1 /*
2 * SlopeInterceptLineFit.java
3 *
4 * Created on March 27, 2006, 3:19 PM
5 *
6 * $Id: SlopeInterceptLineFit.java,v 1.1 2006/03/28 04:51:03 ngraf Exp $
7 */
8
9 package org.lcsim.fit.line;
10 /**
11 * The result of a fit to a 2-D line in slope-intercept form y=a+bx .
12 * @author Norman Graf
13 */
14 public class SlopeInterceptLineFit
15 {
16 private double _slope;
17 private double _intercept;
18 private double _sigA;
19 private double _sigB;
20 private double _sigAB;
21 private double _chisq;
22 private int _ndf;
23 /**
24 * Creates a new instance of SlopeInterceptLineFit
25 *
26 *
27 * @param slope The slope of the line.
28 * @param intercept The intercept of the line.
29 * @param slopeUncertainty The uncertainty on the slope
30 * @param interceptUncertainty The uncertainty on the intercept
31 * @param sigAB The covariance term.
32 * @param chisq The chi-squared of the fit
33 * @param ndf The number of degrees of freedom for the fit
34 */
35 public SlopeInterceptLineFit(double slope, double intercept, double slopeUncertainty, double interceptUncertainty, double sigAB, double chisq, int ndf)
36 {
37 _slope = slope;
38 _intercept = intercept;
39 _sigA = interceptUncertainty;
40 _sigB = slopeUncertainty;
41 _sigAB = sigAB;
42 _chisq = chisq;
43 _ndf = ndf;
44 }
45
46 /**
47 *
48 * @return The fit slope of the line.
49 */
50 public double slope()
51 {
52 return _slope;
53 }
54
55 /**
56 *
57 * @return The uncertainty on the fit slope of the line.
58 */
59 public double slopeUncertainty()
60 {
61 return _sigB;
62 }
63
64 /**
65 *
66 * @return The fit intercept of the line.
67 */
68 public double intercept()
69 {
70 return _intercept;
71 }
72
73 /**
74 *
75 * @return The uncertainty on the fit intercept of the line.
76 */
77 public double interceptUncertainty()
78 {
79 return _sigA;
80 }
81
82 /**
83 *
84 * @return The covariance of the slope-intercept uncertainties.
85 */
86 public double covariance()
87 {
88 return _sigAB;
89 }
90
91 /**
92 *
93 * @return The chi-squared of the fit.
94 */
95 public double chisquared()
96 {
97 return _chisq;
98 }
99
100 /**
101 *
102 * @return The number of degrees of freedom in the fit.
103 */
104 public int ndf()
105 {
106 return _ndf;
107 }
108
109 public String toString()
110 {
111 StringBuffer sb = new StringBuffer("SlopeInterceptLineFit: \n");
112 sb.append("slope= "+_slope+" +/- "+_sigB+" intercept= "+_intercept+" +/- "+_sigA+" cov: "+_sigAB+ "\n");
113 sb.append("chi-squared for "+_ndf+" degrees of freedom is "+_chisq);
114 return sb.toString();
115 }
116 }