In order to call R from the SAS system, the R statistical software must be installed on the SAS workspace server and the RLANG system option must be enabled. (See the section The RLANG System Option.)
Chapter 10: Submitting SAS Statements, describes how to submit SAS statements from PROC IML. Submitting R statements is similar. You use a SUBMIT statement, but add the R option: SUBMIT / R. All statements in the program between the SUBMIT statement and the next ENDSUBMIT statement are sent to R for execution. The ENDSUBMIT statement must appear on a line by itself.
The simplest program that calls R is one that does not transfer any data between the two environments. In the following program, SAS/IML is used to compute the product of a matrix and a vector. The result is printed. Then the SUBMIT statement with the R option is used to send an equivalent set of statements to R.
proc iml;
/* Comparison of matrix operations in IML and R */
print "---------- SAS/IML Results -----------------";
x = 1:3; /* vector of sequence 1,2,3 */
m = {1 2 3, 4 5 6, 7 8 9}; /* 3 x 3 matrix */
q = m * t(x); /* matrix multiplication */
print q;
print "------------- R Results --------------------"; submit / R; rx <- matrix( 1:3, nrow=1) # vector of sequence 1,2,3 rm <- matrix( 1:9, nrow=3, byrow=TRUE) # 3 x 3 matrix rq <- rm %*% t(rx) # matrix multiplication print(rq) endsubmit;
The printed output from R is automatically routed to the SAS/IML Studio output window, as shown in Figure 11.1. As expected, the result of the computation is the same in R as in SAS/IML.