You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_cross.m
    path of file: ./repos/spm12
    
    the code of the file until where you have to start completion: function [Y] = spm_cross(X,x,varargin)
% Multidimensional cross (outer) product
% FORMAT [Y] = spm_cross(X,x)
% FORMAT [Y] = spm_cross(X)
%
% X  - numeric array

    
function [Y] = spm_cross(X,x,varargin)
% Multidimensional cross (outer) product
% FORMAT [Y] = spm_cross(X,x)
% FORMAT [Y] = spm_cross(X)
%
% X  - numeric array
% x  - numeric array
%
% Y  - outer product
%
% See also: spm_dot
%__________________________________________________________________________
% Copyright (C) 2015 Wellcome Trust Centre for Neuroimaging

% Karl Friston
% $Id: spm_cross.m 7527 2019-02-06 19:12:56Z karl $

% handle single inputs
%--------------------------------------------------------------------------
if nargin < 2
    if isnumeric(X)
        Y = X;
    else
        Y = spm_cross(X{:});
    end