Mercurial > hg > ishara
annotate general/numerical/pdev.m @ 35:f1ce7876346a
Updated docs.
author | samer |
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date | Mon, 21 Jan 2013 11:01:45 +0000 |
parents | 8476b3d9d295 |
children |
rev | line source |
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samer@4 | 1 function N=pdev(p,A,D) |
samer@4 | 2 % pdev - p-deviation, generalisation of stddev for exponents other than 2 |
samer@4 | 3 % |
samer@4 | 4 % pdev :: nonneg, [[D1]], I:natural -> [[D2]]. |
samer@4 | 5 % pdev :: nonneg, [[N D]] -> [[ 1 D]]. |
samer@4 | 6 % |
samer@4 | 7 % where D2 = set(D1,I,1), ie the Ith dimension is |
samer@4 | 8 % collapsed. I defaults to 1. The p-deviation is defined as |
samer@4 | 9 % pdev(p,x,i) = mean(abs(x).^p,i).^(1/p) |
samer@4 | 10 % |
samer@4 | 11 % See also pnorm. |
samer@4 | 12 |
samer@4 | 13 if nargin<2, D=1; end; |
samer@4 | 14 |
samer@4 | 15 if p==2 |
samer@4 | 16 N=sqrt(mean(abs(A).^2,D)); |
samer@4 | 17 else |
samer@21 | 18 N=real(mean(abs(A).^p,D).^(1/p)); |
samer@4 | 19 end |
samer@4 | 20 |
samer@4 | 21 |