Error: Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

Hey guys

I've written some code to compute cost function at various theta, as follows:

h = X * theta;

J = [1/(2*m)] * sum[(h-y).^2];

All variables have been defined. Upon running the code above, I'm getting the following error message:

Error: Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

I have no experience with Matlab, so any help would be appreciated!

Thanks

Answer 1

[Rajanya]

Hi @Mihir Choughule,

'sum' is a function and needs to be called with parentheses (not square brackets [.]) -

sum((h-y).^2)

Thanks.

[Stephen23]

See also: https://www.mathworks.com/help/matlab/learn_matlab/calling-functions.html