pro prob_ks, D, N_eff, probks;+; NAME:;       PROB_KS; PURPOSE:;       Return the significance of the Kolmogoroff-Smirnov statistic; EXPLANATION:;       Returns the significance level of an observed value of the ;       Kolmogorov-Smirnov statistic D for an effective number of data points;       N_eff.   Called by KSONE and KSTWO;; CALLING SEQUENCE:;       prob_ks, D, N_eff, probks;; INPUT PARAMATERS:;       D -  Kolmogorov statistic, floating scalar, always non-negative;       N_eff - Effective number of data points, scalar.   For a 2 sided test ;               this is given by (N1*N2)/(N1+N2) where N1 and N2 are the number ;               of points in each data set.;; OUTPUT PARAMETERS:;       probks - floating scalar between 0 and 1 giving the significance level of;               the K-S statistic.   Small values of PROB suggest that the ;               distribution being tested are not the same;; REVISION HISTORY:;       Written     W. Landsman                August, 1992;       Corrected typo (termbv for termbf)    H. Ebeling/W.Landsman  March 1996;       Probably did not affect numeric result, but iteration went longer;       than necessary;       Converted to IDL V5.0   W. Landsman   September 1997;- On_error,2 if N_params() LT 3 then begin     print,'Syntax - prob_ks, D, N_eff, prob'     print,'  D - Komolgorov-Smirnov statistic, input'     print,'  N_eff - effective number of data points, input'     print,'  prob - Significance level of D, output'     return endif eps1 = 0.001    ;Stop if current term less than EPS1 times previous term eps2 = 1.e-8    ;Stop if current term changes output by factor less than EPS2 en = sqrt( N_eff ) lambda = (en + 0.12 + 0.11/en)*D a2 = -2.*lambda^2 probks = 0. termbf = 0. sign = 1. for j = 1,100 do begin      term = sign*2*exp(a2*j^2)     probks = probks + term     if ( abs(term) LE eps1*termbf ) or $         ( abs(term) LE eps2*probks ) then return     sign = -sign                  ;Series alternates in sign     termbf = abs(term) endfor probks = 1.          ;Sum did not converge after 100 iterations return end