Error Array indices must be positive integers or logical values. when doing euler's method.

I am tyring to do euler's method with the logistic function dx/dt= xr(1-x/L). Where r=0.65 and L=5.4, intial value is x(0)=6 and t (0,30), and h=0.5. This is my code as of now( I have tried a bunch of different codes giving me the same error).

h=1/2;
N=60; 
x(0)=6;
r= 0.65;
L=5.4;
dx= @(x)(r*x)*(1-x/L)
for n=0:N
t(n+1)=t(n)+h;
x(n+1)=x(n)+h*dx(x(n));
end 
%I also tried it with
h=1/2;
N=60; 
x(0)=6;
r= 0.65;
L=5.4;
dx= @(t,x)(r*x)*(1-x/L)
for n=0:N
t(n+1)=t(n)+h;
x(n+1)=x(n)+h*dx(t(n), x(n));
end

[Stephen23]

MATLAB indexing starts at one, not zero.

Answer 1

[Shanmukha Voggu]

Hi Kaitlyn,

The error you are facing is due to accessing the zeroth index of the vector

t=[14 6 3] % creating a simple vector

t = 1×3

14 6 3

firstElement=t(1) % first element of the array is accessed by index "1"

firstElement = 14

t(0) %produces error because zeroth index is not available 

Array indices must be positive integers or logical values.

Refer to this for more information