MATLAB: Vectorization

vectorization

Dear Community,

Let say I have Matrix M. In Matrix M, each Column is feature of Image. Now what I want to get a binary matrix B by following way.

for given image feature i:

B(1,i) = M(1,i) >= M(2,i);

its mean for each image feature, each cell is compared to its next cell. I want to do it without loops for speed.

diff(M) <= 0

sparse() is the easiest way to handle this. Another way is

A( sub2ind(size(A),B(:, 1),B(:, 2)) = 1;

iwant = diff(M)

If you are adamant about loop:

M = [1;2;4;6;7;8] ;
N1 = [2-1;4-2;6-4;7-6;8-7] ;
N = zeros(length(M)-1,1) ;
for i = 1:length(M)-1
    N(i) = M(i+1)-M(i) ;   
end