interval-bitand ( i1 i2 -- i3 )
Factor handbook » The language » Numbers » Intervals » Interval arithmetic

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Vocabulary
math.intervals

Inputs

i1	an interval
i2	an interval

Outputs

i3	an interval

Word description
Outputs an interval containing all possible values obtained by applying bitand to elements of i1 and i2.

Definition

USING: accessors combinators kernel math math.intervals.private
sequences ;

IN: math.intervals

: interval-bitand ( i1 i2 -- i3 )
    [
        {
            {
                [ 2dup [ interval-nonnegative? ] both? ]
                [ min-upper-bound [0,b] ]
            }
            {
                [ 2dup [ interval-nonnegative? ] either? ]
                [
                    dup interval-nonnegative?
                    [ nip ] [ drop ] if to>> first [0,b]
                ]
            }
            [
                [ min-lower-bound bit-weight neg ] [
                    2dup [ interval-negative? ] both?
                    [ min-upper-bound ] [ max-upper-bound ] if
                ] 2bi [a,b]
            ]
        } cond
    ] do-empty-interval ;