NESC9533 CURVE,LSFIT.

1. NAME OR DESIGNATION OF PROGRAM:  CURVE,LSFIT.

3. DESCRIPTION OF PROGRAM OR FUNCTION

CURVE and LSFIT are interactive programs designed to obtain the best data fit to an arbitrary curve. CURVE finds the type of fitting routine which produces the best curve. The types of fitting routines available are linear regression, exponential, logarithmic, power, least squares polynomial, and spline.
LSFIT produces a reliable calibration curve for gamma ray spectrometry by using the uncertainty value associated with each data point. LSFIT is intended for use where an entire efficiency curve is to be made starting at 30 KeV and continuing to 1836 KeV. It creates calibration curves using up to three least squares polynomial fits to produce the best curve for photon energies above  120 KeV and a spline function to combine these fitted points with a  best fit for points below 120 KeV.

4. METHOD OF SOLUTION

The quality of fit is tested by comparing the measured y-value to the y-value calculated from the fitted curve. The fractional difference between these two values is printed for the evaluation of the quality of the fit.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   2000 data points calibration curve output (LSFIT)
     30 input data points
      3 least squares polynomial fits (LSFIT)
The least squares polynomial fit requires that the number of data points used exceed the degree of fit by at least two.

6. TYPICAL RUNNING TIME:

7. UNUSUAL FEATURES OF THE PROGRAM

CURVE and LSFIT can operate in the executive mode, which is faster than BASIC and requires less memory.

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES:

- Dale G. Olson:
  Obtaining the Best Efficiency Curve by Curve Fitting Routines
- C. Yuelys-Miskis:
  CURVE,LSFIT Tape Description and Implementation Information
  NESC Note 88-101 (July 29, 1988).

11. MACHINE REQUIREMENTS:

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  VMS 4.6.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS: , Compilation must be done with the GFloat qualifier.

15. NAME AND ESTABLISHMENT OF AUTHORS

          D.G. Olson
          Radiological & Environmental Sciences Laboratory
          Ihado Operations Office

File name	File description	Records
NESC9533_01.001	Information file	114
NESC9533_01.002	CURVE.BAS CURVE source (Turbo Basic)	627
NESC9533_01.003	CURVEVAX.BAS CURVE source (VAX Basic)	614
NESC9533_01.004	LSFIT.BAS LSFIT source (Turbo Basic)	536
NESC9533_01.005	LSFITVAX.BAS LSFIT source (VAX Basic)	522
NESC9533_01.006	CURVE.EXE CURVE executable file	0
NESC9533_01.007	LSFIT.EXE LSFIT executable file	0
NESC9533_01.008	XDATA.FIT Sample input	29
NESC9533_01.009	YDATA.FIT Sample input	29
NESC9533_01.010	ZDATA.FIT Sample input	29
NESC9533_01.011	CURVE.OUT CURVE sample output	75
NESC9533_01.012	LSFIT.OUT LSFIT sample output	133
NESC9533_01.013	DOS file-names	12