Why do i get ""

Hello! I am trying to do a function that basically does this:

getInterpolationArrays(2,8)

x = [1, 3, 5, 7]

xp = [2, 4, 6, 8]

getInterpolationArrays(5,8)

x = [1, 6]

xp = [2, 3, 4, 5, 7, 8]

The array xp is like a "complement" of x. I writed the function below, but i get the following warning: Variable xp appears to change size on every loop iteration. I dont know how to solve it. Thank you for the response!

function [x, xp] = getInterpolationArrays(days, size)
    x = 1:days:size-1;
    n = length(x);
    xp = [];
    for i=1:size
        if(ismember(i,x) == 0)
            xp = [xp, i];
        end
    end
end

Answer 1

[Voss]

It's only a warning (not an error), so you don't have to solve it.

getInterpolationArrays is written such that xp is constructed element-by-element, so of course xp changes size as the loop iterates.

If you want to rewrite getInterpolationArrays to avoid that warning, you could do it like this:

[x,xp] = getInterpolationArrays(2,8)

x = 1×4

1 3 5 7

xp = 1×4

2 4 6 8

[x,xp] = getInterpolationArrays(5,8)

x = 1×2

1 6

xp = 1×6

2 3 4 5 7 8

function [x, xp] = getInterpolationArrays(days, size)
    x = 1:days:size-1;
    xp = 1:size;
    xp = xp(~ismember(xp,x));
end

[Matías Bozo Pizarro]

Thank you! I didn't find a way to make it so simple.

[Voss]

You're welcome!