Creating a function for a two-dimensional array

I have a function:

function [ filled ] = travelDistance( blank )
%TRAVELDISTANCE
%   blank: two-dimensional array comprised of -1s, 0s, and 1s
%   filled: blank that is modified (replace every 0 in blank with its
%   distance to the nearest 1, tarting at 2, traveling along cardinal
%   directions without passing through a -1 value)

    function d = xyspace(A,x,y)
        idx1=find(ismember(A,x));
        idx2=find(ismember(A,y));
        x=union(idx1,idx2);
        whichset=ismember(x,idx1)+2*ismember(x,idx2);
        idx=diff(whichset)>0;
        d=x([false,idx])-x([idx,false]);
    end

filled=xyspace(blank,0,1);

end

but this function doesn't work on two-dimensional arrays and receives an error:

Error using horzcat
Dimensions of matrices being concatenated are
not consistent.

Error in travelDistance/xyspace (line 14)
      d=x([false,idx])-x([idx,false]);
Error in travelDistance (line 17)
filled=xyspace(blank,0,1);

How do I write the function to apply to 2x2 arrays?

Answer 1

[Walter Roberson]

find() returns column vectors, and [false, column_vector] is going to fail. [false; column_vector] would work.