LI-COR LI-6400, Manual

Page: 410 / 846

Defining User Variables
Writing and Modifying ComputeList Files
15-8 Using the LI-6400
15
¥
Other User Variables
These are referenced by ID number, preceded by a single # or (starting in
OPEN 3.2) the letter
u . For example, #101 or u101.
¥
LPL Functions and Operators
Table 15-3 on page 15-15 provides a list of useful functions and operators.
¥ UREM() or UCON()
These specify the variable to be user input, and not computed. This is de-
scribed in
User Defined Constants and Remarks on page 15-12.
¥ The NOASSIGN marker
When OPEN processes a ComputeList, it generates code for a function that
will execute every time user variables are computed. Each user variable that
you define causes a variable named
unnn to be created (where nnn is the ID
number of your variable. Thus, u20 is the variable name of #20). The code
that is generated will have a line for each variable assigned to its equation
string. Thus, if the equation string for ##20 was
"10 * #15"
, the line for u20
would appear as in Figure 15-4.
Note that Ò#15Ó becomes Òu15Ó. You can write it either way.
If you donÕt want this automatic assignment taking place, it can be suppressed
with the word NOASSIGN. Suppose, for example, we wanted a variable that
indicated 1 for photosynthesis, or 0 for respiration. (I can think of no good
reason to do this, but it illustrates the point.) You could define it this way:
##102 "Flag" "1 if photo, 0 if resp"
" NOASSIGN
if (#30 > 0)
u102 = 1
ELSE
u102 = 0
THEN "
The word NOASSIGN in the first line of the equation string will prevent the
u20 = 10 * u15
Éto your equation System adds thisÉ
Figure 15-4. When building the code for each user variable, the
system makes the equation by inserting the variable name and
an = sign before your equation.