Question

for i=0:255
m(i+1)=sum((0:i)'.*p(1:i+1)); end

What is happening can anyone explain. p is an array of size 256 elements same as m.

Answer 1

p = (0:255)';
m = zeros(1,256);
for i=0:255
    m(i+1)=sum((0:i)'.*p(1:i+1)); 

end

m[i+1] contains the scalar product of [0,1,2,..,i] with (p[1],...,p[i+1])

You can write it as :

p = (0:255);
m = zeros(1,256);
for i=0:255
    m(i+1)=sum((0:i).*p(1:i+1)); 

end

Or:

p = (0:255);
m = zeros(1,256);
for i=0:255
    m(i+1)=(0:i)*p(1:i+1)'; 

end

In case you don’t recall, that is the definition of scalar product