Hi Bin,
You can find distance between a query point and multiple other points in the following 2 ways -
tic;d = x-Y
a = abs(d(:,1))+abs(d(:,2));toc
tic;
for i=1:242
for j=1:2
d(i,j) = x(i,j) - Y(j)
end
b(i) = abs(d(i,1)) + abs(d(i,2))
end
toc;
Here, x is the array of 2-D points and Y is the 1-by-2 query point and you have 242 points in x.
Also, you would observe that the first way is almost 50x more efficient than the second way. This is because the first way uses vectorization, unline the second way which uses loops.
You can then apply median function to find median, or compare each distance with alpha. Note that this can also be done through vectorization.
