Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

Hello guys, this is the code taken from Nuruzzaman Faruki, from this video: https://www.youtube.com/watch?v=WoLBeWclYxo

It gives error down below. There is only 3 .m files, it is very short. Please help me. Exact code worked in his video but doesn't work in mine. I am using r2019b by the way.

This is Sigmoid.m:

function y= Sigmoid(x)
y= 1/(1+exp^(-x));
end

This is SGD_method.m:

function Weight= SGD_method(Weight, input, correct output)
alpha=0.9;
N=4;
end
for k=1:N 
transposed_Input= input(k, :)';
d=correct_Output(k);
weighted_Sum=Weight*transposed_Input;
output=Sigmoid(weighted_Sum);
error= d - output;
delta= output* ( 1 - output) * error;
dWeight = alpha * delta * transposed_Input;

Weight(1)= Weight(1)+dWeight(1);
Weight(2)=Weight(2)+dWeight(2);
Weight(3)=Weight(3)+dWeight(3);
end
end

And this is the Training.m:

 input=[0 0 1;
	0 1 1;
	1 0 1;
	1 1 1;
	];
correct_Output=[0
		0
		1
		1
		];
Weight=2*rand(1, 3) - 1;
for epoch = 1:10000
Weight= SGD_method(Weight, input, correct_Output);
end

It gives this error:

>> Training
Error: File: SGD_method.m Line: 5 Column: 1
This statement is not inside any function.
 (It follows the END that terminates the definition of the function "SGD_method".)

Error in Training (line 13)
Weight= SGD_method(Weight, input, correct_Output);

[Stephen23]

Your code is badly aligned. Badly aligned code is one way that beginners hide basic bugs and errors in their code (e.g. the cause of the error in your code). You should align your code consistently, it would make it much easier to spot basic errors like this one.

I recommend using the default MATLAB Editor settings. You can also align existing code using the Editor: select the code text, press ctrl+i.

Answer 1

[Stephen23]

function Weight= SGD_method(...)
alpha=0.9;
N=4;
end % <--------- DELETE THIS LINE!
for k=1:N 
...

[Mahmut Dönmez]

Thanks, it stopped giving errors but in the video it created a .mat file but it didn't do for me. Why is that? Our teachers won't help at all, neither they even taught us in the first place.

[Steven Lord]

There's no call to save anywhere in the code you posted, so I would have been surprised had it created a MAT-file.

It sounds a bit like you're trying to learn MATLAB by watching videos on YouTube. If that's the case, might I suggest that you take the free two hour MATLAB Onramp tutorial available from the Tutorials item on the Support section of this website? Click on the link Support at the top of this page then go to Tutorials. The MATLAB Onramp tutorial is an interactive course designed to teach you the fundamentals of working with MATLAB