function [eigvect,eigval]=pca_n(data,n)
% function [eigvect,eigval]=pca_n(data,n)
%
% Input:
%   data is a matrix whose columns are data points.
%   n is the number of eigenvectors to return.
%
% eigenvalues are sorted in descending order
%
% D. Wingate 11/02/06
%

data_c = data - repmat( mean(data,2), 1, size(data,2) );

[U,S,V] = svds( data_c, n );

eigvect = V;
eigval = diag(S);

return;