LI-COR LI-6400, Manual

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LPL Topics
Math Functions
23-20 Using the LI-6400
23
The mathematical functions in LPL can operate not only on values, but also
on collections of values. For example, consider the addition operator
+ as
used in Figure 23-10 below
The
+
operator obviously does more than blindly add whatever is on the stack
together. It checks to see what type of objects are sitting on the stack, and op-
erates accordingly. Thus, we can not only add two numbers together, we can
also sum an array, add a constant to an array, or add two arrays together ele-
ment by element, all with the keyword
+
.
In general, LPLÕs math functions can be classified as Two Object Transforms
(e.g.
+ ), or Single Object Transforms (e.g. ABS , absolute value).
Single Object Transforms
Single Object Transforms can operate on values, addresses of numeric vari-
ables, or arrays, so there are a variety of combinations of things that can be
on the stack when a Single Object Transform executes. We illustrate the pos-
sible before and after stack status by the following shorthand:
:INT
iArray[5] {1 2 3 4 5}
:FLOAT
floatVal 1.234
fArray[5] {10.1 11.1 12.1 13.1 14.1}
:FCT
Main
{
/* Add two values 11.734 left on the stack */
10.5 7
+
/* Add a constant to an array whose address is left on the stack.
iArray = {6 7 8 9 10} */
iArray 5
+
/* Add Two Arrays. fArray address left on stack.
fArray = {16.1 18.1 20.1 22.1 24.1} */
fArray iArray
+
/* Add value to variable, by address.
floatVal address left on stack,floatVal = 6.234 */
&floatVal 5
+
/* Compute the sum of an array.
(6+7+8+9+10) = 30 is left the stack */
0 iArray
+
}
Figure 23-10. Various uses of the
+
operator.