disser1.pdf (2006 KB) - Ernst-Moritz-Arndt-Universität Greifswald

C. MATLAB-Programme
% plot(t,y(:,1:3));
size(y);
for j=1:size(y,1)-1
l(w(1)/z+1-j,2:4)=y(1+j,1:3);
l(w(1)/z+1-j,1)=y(1+j,4);
end;
plot(l(:,1),l(:,2:4));
l(1,:);
C.3. Programm 3. Berechnung bei quadratischen
Modellen (optimaler Fang).
clear all;
options = [];
sol = bvpinit(linspace(0,20,50),[1 0 0]);
sol = bvp4c(@odesys,@bc,sol,options);
x = [sol.x];
y1 = [sol.y(1,:)]; y2 = [sol.y(2,:)]; y3 = [sol.y(3,:)];
y=[y1;y2;y3];
for i=1:size(y,2)
y4(i)=(0.42375*y(1,i)-y(1,i)*0.000375* ...
exp(0.06*y(3,i))*y(2,i))/(2*0.00125);
end; y,
%plot(x,y1(1,:))
plot(y3,y4)
title(’Randwertproblem’)
xlabel(’t’)
ylabel(’u(t)’)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function res = bc(ya,yb)
%Boundary conditions
res = [ ya(1)-0.25
yb(2)
ya(3)];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function dydx = odesys(x,y,n)
% ODE function
dydx = [ 0.4*y(1)*(1-y(1))-0.000375* ...
((0.42375*y(1)^2-y(2)*0.000375 ...
*y(1)^2*exp(0.06*y(3)))/(2*0.00125))
((-0.42375^2*y(1)*exp(-0.06*y(3))+ ...
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