Scripting Guide - SAS

224 Programming Methods Chapter 8
Additional Numeric Operators
Figure 8.3 Example of an Encrypted Data Table Script
Additional Numeric Operators
Derivatives
JSL also offers several categories of operations that do not make much sense in the context of the formula
editor: matrix operations and numeric derivatives of functions. Algebraic derivatives are also available.
The basic arithmetic operators can also be used with matrix arguments for matrix-wise addition,
subtraction, and so on. Matrices also have a few special operators for elementwise multiplication and
division, concatenation, and indexing. See the chapter “Matrices” on page 137 in the “Data Structures”
chapter, for details.
JSL has three internal operators (not all available in the calculator) for taking derivatives.
Derivative takes the first derivative of an expression with respect to names you specify in the second
argument. A single name might be entered as this second argument; or multiple values can be specified in a
list, in other words, surrounded by braces.
Note: Derivative is also available as an editing command inside the formula editor (calculator), located
on the drop-down list in the top center of the formula editor (above the keypad). To use it, highlight a single
variable in the expression (to designate which variable the derivative should be taken with respect to), then
select the Derivative command from the menu. The whole formula is replaced by its derivative with respect
to the highlighted name.
In scripts, the easiest way to use the function is with a single name. In this example, we first show the
mathematical notation and then the JSL equivalent.
For fx () x 3
d 3
= , the first derivative is f ’(x) or x = 3x 2 .
dx
result = derivative(x^3, x); show(result);
result = 3 * x ^ 2
If you want an efficient expression to take the derivative with respect to several variables, then the variables
are specified in a list. The result is a list containing a threaded version of the original expression, followed by