matrix multiply by array xi=xj

Hi, All!

say, i have a matrix:

eij= [0 1 0 1;1 0 1 1;0 1 0 1;1 1 1 0];
x1=1; x2=2; x3=3; x4=4;

how can i make array xj and xi for this function

for i=1:1:4 and j=1:1:4
xi = xj

Ai =

i hope the answer would be like this:

A1= 0(1 - 1) + 1(2 - 1) + 0(3 - 1) + 1(4 - 1)=4
A2= ...; A3=..., A4=...

i am trying to use repmat function but i am stuck. maybe anyone has better solution?

Answer 1

[KSSV]

e = [0 1 0 1;1 0 1 1;0 1 0 1;1 1 1 0];
x = [1 2 3 4] ; 
A = zeros(size(e)) ; 
for i = 1:4
  for j = 1:4
    A(i,j) = e(i,j)*(x(i)-x(j)) ; 
  end
end
A = sum(A,2)

[Nur Amalina]

got it. thank you!

Answer 2

[Bhaskar R]

x = 1:4;
eij= [0 1 0 1;1 0 1 1;0 1 0 1;1 1 1 0];
tmp  =0;
for i = 1:4
    for j = 1:4
        tmp  =tmp + eij(i, j)*(x(j)-x(i));
    end
    A(i) = tmp;
end