WEXPPDF Exponential probability density function CALL: f = wexppdf(x,m); f = density function evaluated at x m = mean The Exponential distribution is defined by its pdf f(x)=exp(-x/m)/m, x>=0, m>0. Example: x = linspace(0,6,200); p1 = wexppdf(x,1); p2 = wexppdf(x,2); plot(x,p1,x,p2)
Check if all input arguments are either scalar or of common size. | |
Display message and abort function. | |
Not-a-Number. |
001 function f = wexppdf(x,m); 002 %WEXPPDF Exponential probability density function 003 % 004 % CALL: f = wexppdf(x,m); 005 % 006 % f = density function evaluated at x 007 % m = mean 008 % 009 % The Exponential distribution is defined by its pdf 010 % 011 % f(x)=exp(-x/m)/m, x>=0, m>0. 012 % 013 % Example: 014 % x = linspace(0,6,200); 015 % p1 = wexppdf(x,1); p2 = wexppdf(x,2); 016 % plot(x,p1,x,p2) 017 018 % Reference: Johnson, Kotz and Balakrishnan (1994) 019 % "Continuous Univariate Distributions, vol. 1", p. 494 ff 020 % Wiley 021 022 % Tested on; Matlab 5.3 023 % History: 024 % Revised pab Dec2003 025 % fixed abug k1->k3 026 % revised pab 24.10.2000 027 % - added comnsize, nargchk 028 % added ms 15.06.2000 029 030 error(nargchk(2,2,nargin)) 031 032 [errorcode x m] = comnsize(x,m); 033 if errorcode > 0 034 error('x and m must be of common size or scalar.'); 035 end 036 037 % Initialize f to zero. 038 f = zeros(size(x)); 039 040 k=find(x >= 0 & m>0); 041 if any(k), 042 f(k)=exp(-x(k)./m(k))./m(k); 043 end 044 045 k3 = find(m<=0); 046 if any(k3) 047 tmp = NaN; 048 f(k3) = tmp(ones(size(k3))); 049 end 050 051 052
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