interval-abs ( i1 -- i2 )
Factor handbook » The language » Numbers » Intervals » Interval arithmetic

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Vocabulary
math.intervals

Inputs

i1	an interval

Outputs

i2	an interval

Word description
Absolute value of an interval.

Examples

USING: math.intervals prettyprint ; -11 -10 [a,b] interval-abs .
T{ interval { from { 10 t } } { to { 11 t } } }

Definition

USING: combinators kernel sequences ;

IN: math.intervals

: interval-abs ( i1 -- i2 )
    {
        { [ dup empty-interval? ] [ ] }
        { [ dup full-interval? ] [ drop [0,inf] ] }
        {
            [ 0 over interval-contains? ]
            [
                (interval-abs) { 0 t } suffix
                points>interval nan-not-ok
            ]
        }
        [ (interval-abs) points>interval nan-not-ok ]
    } cond ;