error occurs in the present code

function main

clc

clear all

x=3;

options=optimset('Display','iter');

x1=fsolve(@solver,x,options);

function F=solver(x)

options=odeset('RelTol',le-8,'AbsTol',[le-8, le-8, le-8]);

[t,u]=ode45(@equation,[0,20],[4 -1 x],options);

s=length(t);

F=u(s,2);

figure(1)

plot(t,u(:,2))

hold on

end

end

function dy=equation(t,y)

dy=zeros(3,1);

dy(1)=y(2);

dy(2)=y(3);

dy(3)=y(2)^2-y(1)*y(3);

end

After running the above code following error occurs:

Not enough input arguments.

Error in fsolve (line 230)

fuser = feval(funfcn{3},x,varargin{:});

Error in (line 10)

x1=fsolve(@solver,x,options);

Caused by:

Failure in initial objective function evaluation. FSOLVE cannot continue.

Answer 1

[Star Strider]

You have a typographical error in your odeset call. You typed ‘l’ (lower-case ‘L’) instead of the number 1.

Use this instead:

options=odeset('RelTol',1e-8,'AbsTol',1e-8);

and your code runs without error.

When I ran it,, the result was:

x1 =
     3.732

[MINATI]

Thanks for your quick and right response.

I need a single curve

But it gives multiple graphs(13) and it is taking so much time if I change

[t,u]=ode45(@equation,[0,20],[1 -1 x],options); % bold from 4 to 1(50 curves)

any modification needed in the program?

[Star Strider]

I am not certain what you want. If you want to plot a single curve (with the optimised value for the third initial condition), just plot the last one.

Try this:

x=3;  
options=optimset('Display','iter');
x1=fsolve(@solver,x,options)
function F=solver(x)
options=odeset('RelTol',1e-8,'AbsTol',1e-8);
[t,u]=ode45(@equation,[0,20],[4 -1 x],options);
s=length(t);
F=u(s,2);
% figure(1)
%     plot(t,u(:,2))
%     hold on
% end
% end
function dy=equation(t,y)
dy=zeros(3,1);
dy(1)=y(2);
dy(2)=y(3);
dy(3)=y(2)^2-y(1)*y(3);
end
end

function dy=equation(t,y)
dy=zeros(3,1);
dy(1)=y(2);
dy(2)=y(3);
dy(3)=y(2)^2-y(1)*y(3);
end

[t,u]=ode45(@equation,[0,20],[4 -1 x1],options);
figure(1)
plot(t,u(:,2))

Esperiment to get the result you want.

[MINATI]

Dear STAR

many many thanks.

It worked now.

Thanks

[Star Strider]

As always, my pleasure.

[MINATI]

[t,u]=ode45(@equation,[0,20],[4 -1 x1],options);

what is the significance of 4 in [4 -1 x1]

[Star Strider]

It is one of the initial conditions for your ‘equation’ function differential equation system.

[Rik]

Related question in this new thread.