error when using min function

I have a 180x180 matrix of random integers and I am simply trying to find the smallest element but everytime I run the code it says "Index exceeds matrix dimensions." and refers to my last line of code. Any suggestions?

N1 = randi([1,500],45,45);
N2 = randi([25,1000],45,45);
N3 = randi([100,2200],45,45);
N4 = randi([5,700],45,45);
N5 = randi([100,500],45,45);
N6 = randi([800,3500],45,45);
N7 = randi([1000,10000],45,45);
N8 = randi([15,1000],45,45);
N9 = randi([250,900],45,45);
N10 = randi([5000,11000],45,45);
N11 = randi([1750,9000],45,45);
N12 = randi([25,890],45,45);
N13 = randi([2000,7500],45,45);
N14 = randi([200,2300],45,45);
N15 = randi([25,750],45,45);
N16 = randi([50,1323],45,45); 
N = [N1  N2  N3  N4;
     N5  N6  N7  N8;
     N9  N10 N11 N12;
     N13 N14 N15 N16];

M = min(N(:))

Answer 1

[David Goodmanson]

Hi Andrew, this is a hypothetical answer but it may be that you have, somewhere else, defined 'min' to be a variable .e.g min = 4 or similar.

[John D'Errico]

100% on that.

[Gökberk Yar]

Thanks a lot, you have just saved my friend's computer vision lab.

Answer 2

[Pintu Saini]

If someone uses the min() function inside a matlab function like Histogram normalisation, then also it shows error.

So, error comes if we write this way: min=min(img(:));

To get rid of this, we can do: MIN=min(img(:));

Just don't use the variable name same as that of function name.

Thanks.