www.pudn.com > FitFunc.zip > plot_maxwell.m

function plot_maxwell( x,params,hAx,plot_num,fontsize ) 
% plot the maxwell distribution with parameter "a" 
%  
% the distribution is given by: 
%
%        p(r) = sqrt(2/pi)*(a^(-3/2))*(r^2)*exp(-(r^2)/(2*a)) 
% 
% format:   plot_maxwell( x,params,hAx,plot_num,fontsize ) 
% 
% input:    x         - X axis, for the plot
%           params    - the distribution parameter, RMS error and VAR or CRB
%           hAx       - where to plot the distribution curve
%           plot_num  - since the curve is added with a text to the axes, 
%                       this parameter specifies where the text should be displayed
%                       and what color to choose for the curve 
%           fontsize  - size of the font of the text, default 9 
%
% 
% example:  plot_maxwell( x,fit_ML_maxwell(data),hAx,3 ) 
% 
 
% init graphic parameters 
switch plot_num 
case 1, cl = [1 0 0]; 
case 2, cl = [0 1 0]; 
case 3, cl = [1 0 1]; 
case 4, cl = [0 1 1]; 
case 5, cl = [0.5 0.5 0]; 
end 
if ~exist('fontsize') 
    fontsize = 9; 
end 
p       = plot_num*0.15 + 0.3; 
ylimit  = ylim(hAx); 
xlimit  = xlim(hAx); 
fnc_txt = '\surd\it{2/\pi}  \bf{\cdot a}^{-3/2}\bf{x}^2\bf{e}^{-x^2/2a}\rm'; 
if isfield( params,'VAR' ) 
    txt     = sprintf( '\\fontsize{%d}\\bfMaxwell PDF\\rm with %s:  %s\na               = %g\nVAR(a)      = %1.3g\nRMS err(a) = %1.3g\n',... 
        fontsize,params.type,fnc_txt,params.a,params.VAR,params.RMS ); 
else 
    txt     = sprintf( '\\fontsize{%d}\\bfMaxwell PDF \\rmwith %s:  %s\na               = %g\nCRB(a)      = %1.3g\nRMS err(a) = %1.3g\n',... 
        fontsize,params.type,fnc_txt,params.a,params.CRB,params.RMS );  
end 
 
% calculate distribution 
a       = params.a; 
x2      = x.^2; 
y       = sqrt(2/pi)*x2.*a^(-1.5).*exp(-x2/(2*a)); 
 
% plot and write the text 
line( 'parent',hAx,'xdata',x,'ydata',y,'linewidth',2,'color',cl ); 
hTxt    = text( 1.2*mean(x),ylimit(2)*p,txt,'parent',hAx ); 
ext     = get( hTxt,'Extent' ); 
line( ext(1) - xlimit/15 ,(ext(2)+ext(4)/2)*[1 1],'linewidth',3,'color',cl ); 
% ext(3)  = ext(3)+xlimit(2)/15; 
% rectangle( 'position',ext );