US online retail spending (% change on a year earlier): During November to January, the spending 
consistently superior for 2006 than other years. 2008 was lowest in most of the weeks and 
2009 was slightly higher than 2008.  
Error using .*
Matrix dimensions must agree.

Error in plotSpotlight (line 30)
    output = repmat(a,[1 1 3]).*single(im)/255;

Error in plot_individual_user_maps (line 49)
        [heat] = plotSpotlight(im,heatmap,3);