Index in position 1 is invalid. Array indices must be positive integers or logical values.

I've attached my code below. I keep getting the issue of incorrect indexing but I'm not sure why this is as I have defined my for loop starting at 1. If someone could take a quick look and help me that would be great. I feel like I'm just overlooking something. The error occurs in line 36

[jonas]

Cannot pinpoint the issue, but avoid using sum as a variable name, it's a built in function. Seems you have some custom functions necessary to run the script.

[PenguinForce]

Thanks for that heads up. The fact sum is a function name definitely slipped my mind

[Rik]

The same goes for using i as a loop counter. If by some strange reason it gets interpreted as the imaginary unit, you'll get these kinds of errors.

[PenguinForce]

Neither of these suggestions is fixing the code though to make it work

Answer 1

[jonas]

Here is something fishy.

sigma = func2(t,x,sigma_x,func1(kc,t))
...
function sigma = func2(t,M,sigma_M,func1)

If you want to pass the output of func2 as an input to func1 that's ok, but do not name the output func1. This confusion causes func1 to be interpreted as a variable, which is why you get this error. You can pass the function as an argument like you do, but you need to name the variable used in func2 something other than func1.

What you do is similar to writing:

func1 = func1(arg1,arg2)

func1 is now a variable, so the next time you call it it will be interpreted as such.

[jonas]

Well no wonder, since you changed both the variable name and the function call to func11... don't use obfuscating variable names if you want to write clear easy-to-debug code. If you still do not see it..

total = total + ((func11(temp1,t(n)) - func11(temp2,t(n)))/2)^2;
                       ↑                    ↑

remove these 1's, and you will be able to run the code. You are trying to use the function here right, and not a variable?

I don't even know why you pass the func11 variable to the func2 function, it seems you are not even using it.

[PenguinForce]

Ah! Thank you so much! You are absolutely right. I'm not really using them. Thank you again for your time!! :)