One and two-dimensional distributions

CALL HFITH (ID,FUN,CHOPT,NP,*PARAM*,STEP,PMIN,PMAX,SIGPAR*,CHI2*)

Action: Fits a given parametric function to the contents of a 1- or 2-dimensional histogram, and optionally superimposes it to the 1-dimensional histogram when editing.

Input parameters:

ID

Histogram identifier.

FUN

Parametric function (to be declared EXTERNAL, see )
Can be defined interactively in the interactive version (see PAW manual)

CHOPT

Character variable specifying the desired options.

'B'

Some or all parameters are bounded. The arrays STEP, PMIN and PMAX must be specified. By default all parameters vary freely.

'D'

The user provides the derivatives of the function analytically with the user routine HDERIV. By default derivatives are computed numerically.

'E'

Perform a detailed error analysis using the MINUIT routines HESSE and MINOS

'F'

Force storing of the result of the fit bin by bin with the histogram for an any-dimensional histogram.

'K'

'KM' means: do to reset the parameters of Application HMINUIT.

'L'

Use the logaritmic Likelihood fitting method. By default the chisquared method is used.

'M'

Invoke interactive MINUIT.

'N'

The results of the fit are not stored bin by bin with the histogram. By default the function is calculated at the centre of each bin in the specified range.

'Q'

Quiet mode. No printing.

'R'

Fit a Restricted area of a 1-D or 2-D histogram. The limits for the fit are given using in the vector IQUEST is in the communication common /QUEST/IQUEST(100), as follows:
  IFXLOW = IQUEST(11) specifies the lower limit in X,
IFXUP = IQUEST(12) specifies the upper limit in X,
IFYLOW = IQUEST(13) specifies the lower limit in Y (2-D),
IFYUP = IQUEST(14) specifies the upper limit in Y (2-D).

'U'

User function value is taken from /HCFITD/FITPAD(24),FITFUN,   see section . All calculations are performed in double precision.

'V'

Verbose mode. Results are printed after each iteration. By default only final results are printed.

'W'

Set the event weights equal to one. By default weights are taken according to statistical errors.

NP

Number of parameters (NP$\leq$25).

PARAM

Array of dimension NP with initial values for the parameters.

STEP

Array of dimension NP with initial step sizes for the parameters ('B' option only).

PMIN

Array of dimension NP with the lower bounds for the parameters ('B' option only).

PMAX

Array of dimension NP with the upper bounds for the parameters ('B' option only).

Output parameters:

PARAM

Array of dimension NP with the final fitted values of the parameters.

SIGPAR

Array of dimension NP with the standard deviations on the final fitted values of the parameters.

CHI2

Chisquared of the fit.