I am implementing the non-vectorized form of the cost function in octave. This is the code from my `.m`

file

```
function computeCost(X, y, theta)
sigma=0;
theta0 = 0;
m = length(y);
for i = 1:m
sigma = sigma+ theta*X(i)-y(i);
end;
J = ((sigma)^2)/2*m;
end;
```

My octave code is:

```
>> X= [1,1; 1,2; 1,3; 1,4;];
>> y= [2;4;6;8];
>> J = computeCost(X, y, 0.5);
```

where `X`

and `y`

are matrices. However, I am getting this output on my CLI Window:

```
Error: computeCost(X, y, 0.5) undefined near line 1, column 5
```

I've checked my code, there is no apparent issue. Is it because Octave does not accept matrices as parameters for its functions?

The answer to your question is clearly YES: The name MATLAB is an abbreviation of

Matrix laboratory. Octave and Matlab are specially designed to facilitate working with matrices.The problem in your code is: Your function definition is incomplete. You have not defined J as return value. The error message you see is a bit missleading because it should state column 10 as place of the error. When you change the first line of your code to

It will work as expected and output the value

`648`

.