Function with different parameters

Hi everyone,

I am trying to vary the parameter e =[0.0001,0.0005,0.001,0.005,0.01] in my function and want to plot it in one figure. how can I do it?

Thank you!!

Hier is my code:

% Main program
s0=1;
c0=0;
t=linspace(0,10,100);
x0=[s0 c0];

[t,x]=ode45(@(t,x) num_lsg1(t,x), t, x0); 
plot(t,x(:,1),'-o',t, x(:,2),'-x')
xlabel('time [s]');
ylabel('Substrat, Complex');
legend('Substrat','Complex')

%%Function definition
function dx=num_lsg1(t,x) 
% Parameters
kme=0.625; 
e=0.001; 
kmm=1;
dx=zeros(2,1);
dx(1)=kme*x(2)-x(1)*(1-x(2));
dx(2) = (x(1)*(1-x(2))-kmm*x(2))/e;
end

[Stephen23]

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

Answer 1

[madhan ravi]

Parameterize your function

s0=1;
c0=0;
t=linspace(0,10,100);
x0=[s0 c0];
for e =[0.0001,0.0005,0.001,0.005,0.01]
[t,x]=ode45(@(t,x) num_lsg1(t,x,e), t, x0);  % function call
figure
plot(t,x(:,1),'-o',t, x(:,2),'-x')
xlabel('time [s]');
ylabel('Substrat, Complex');
legend('Substrat','Complex')
end

%%Function definition
function dx=num_lsg1(t,x,e) 
% Parameters
kme=0.625; 
kmm=1;
dx=zeros(2,1);
dx(1)=kme*x(2)-x(1)*(1-x(2));
dx(2) = (x(1)*(1-x(2))-kmm*x(2))/e;
end

Note: If you dont want separate figures you can remove figure and put hold on after the plot command because if you plot them in the same figure all the plots look the same because e variation is so small,.

[Tatjana Henning]

Hey, thank you so much for the fast answer (and the note!) again! It works.

I plotted it in the same figure. You can see the difference, wenn you plot between 0 and 0.01. :)

Now I tried to put 2 different dif.eq. and the difference between them in the same plot. Is my code ok? It works, but I am not sure, if it shows, what it should.

% 1
% Main program
s1=1;
t=linspace(0,10,100);
x0=[s1];

% 2
% Main program
s2=1;
c0=0;
t=linspace(0,10,100);
x00=[s2 c0];

[t,x1]=ode45(@(t,x1) num_lsg1(t,x1), t, x0); 
[t,x2]=ode45(@(t,x2) num_lsg2(t,x2), t, x00); 
%plot(t,x1(:,1),'-o ')
%hold on;
%plot(t,x2(:,1),'-o',t, x2(:,2),'-x')
%hold on;
plot(t,x1(:,1)-x2(:,1),'-* ')
xlabel('time [s]');
ylabel('Substrat');
legend('1','2','difference')

%%function 1
function dx1=num_lsg1(t,x1) 
% parameters
kme=0.625; 
kmm=1;
k=kmm-kme;
dx1=zeros(1,1);
dx1(1)=-(k*x1(1))/(kmm+x1(1));
end

%%function 2
function dx2=num_lsg2(t,x2) 
% parameters
kme=0.625; 
e=0.001;
kmm=1;
dx2=zeros(2,1);
dx2(1)=kme*x2(2)-x2(1)*(1-x2(2));
dx2(2) = (x2(1)*(1-x2(2))-kmm*x2(2))/e;
end

[madhan ravi]

Anytime :) ,

plot(t,x1(:,1),'-ok',t,x2(:,1),'-* ') % correct syntax

By the way I don't see the difference in the same plot it looks like they lie on each other anyway it's your wish.

[University Glasgow]

Hi please, how can plot for two different values of the varing parameters on the same figure. For instance, e= 0.0001 and e= 0.0005 on the same figure?