How can I solve the following error?

For an arbitrary matrix, I want to sum the entries of each row of it.

I use the command sum(A,2) for the square matrix A. But I encounter the following error

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

Answer 1

[Star Strider]

Somewhere you have a variable named ‘sum’ and this is throwing the error.

The solution is to re-name the variable to something else that makes sense in the context of the code and does not overshadow any MATLAB function names.

Answer 2

[Fangjun Jiang]

Most likely, you have a variable called "sum". Clear it first and then run your code

clear sum;
A=magic(5);
sum(A,2)

ans = 5×1

65 65 65 65 65