WGAMSTAT Mean and variance for the Gamma distribution. CALL: [m,v] = wgamstat(a,b) m, v = the mean and variance, respectively a = parameter, a>0 b = parameter, b>0 (default b=1) Mean (m) and variance (v) for the Gamma distribution is m=ab and v=ab^2; Example: [m,v] = wgamstat(5,2)
Check if all input arguments are either scalar or of common size. | |
Display message and abort function. | |
Not-a-Number. |
Joint 2D CDF computed as int F(X1 | |
Mean and variance for the DIST2D distribution | |
Mean and variance for the MDIST2D distribution. |
001 function [m,v]= wgamstat(a,b); 002 %WGAMSTAT Mean and variance for the Gamma distribution. 003 % 004 % CALL: [m,v] = wgamstat(a,b) 005 % 006 % m, v = the mean and variance, respectively 007 % a = parameter, a>0 008 % b = parameter, b>0 (default b=1) 009 % 010 % Mean (m) and variance (v) for the Gamma distribution is 011 % 012 % m=ab and v=ab^2; 013 % 014 % Example: 015 % [m,v] = wgamstat(5,2) 016 017 % Reference: Johnson, Kotz and Balakrishnan (1994) 018 % "Continuous Univariate Distributions, vol. 1", p. 494 ff 019 % Wiley 020 021 % Tested on; Matlab 5.3 022 % History: 023 % revised pab Dec2003 024 % fixed a bug: k1 -> k3 025 % revised pab 24.10.2000 026 % - added comnsize, nargchk 027 % added ms 26.06.2000 028 % added b parameter ms 23.08.2000 029 030 error(nargchk(1,2,nargin)) 031 if nargin<2, b=1;end 032 [errorcode a b] = comnsize(a,b); 033 if errorcode > 0 034 error('a and b must be of common size or scalar.'); 035 end 036 037 % Initialize m and v to zero. 038 m = zeros(size(a)); 039 v=m; 040 041 k=find(a > 0 & b>0); 042 if any(k), 043 m(k) = a(k).*b(k); 044 v(k) = m(k).*b(k); 045 end 046 047 k3 = find(a<=0 | b<=0 ); 048 if any(k3) 049 tmp = NaN; 050 m(k3) = tmp(ones(size(k3))); 051 v(k3)=m(k3); 052 end 053 054 055 056
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