Graphing Model Results

To look at the results of a model graphically, it is convenient to create special files to be executed by an add command. These files may be called “show” files and denoted with the extension .SHW to make them easy to find and identify.

To make a show for a historical simulation, we need to assign the bank with the actual data, usually called the BWS bank, and another with the results of the simulation, which we may assume was called HISTSIM. We do so with the commands:

bank bws c
bank histsim b

Then we have a number of (ti)tle, gname, and (gr)aph commands to make the graphs. We can put all of these in an add file, such as HIST.SHW, when we execute the file by

add hist.shw

A simple HIST.SHW file is may look like this:

bank histsim b
bank bws c
gdates 1980.1 2001.1
title GDPR -- REAL GROSS DOMESTIC PRODUCT
gname gdpR
gr b.gdpR c.gdpR
title cR -- CONSUMPTION
gname gcR
gr b.cR c.cR
title vfR -- GROSS PRIVATE FIXED INVESTMENT
gname vfR
gr b.vfR c.vfR

and so on for as many series as we want to graph. The gname lines give the name of the file (to which .WMF will be added) if the user clicks save in the panel that pops up to control the execution of the add command. In the gr lines, the “b.” and “c.” tell G7 to look for these series in and only in bank ‘b’ or bank ‘c’, respectively. The effect of this command, therefore, is to graph the gdpR series from histsim as the first line, the red line, and then to graph the gdpR series from bws as the second, the blue line. The result is a graph with the actual historical course of gdpR shown in blue (true is blue) and the model’s calculated gdpR shown in red.