The schema is SYSIBM.
The SYSFUN version of the ABS (or ABSVAL) function continues to be available.
Returns the absolute value of the argument. The argument can be any built-in numeric data type.
The result has the same data type and length attribute as the argument. The result can be null; if the argument is null, the result is the null value. If the argument is the maximum negative value for SMALLINT, INTEGER or BIGINT, the result is an overflow error.
ABS(-51234)
returns
an INTEGER with a value of 51234.