I have 2D matrix and I want to cluster it to three groups of data

I have 2D matrix and I want to cluster it to three groups of data based on the range of the data, what clustering method could help me ?

Answer 1

[KSSV]

A = rand(100) ;

set1 = A(A>0 & A<=0.4) ;
set2 = A(A>0.4 & A<=0.8) ;
set3 = A(A>0.8 & A<=1) ;

[Abdullah]

Thanks KSSV for your reply, your method is setting a manual range, I want to use clustering method to cluster the matrix into three groups based on that matrix numbers.