Programming the true range in Wilder's DMI
by Jim Summers, Ph.D.
The March column described the fundamentals of macros. The February column detailed some major
points about Wilder's DMI and the system based on it. This time the action gets underway in earnest.
While the material is still relatively elementary now, veteran Lotus programmers should at least skim this
material. Some of the techniques appear in none of the five books I own on using Lotus. One of them is
critical to successful processing of large amounts of data such as technical analysis requires.
Fundamentally, Wilder's DMI system develops two measurements: (1) the true range in which prices
move and (2) the amount of the movement that was directional, whether up or down. Once these two
pieces are defined, everything else builds on them.
Now we begin the work of programming in Lotus 1-2-3 in order to have it calculate the first piece of the
DMI system, the true range (TR1). This and the calculation of directional movement are the more
complex calculations in the system. If you can master them, you'll find the rest easy. Because the formula
is so lengthy, much care will be taken in it's development. Let's start with the definition of TRI.