MATLAB: Question related to vectorized matrix operation.

matlab matrix vector operations

i have two matrices A and B; A is say (Nx3) where N is rather large like 1000+… B is (nx2) where n is rather smaller of the order 10 or so.. but it does not matter it is smaller than A row size. i would like to compute
    for i = 1:N
       D = ( A(i,1)- B(1:n,1) )^2 + (A(i,2) - B(1:n,2)^2 )  
    end
for e.g. if N is 4, and n =2 then D = a [4×2] matrix…
I am able to perform this using for loops without much difficulty but would like to try using the vectorized Matrix operations instead for improving the performance and speed. Thanks in advance.

Best Answer

>> A = randi(9,4,3)
A =
     4     2     9
     9     4     4
     5     4     8
     4     2     8
>> B = randi(9,3,2)
B =
     3     2
     6     4
     3     1
>> D = bsxfun(@minus,A(:,1),B(:,1).').^2 + bsxfun(@minus,A(:,2),B(:,2).').^2
D =
    1    8    2
   40    9   45
    8    1   13
    1    8    2
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