|
ROUND |
Control Rounding |
ROUND {ON | OFF}
Use the ROUND directive to control the automatic rounding of values during calculations. If you use the ROUND ON directive, PxPlus will round all values to the PRECISION currently in effect before assigning them to numeric variables. The ROUND OFF directive terminates the rounding process. With ROUND OFF, PxPlus maintains all values at full 18-digit precision.
You can determine if the ROUND is ON or OFF by creating an expression whose value will indicate if rounding is active. The following example uses the default settings in PxPlus:
Example:
round on
a=1.005;
if a=1.005 \
then print "Round is OFF" \
else print "Round is ON"
round off
a=1.005;
if a=1.005 \
then print "Round is OFF" \
else print "Round is ON"
The ROUND directive has no effect if FLOATINGPOINT mode is active.
Rounding Control
The unpredictable rounding of numeric values can cause problems during execution. It is very important to know how rounding works in PxPlus.
If rounding is set to the default, a divide operation in PxPlus will maintain the precision of the starting value; e.g. 1014.475/100 becomes 10.14475, which is rounded to 10.145. The automatic rounding of intermediate results can be turned Off by setting the 'NR' system parameter. Various other types of rounding can be controlled using the 'RN'= system parameter.
PRECISION Change Current Precision
FLOATINGPOINT Switch to Scientific Notation
With ROUND OFF:
precision 2
round off
A=3*(2/3)
print A
->run
2
With ROUND ON:
precision 2
round on
A=3*(2/3)
print A
->run
2.01