The default length of numeric
variables in SAS data sets is 8 bytes. (You can change the length of SAS numeric
variables with the LENGTH statement in the DATA step.) In SAS under OpenVMS,
the data type of numeric variables is IEEE double precision or T_FLOATING.
The precision of an OpenVMS T_FLOATING value
is expressed as 15 decimal digits, with a range for T_FLOATING numeric
variables of 1.7E+308 to 2.3E-308.
In addition, with OpenVMS
T_FLOATING numbers,
you must specify a minimum length of 3 bytes using the LENGTH statement in
the DATA step.
The issue of numeric precision affects the return values
of almost all SAS math functions and many numeric values returned from SAS
procedures. The following table shows the number of nontruncated significant
digits and the largest integers that can be represented exactly with no loss
of precision for each of the specified lengths.
Significant Digits and Largest Integer for SAS Variables in the OpenVMS on HP Integrity Servers Environment
|
Length in Bytes |
Significant Digits Retained |
Largest Integer Represented Exactly |
|
3 |
3 |
8,191 |
|
4 |
6 |
2,097,151 |
|
5 |
8 |
536,870,911 |
|
6 |
11 |
137,438,953,471 |
|
7 |
13 |
35,184,372,088,831 |
|
8 |
15 |
9,007,199,254,740,991 |
Copyright © 2009 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
