Call on function that takes in 2 variables multiple times

so my function takes in one double variable and one 1by3 array

it outputs a 1by3 array

I was wondering if theres a way to pass in a N by 1 double, with a N by 3 array, and have it output a N by 3 array without using a loop, my code currently looks like this:

N=100
input_doubles = rand(N,1)
input_vectors = rand(N,3)
output_vectors = zeros(length(input_doubles),3);
for i = 1:1:length(input_doubles)
    output_vectors = example_func(input_doubles(i), input_vectors(i, :))
end

is there a way to not use a for loop? but still call the function individually and collect it's output into rows?

Answer 1

[Matt J]

You can hide the loop with arrayfun, but it won't speed things up.

output_vectors = cell2mat(arrayfun(@(i) {example_func(input_doubles(i), input_vectors(i, :)},...
                                        (1:length(input_doubles))'  );

Answer 2

[William Rose]

@Spacestudent112233,

You can write a funciton that returns values whose size varies as the size of the inputs vary. I am not sure if that is acceptable to you. Here is an example.

function z = example_func(x,v)
%EXAMPLE_FUNC Returns vector or array.
%   If size(x)=1x1 and size(v)=1x3, then size(z)=1x3.
%   If size(x)=Nx1 and size(v)=Nx3, then size(z)=Nx3.
%  See Matlab Answers post by Spacestudent112233, 2022-11-10.
z=x.*v;
end

>> disp(example_func(2,[4,5,6]))

8 10 12

>> disp(example_func([2;4;6;8],[1,2,3;10,20,30;100,200,300;1000,2000,3000]))

2 4 6

40 80 120

600 1200 1800

8000 16000 24000

If you pass it a double and a vector, it retruns a vector.

Example 1 above: It returns 1x3 when it recieves 1x1 and 1x3.

Example 2, above: N=4. It returns Nx3 when it receives Nx1 and Nx3.

This is what you requested. Good luck.