SAS Companion for the OpenVMS Operating Environment

Numeric Variables in the Alpha Environment

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 the SAS System under OpenVMS Alpha, the data type of numeric variables is IEEE double precision or T_FLOATING. The precision of an OpenVMS Alpha 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 Alpha T_FLOATING numbers, you can specify a minimum length of 3 bytes using the LENGTH statement in the DATA step. However, with VAX D_FLOATING numbers, the minimum length you can specify is 2 bytes.

Significant Digits and Largest Integer for SAS Variables in the Alpha Environment shows the number of nontruncated significant digits and 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 Alpha 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

***Significant Digits and Largest Integer for SAS Variables in the Alpha 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

For more information about converting 2-byte numeric variables from VAX environments to 3-byte numeric variables for use in Alpha environments, see the procedure VAXTOAXP.

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