WWEIBPDF Weibull probability density function CALL: f = wweibpdf(x,a,c); f = density function evaluated at x a, c = parameters The Weibull distribution is defined by its cdf F(x;a,c) = 1 - exp(-(x/a)^c), x>=0, a,b>0 Some references refer to the Weibull distribution with a single parameter, this corresponds to WWEIBPDF with a = 1. Example: x = linspace(0,6,200); p1 = wweibpdf(x,1,1); p2 = wweibpdf(x,2,2); p3 = wweibpdf(x,2,5); plot(x,p1,x,p2,x,p3)
Check if all input arguments are either scalar or of common size. | |
Display message and abort function. | |
Not-a-Number. |
is an internal function to dist2dcdf dist2dprb. | |
Joint 2D PDF computed as f(x1|X2=x2)*f(x2) | |
Joint (Vcf,Hd) PDF for linear waves with a JONSWAP spectrum. | |
Joint (Vcf,Hd) PDF for linear waves with a JONSWAP spectrum. | |
Long Term Wave Climate PDF of significant wave height and wave period | |
Joint 2D PDF due to Plackett given as f{x1}*f{x2}*G(x1,x2;Psi). | |
Myrhaug and Kjeldsen (1987) joint (Scf,Hd) PDF. | |
Joint (Scf,Hd) PDF for linear waves with Ochi-Hubble spectra. | |
Joint (Scf,Hd) PDF linear waves in space with Ochi-Hubble spectra. | |
Joint (Vcf,Hd) PDF for lineare waves with Ochi-Hubble spectra. | |
Joint (Vcf,Hd) PDF for linear waves with Torsethaugen spectra. |
001 function f = wweibpdf(x,a,c) 002 %WWEIBPDF Weibull probability density function 003 % 004 % CALL: f = wweibpdf(x,a,c); 005 % 006 % f = density function evaluated at x 007 % a, c = parameters 008 % 009 % The Weibull distribution is defined by its cdf 010 % 011 % F(x;a,c) = 1 - exp(-(x/a)^c), x>=0, a,b>0 012 % 013 % Some references refer to the Weibull distribution with 014 % a single parameter, this corresponds to WWEIBPDF with a = 1. 015 % 016 % Example: 017 % x = linspace(0,6,200); 018 % p1 = wweibpdf(x,1,1); p2 = wweibpdf(x,2,2); p3 = wweibpdf(x,2,5); 019 % plot(x,p1,x,p2,x,p3) 020 021 % Reference: Cohen & Whittle, (1988) "Parameter Estimation in Reliability 022 % and Life Span Models", p. 25 ff, Marcel Dekker. 023 024 025 % Tested on; Matlab 5.3 026 % History: 027 % revised pab 24.10.2000 028 % - added comnsize, nargchk 029 % rewritten ms 15.06.2000 030 031 032 error(nargchk(3,3,nargin)) 033 034 [errorcode, x, a, c] = comnsize (x,a, c); 035 if (errorcode > 0) 036 error ('x, a and c must be of common size or scalar'); 037 end 038 039 f=zeros(size(x)); 040 041 ok = ((c > 0) & (a > 0)); 042 043 k = find (x>=0&ok); 044 if any (k) 045 f(k)=(x(k)./a(k)).^(c(k)-1).*c(k)./a(k).*exp(-(x(k)./a(k)).^c(k)); 046 end 047 048 k1 = find (~ok); 049 if any (k1) 050 tmp=NaN; 051 f(k1) = tmp(ones(size(k1))); 052 end 053 054 055 056 057 058 059
Comments or corrections to the WAFO group