apply bsxfun and arrayfun to every row of a matrix

There is two matrix, A and B with size m by 4 and n by 4 respectively. My question is how to apply a function f, which takes two 1x4 vectors as input, on every row of A and B. The result will be a matrix with size mxn. The element [i, j] in 'result' is f(A(i, :), B(j, :)).

For example:

A = rand(3, 4);
B = rand(5, 4);
for i = 1 : 3
    for j = 1 : 5
        result(i, j) = rectint(A(i, :), B(j, :));
    end
end

Can I use bsxfun or arrayfun to do this job?

[Matt J]

Does f() support inputs like

    f(A(i,:), B)

and

    f(A,B(j,:))

[Azzi Abdelmalek]

Can you give an example?

[zhang]

I've gave an example now. Please have a look at it.

Answer 1

[Matt J]

In your example, there is no need to use bsxfun or arrayfun. rectint(A,B) will produce exactly the matrix you are looking for.

[zhang]

Thanks, just know that rectint can do it directly. Then there is no need to use bsxfun. But what about others?

[Matt J]

It depends on the answers to the questions I asked you above.

[Azzi Abdelmalek]

zhang, result = rectint(A, B) and your code give the same size but not the same values

[zhang]

@Matt J, Thanks so much for the help. Let's assume f can support what you asked. One more question, if A is a 1x4 and B is mx4, is there any way to apply function f(just support f(1x4, 1x4))to each row of A and B without using loop

[Matt J]

If your f() supports what I asked about, then bsxfun can be used

I=1:size(A,1);
J=1:size(B,1);
F=@(i,j) f(A(i,:), B(j,:));

bsxfun(F,I.',J);

if A is a 1x4 and B is mx4, is there any way to apply function f(just support f(1x4, 1x4))to each row of A and B without using loop

Not really. You can hide the loop inside arrayfun, but it won't be faster

arrayfun(@(j) f(A,B(j,:)) , J.');