Visualizing time series data code extension

library tsmt;
 
//Load data
fname = getGAUSShome $+ "pkgs\\tsmt\\examples\\wpi1.dat";
 
//Load data
y = loadd(fname, "ln_wpi");
 
//Take first differences
y_diff = vmdiffmt(y, 1);
 
//Set up plot format
struct plotControl myplot;
myplot = plotGetDefaults("XY");
 
//Turn off grid
plotSetGrid(&myPlot, "off");
 
//Title
plotSetTitle(&myPlot, "U.S. World Price Index ",
               "Helvetica Neue", 18);
 
//Y-axis label
plotSetYLabel(&myPlot, "ln(wpi)",
                "Helvetica Neue", 14);
 
//Start Date
dtstart = 196001;
 
//Frequency (quarterly)
freq = 4;
 
//PlotLayout
plotlayout(2, 1, 1);
 
//Plot level data
plotTS(myPlot, dtstart, freq, y);
 
//PlotLayout
plotlayout(2, 1, 2);
 
//Change itle
plotSetTitle(&myPlot, "",
               "Helvetica Neue", 18);
 
//Change Y-axis label
plotSetYLabel(&myPlot, "First differences ln(wpi)",
                "Helvetica Neue", 14);
 
//Plot level data
plotTS(myPlot, dtstart, freq, y_diff);