Why do I keep getting an undefined function for 'deter'?

Trying to find the determinant of an upper triangular matrix without using the built-in det function. Why do I keep getting an undefined function error for 'deter'?

function d = deter (U)

n = 4;

A = rand(n,n);

d = prod(diag(U));

end

[James Tursa]

What is the purpose of creating the A matrix inside this function?

Answer 1

[KALYAN ACHARJYA]

function d=deter (U)
n=4;
A=rand(n,n);
d=prod(diag(U));
end

Save the function in new matlab file (save as deter.m), Next call the function from command window or another main script. Please note that you have pass the input arguments (U) to the function form command window or another main Matlab script as shown below.

Hope it helps!