I am getting Error using deval

function yd = hyperchaos(t,y) %%%% selecting some cases for publication

global aa bb dd aa =3.55;

dd = 0;

mm=1;

n1 =1-aa*(y(2))*y(3);

n2 =1*y(3)*abs(y(3))-(y(3));

n3 =1*(mm*(abs(y(1))-dd))-bb*y(3);

n4 = 0 ;

A=[ 0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0];

B=[n1

n2

n3

n4];

yd=A*y+B;

clear

format long

global aa bb dd cc kk ee rr mm mm2 nn

dt=5*10^(-3);

tspan=(0:dt:500);

for i = 1:1:1

i

bb = -5+ (i-1)*0.025

dd = 0;

Y0=[0 5 0 0];

sol = ode45(@hyperchaos,[tspan(1) tspan(end)],Y0);

ss = deval(sol,tspan)';

s = ss(1500:end,:);

backColor = [0.5 0.5 0.5];

plot(s(1:end,1),s(1:end,2),'g'); xlabel('X');ylabel('Y')

drawnow

end

error:

>> main

i =

1

bb =

-5

Warning: Failure at t=2.738123e+00. Unable to meet integration tolerances without reducing the step size below

the smallest value allowed (7.105427e-15) at time t.

> In ode45 (line 351)

In main (line 23)

Error using deval (line 137)

Attempting to evaluate the solution outside the interval [0.000000e+00, 2.738123e+00] where it is defined.

Error in main (line 24)

ss = deval(sol,tspan)';

>>

Answer 1

[Torsten]

Your integration could not be continued beyond t = 2.738123.

So you try to evaluate the solution in a region where you have no data available.