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: pcaVisualize.m
    path of file: ./repos/MCITF/Code/MCITF/EdgeBox/piotr_toolbox/toolbox/classify
    
    the code of the file until where you have to start completion: function varargout=pcaVisualize( U, mu, vars, X, index, ks, fname, show )
% Visualization of quality of approximation of X given principal comp.
%
% X can either represent a single element (a single image or video), or a
% set of elements. In the latter case, index controls which element of X to
% apply visualization to, if unspecified it is chosen randomly.
%
% USAGE
%  varargout=pcaVisualize(U, mu, vars, X, [index], [ks], [fname], [show])
%
% INPUTS

    
function varargout=pcaVisualize( U, mu, vars, X, index, ks, fname, show )
% Visualization of quality of approximation of X given principal comp.
%
% X can either represent a single element (a single image or video), or a
% set of elements. In the latter case, index controls which element of X to
% apply visualization to, if unspecified it is chosen randomly.
%
% USAGE
%  varargout=pcaVisualize(U, mu, vars, X, [index], [ks], [fname], [show])
%
% INPUTS
%  U           - returned by pca.m
%  mu          - returned by pca.m
%  vars        - returned by pca.m
%  X           - Set of images or videos, or a single image or video
%  index       - [] controls which element of X to aplply visualization to
%  ks          - [] ks values of k for pcaApply (ex. ks=[1 4 8 16])
%  fname       - [] if specified outputs avis
%  show        - [1] will display in figure(show) and figure(show+1)
%
% OUTPUTS
%  M           - [only if X is a movie] movie of xhats (see pcaapply)
%  MDiff       - [only if X is a movie] movie of difference images
%  MU          - [only if X is a movie] movie of eigenmovies
%
% EXAMPLE
%
% See also PCA, PCAAPPLY
%
% Piotr's Computer Vision Matlab Toolbox      Version 2.30
% Copyright 2014 Piotr Dollar.  [pdollar-at-gmail.com]
% Licensed under the Simplified BSD License [see external/bsd.txt]

% sizes / dimensions
siz = size(X);  nd = ndims(X);  [D,r] = size(U);
if(D==prod(siz) && ~(nd==2 && siz(2)==1)); siz=[siz, 1]; nd=nd+1; end