Mercurial > hg > ltpda
comparison m-toolbox/classes/+utils/@math/crank.m @ 0:f0afece42f48
Import.
| author | Daniele Nicolodi <nicolodi@science.unitn.it> |
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| date | Wed, 23 Nov 2011 19:22:13 +0100 |
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| -1:000000000000 | 0:f0afece42f48 |
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| 1 % CRANK calculate ranks for Spearman correlation | |
| 2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 3 % Given the data series w | |
| 4 % Calculate: | |
| 5 % rw: the ranks (ties are treated by midranking) | |
| 6 % s: the sum(fk^3 - fk), where fk are the number of kth group of ties | |
| 7 % | |
| 8 % References: | |
| 9 % [1] W. H. Press, S. A. Teukolsky, W. T. Vetterling, B. P. Flannery, | |
| 10 % Numerical Recipes 3rd Edition: The Art of Scientific Computing, | |
| 11 % Cambridge University Press; 3 edition (September 10, 2007) | |
| 12 % | |
| 13 % | |
| 14 % L Ferraioli 06-12-2010 | |
| 15 % | |
| 16 % $Id: crank.m,v 1.1 2011/03/07 10:46:53 luigi Exp $ | |
| 17 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
| 18 function [rw,s] = crank(w) | |
| 19 | |
| 20 [sw,idx] = sort(w); | |
| 21 | |
| 22 n = numel(sw); | |
| 23 s = 0; | |
| 24 jj = 2; | |
| 25 | |
| 26 while jj < n+1 | |
| 27 if sw(jj) ~= sw(jj-1); | |
| 28 sw(jj-1) = jj-1; | |
| 29 jj = jj+1; | |
| 30 else | |
| 31 jt = jj+1; | |
| 32 while jt<=n+1 && sw(jt-1)==sw(jj-1) | |
| 33 jt = jt + 1; | |
| 34 end | |
| 35 rnk = 0.5*(jj+jt-3); | |
| 36 for ji=jj:jt-1 | |
| 37 sw(ji-1)=rnk; | |
| 38 end | |
| 39 t = jt-jj; | |
| 40 s = s + (t*t*t-t); | |
| 41 jj = jt; | |
| 42 end | |
| 43 end | |
| 44 | |
| 45 if jj==n+1 | |
| 46 sw(n)=n+1; | |
| 47 end | |
| 48 | |
| 49 rw = zeros(size(sw)); | |
| 50 for ii=1:numel(sw) | |
| 51 rw(idx(ii)) = sw(ii); | |
| 52 end | |
| 53 | |
| 54 end |