tbgitoo.tools

Class FitParabola

java.lang.Object

tbgitoo.tools.FitParabola

public class FitParabola
extends java.lang.Object

Fit a parabolic profile to unit-spaced values

Author:

thomasbraschler

Constructor Summary

Constructors

Constructor and Description
FitParabola()

Method Summary

Modifier and Type	Method and Description
static double[]	fitParabola(double[] vals) Fits a parabola (a + bx + cx^2) to series of values (vals).
static double[]	fitParabolaFixedExtremum(double[] vals, int xm) Fits a parabola (a + bx + cx^2) to series of values (vals), but under the restriction that the appex has to occur at the x=xm For the peak fitting purpose intended, xm should be in the interval 0 ..
static double[]	fitParabolaFixedExtremum(double[] vals, int xm, boolean force_xm_in_array_domain) Fits a parabola (a + bx + cx^2) to series of values (vals), but under the restriction that the appex has to occur at the x=xm

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FitParabola

public FitParabola()

Method Detail

fitParabola

public static double[] fitParabola(double[] vals)

Fits a parabola (a + bx + cx^2) to series of values (vals). The values are regularly spaced, and the x coordinate is assumed to be 0,1,2,3... that is as in standard array indexing in Java

Parameters:

vals - Array of values defining the parabola to be fitted

Returns:

array of three values, representing the coefficients a, b, c for the parabolic fit. Order (offset, linear, squared)

fitParabolaFixedExtremum

public static double[] fitParabolaFixedExtremum(double[] vals,
                                                int xm)

Fits a parabola (a + bx + cx^2) to series of values (vals), but under the restriction that the appex has to occur at the x=xm For the peak fitting purpose intended, xm should be in the interval 0 .. length(vals)-1, and this condition is reinforced

Parameters:

vals - Array of values defining the parabola to be fitted

xm - Force location of the apex of the parabola.

Returns:

array of three values, representing the coefficients a, b, c for the parabolic fit. Order (offset, linear, squared)

fitParabolaFixedExtremum

public static double[] fitParabolaFixedExtremum(double[] vals,
                                                int xm,
                                                boolean force_xm_in_array_domain)

Fits a parabola (a + bx + cx^2) to series of values (vals), but under the restriction that the appex has to occur at the x=xm

Parameters:

vals - Array of values defining the parabola to be fitted

xm - Force location of the apex of the parabola.

force_xm_in_array_domain - Force xm to be in the interval 0 .. length(vals)-1 ?

Returns:

array of three values, representing the coefficients a, b, c for the parabolic fit. Order (offset, linear, squared)