameters settings.

"Fit Settings" provides user interface elements related to the
fitter. Currently there are two method choices: Chi-square and
Binned Likelihood.

"Linear Fit" check button sets the use of Linear fitter is it is
selected. Otherwise the option 'F' is applied if polN is selected.
"Robust" number entry sets the robust value when fitting graphs.
"No Chi-square" check button sets ON/OFF option 'C' - do not
calculate Chi-square (for Linear fitter).

Fit options:
"Integral" check button switch ON/OFF option 'I' - use integral
of function instead of value in bin center.
"Best Errors" sets ON/OFF option 'E' - better errors estimation
using Minos technique.
"All weights = 1" sets ON/OFF option 'W' - all weights set to 1,
excluding empty bins and ignoring error bars.
"Empty bins, weights=1" sets ON/OFF option 'WW' -  all weights
equal to 1, including  empty bins, error bars ignored.
"Use range" sets ON/OFF option 'R' - fit only data within the
specified function range with the slider.
"Improve fit results" sets ON/OFF option 'M' - after minimum is
found, search for a new one.
"Add to list" sets On/Off option '+'- add function to the list
without deleting the previous.

Draw options:
"SAME" sets On/Off function drawing on the same pad.
"No drawing" sets On/Off option '0'- do not draw function graphics.
"Do not store/draw" sets On/Off option 'N'- do not store the
function, do not draw it.

Sliders settings are used if option 'R' - use range is active.
Users can change min/max values by pressing the left mouse button
near to the left/right slider edges. It is possible o change both
values simultaneously by pressing the left mouse button near to its
center and moving it to a new desire position.

"Minimization" Tab

"Library" group allows you to use Minuit, Minuit2 or Fumili
minimization packages for your fit.
"Minuit" - the popular Minuit minimization package.
"Minuit2" - a new object-oriented implementation of Minuit in C++.
"Fumili" - the popular Fumili minimization package.

"Method" group has currently restricted functionality.
"MIGRAD" method is available for Minuit and Minuit2
"FUMILI" method is available for Fumili and Minuit2
"SIMPLEX" method is disabled (will come with the new fitter design)

 "Minimization Settings' group allows users to set values for:        //
"Error definition" - between 0.0 and 100.0  (default is 1.0).
"Maximum tolerance" - the fit relative precision in use.
"Maximum number of iterations" - default is 5000.

Print options:
"Default" - between Verbose and Quiet.
"Verbose" - prints results after each iteration.
"Quiet" - no fit information is printed.

Fit button - performs a fit.
Reset - resets all GUI elements and related fit settings to the
default ones.
Close - closes this window.

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