Code for Figure 8.10

main.m


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35% Copyright (C) 2001, James B. Rawlings and John G. Ekerdt
%
% This program is free software; you can redistribute it and/or
% modify it under the terms of the GNU General Public License as
% published by the Free Software Foundation; either version 2, or (at
% your option) any later version.
%
% This program is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
% General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; see the file COPYING.  If not, write to
% the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
% MA 02111-1307, USA.

x=linspace(0,5,200)';
tau=2;
Ds=[0.002 0.01 0.05 0.2];
%Ds=[.005];
for i = 1:length(Ds)
D= Ds(i);
arg = (1-x/tau)./sqrt(x/tau)/sqrt(4*D);
P(:,i) = 0.5*(1-erf(arg));
%  LevP(:,i) = 0.5*(1+erf( ((x/tau)-1)./sqrt(4*D) ));
p(:,i) = 1/(2*tau*sqrt(pi*4*D)) .* exp(-arg.*arg).*(tau./x+1)./sqrt(x/tau);
end
Ptable = [x P];
ptable = [x p];
save -ascii dispersionP.dat Ptable;
if (~ strcmp (getenv ('OMIT_PLOTS'), 'true')) % PLOTTING
plot (Ptable(:,1), Ptable(:,2:5));
% TITLE
end % PLOTTING