Function definitions must appear at end of file

I'm getting this error for this code snippet and I don't know why:

%psum.m

function[sum, steps] = psum(tol)

sum = 1.0;

steps = 1;

while abs(sum-pi^2/6.0) >= tol

      steps = steps +1;

      sum = sum + 1 / steps ^2;

end

end

%project2.m

tols = [0.1 0.05 0.01 0.005 0.001];

for i = 1 : 5

      tols = [0.1 0.05 0.01 0.005 0.001];

      [errors(i), totalSteps(i)] = psum(tols(i));

end

loglog(errors, tols, totalSteps, tols)

Answer 1

[David Fletcher]

As it says, if you are going to have a function in the same file as a script, the function must go at the bottom. Until about version 2016b, the function had to go in a totally separate file.

It needs to be like this:

%project2.m

tols = [0.1 0.05 0.01 0.005 0.001];

for i = 1 : 5

      tols = [0.1 0.05 0.01 0.005 0.001];
      [errors(i), totalSteps(i)] = psum(tols(i));
  end

loglog(errors, tols, totalSteps, tols)

%psum.m
function[sum, steps] = psum(tol)

sum = 1.0;

steps = 1;

while abs(sum-pi^2/6.0) >= tol

      steps = steps +1;
      sum = sum + 1 / steps ^2;
  end

end

[Arjun Panyam]

For some reason, it's still giving me the same error

[David Fletcher]

Probably no comfort, but it works on my computer.

[David Fletcher]

Not much I can suggest other than you could try moving the function to a totally separate file and calling it from your script.

[Arjun Panyam]

What version of MATLAB are you using? I'm using 2017b.

[Walter Roberson]

If I save the text that David provided into a single file and run it with R2018a then there is no difficulty. I would not expect any difficulty with R2017b either.

[David Fletcher]

Much like Walter I'm on R2018a, but I have just tried it on R2017a and it works fine on that as well.

*Just a thought - you've not called the file psum by any chance?

[Arjun Panyam]

It's on a script called Project2 with other programs under headers %%Question 1 and %%Question 2, for some reason when I run just the %%Question 3 section of the program in a seperate script, it does not come up with the same error.

[Walter Roberson]

You cannot use the structure

   some script
   function
   some more script

The %% sections are not treated separately: the restrictions apply to the entire file, that if you have a mix of function and script then the function must go at the bottom.