/usr/share/gnudatalanguage/astrolib/kuiperone.pro is in gdl-astrolib 2018.02.16+dfsg-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 | pro kuiperone, data, func_name, d, prob, PLOT = plot, WINDOW=window, $
_EXTRA = extra
;+
; NAME:
; KUIPERONE
; PURPOSE:
; Compute the one-sided Kuiper statistic (invariant Kolmogorov-Smirnov)
; EXPLANATION:
; Returns the Kuiper statistic and associated probability
; for an array of data values and a user-supplied cumulative distribution
; function (CDF) of a single variable. Algorithm adapted from KSONE
; in "Numerical Recipes" by Press et al. 2nd edition (1992)
;
; Kuiper's test is especially useful for data defined on a circle or
; to search for periodicity (see Paltani 2004, A&A, 420, 789).
; CALLING SEQUENCE:
; kuiperone, data, func_name, D, prob, [ /PLOT ]
;
; INPUT PARAMETERS:
; data - vector of data values, must contain at least 4 elements for the
; Kuiper statistic to be meaningful
; func_name - scalar string giving the name of the cumulative distribution
; function. The function must be defined to accept the data
; vector as its only input (see example).
;
; OUTPUT PARAMETERS:
; D - floating scalar giving the Kuiper statistic. It
; specifies the sum of positive and negative deviations between the
; cumulative distribution of the data and the supplied function
; prob - floating scalar between 0 and 1 giving the significance level of
; the Kuiper statistic. Small values of PROB show that the
; cumulative distribution function of DATA is significantly
; different from FUNC_NAME.
;
; OPTIONAL INPUT KEYWORD:
; /PLOT - If this keyword is set and non-zero, then KUIPERONE will display a
; plot of the CDF of the data with the supplied function
; superposed. The data values where the Kuiper statistic is
; computed (i.e. at the maximum difference between the data CDF
; and the function) are indicated by vertical dashed lines.
; KUIPERONE accepts the _EXTRA keyword, so that most plot keywords
; (e.g. TITLE, XTITLE, XSTYLE) can also be passed to KUIPERONE.
;
; EXAMPLE:
; Determine if a vector created by the RANDOMN function is really
; consistent with a Gaussian distribution.
; The CDF of a Gaussian is the error function except that a factor
; of 2 is included in the error function. So we must create a special
; function:
;
; function gauss_cdf, x
; return, errorf( x/sqrt(2) )
; end
;
; IDL> data = randomn(seed, 50) ;create data array to be tested
; IDL> kuiperone, data, 'gauss_pdf', D, prob, /PLOT ;Use Kuiper test
;
; A small value of PROB indicates that the cumulative distribution of
; DATA is significantly different from a Gaussian
;
; NOTES:
; Note that the 2nd (1992) edition of Numerical Recipes includes
; a more accurate computation of the K-S significance for small
; values of N.
;
; PROCEDURE CALLS
; procedure PROB_KUIPER - computes significance of Kuiper distribution
;
; REVISION HISTORY:
; Written W. Landsman August, 1992
; Accept _EXTRA keywords W. Landsman September, 1995
; Fixed possible bug in plot display showing position maximum difference
; in histogram M. Fardal/ W. Landsman March, 1997
; Adapted from KSONE J. Ballet July 2003
; Use Coyote graphics W. Landsman Feb 2011
;-
On_error, 2
compile_opt idl2
if ( N_params() LT 3 ) then begin
print,'Syntax - kuiperone, data, func_name, D, [prob ,/PLOT]'
return
endif
N = N_elements( data )
if N LT 3 then message, $
'ERROR - Input data values (first param) must contain at least 3 values'
sortdata = data[ sort( data ) ]
f0 = findgen(N)/ N
fn = ( findgen( N ) +1. ) / N
ff = call_function( func_name, sortdata )
; Maximum distance above the reference
D1 = max( fn-ff, subn )
; Maximum distance below the reference
D2 = max( ff-f0, sub0 )
D = D1 + D2
if keyword_set(plot) || keyword_set(WINDOW) then begin
; Prepare the step function
xx = REBIN(sortdata,2*N,/SAMPLE)
yy = REBIN(f0,2*N,/SAMPLE)
yy = [yy[1:*],1.]
cgplot, xx,yy,_EXTRA = extra, WINDOW=window
cgplots, [sortdata[sub0], sortdata[sub0]], [0,ff[sub0]], linestyle=2, $
WINDOW=window
cgplots, [sortdata[subn], sortdata[subn]], [ff[subn],1], linestyle=2, $
WINDOW=window
; Plot the expected cumulative distribution
n2 = n > 100
x2 = FINDGEN(n2+1)*(!X.CRANGE[1]-!X.CRANGE[0])/n2 + !X.CRANGE[0]
y2 = call_function( func_name, x2 )
cgplot,/over, x2,y2,lines=1,thick=2, WINDOW=window
endif
prob_kuiper, D, N, prob ;Compute significance of Kuiper statistic
return
end
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