WLOGNSTAT Mean and variance for the Lognormal distribution. CALL: [m,v] = wlognstat(m0,v0) m, v = the mean and variance, respectively m0, v0 = parameters of the Lognormal distribution. Mean (m) and variance (v) for the Lognormal distribution is m=exp(m0+v0/2) and v=exp(2*m0+v0)*(exp(v0)-1); Example: [m,v] = wlognstat(0,1)
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]= wlognstat(m0,v0); 002 %WLOGNSTAT Mean and variance for the Lognormal distribution. 003 % 004 % CALL: [m,v] = wlognstat(m0,v0) 005 % 006 % m, v = the mean and variance, respectively 007 % m0, v0 = parameters of the Lognormal distribution. 008 % 009 % Mean (m) and variance (v) for the Lognormal distribution is 010 % 011 % m=exp(m0+v0/2) and v=exp(2*m0+v0)*(exp(v0)-1); 012 % 013 % Example: 014 % [m,v] = wlognstat(0,1) 015 016 % Reference: Cohen & Whittle, (1988) "Parameter Estimation in Reliability 017 % and Life Span Models", p. 59 ff, Marcel Dekker. 018 019 020 021 % Tested on; Matlab 5.3 022 % History: 023 % revised pab 24.10.2000 024 % - added comnsize, nargchk 025 % - added default values 026 % added ms 10.08.2000 027 028 error(nargchk(0,2,nargin)) 029 if nargin<1|isempty(m0), m0=0; end 030 if nargin<2|isempty(v0), v0=1; end 031 032 [errorcode, m0, v0] = comnsize (m0, v0); 033 if (errorcode > 0) 034 error ('m and v must be of common size or scalar'); 035 end 036 037 m = zeros(size(m0)); 038 v = m; 039 k = find(v0>=0); 040 if any(k), 041 m(k) = exp(m0(k)+v0(k)/2); 042 v(k) = exp(2*m0(k)+v0(k)).*(exp(v0(k))-1); 043 end 044 k1 = find(v0<0); 045 if any(k1), 046 tmp=NaN; 047 m(k1) = tmp(ones(size(k1))); 048 v(k1) = m(k1); 049 end 050 051 052
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