The UseRule( name ) command sets the default rounding rule used by ScientificErrorAnalysis to the rule name for the current session.

To set the default rounding rule for all future Maple sessions, add the UseRule command to your Maple initialization file. For more information, see Create Maple Initialization File.

The rule name may require an index.

If the rule name is specified with an index, UseRule checks the validity of the index. If the index is invalid, the stored procedure for the rule throws an error and the default rule is not changed.

To check, the rule is applied to Quantity( 0.0, 1.0 ). If no error is triggered, the result is discarded.

For more information on predefined rules in ScientificErrorAnalysis, see Predefined Rounding Rules.

$\mathrm{with}\left(\mathrm{ScientificErrorAnalysis}\right)\:$

$\mathrm{e1}≔\mathrm{Quantity}\left(1.2088\,0.563\right)$

$\mathrm{e1}≔\mathrm{Quantity}\left(1.2088\,0.563\right)$

$\mathrm{UseRule}\left(\mathrm{round}\left[2\right]\right)$

$\mathrm{ApplyRule}\left(\mathrm{e1}\right)$

$\mathrm{Quantity}\left(1.21\,0.56\right)$

$\mathrm{UseRule}\left(\mathrm{round}\left[0\right]\right)$

Error, (in ScientificErrorAnalysis:-UseRule) invalid index to `round`

$\mathrm{UsingRule}\left(\right)$

${\mathrm{round}}_2$