integer-sqrt ( x -- n )
Factor handbook » The language » Numbers » Mathematical functions » Integer functions

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integer-log10 ( x -- n )

Vocabulary
math.functions

Inputs

x	a non-negative rational number

Outputs

n	an integer

Word description
Outputs the largest integer that is less than or equal to the sqrt of m.

Errors
Throws an error if m is negative.

Examples

USING: prettyprint math.functions ; 15 integer-sqrt .
3

Definition

USING: kernel math sequences ;

IN: math.functions

:: integer-sqrt ( x -- n )
    x
    [ 0 ] [
        assert-non-negative bit-length 1 - 2 /i
        :> c 1 :> a! 0 :> d! c bit-length <iota> <reversed> [| s
        |
            d :> e c s neg shift d! a d e - 1 - shift x 2 c *
            e - d - 1 + neg shift a /i + a!
        ] each a a sq x > [ 1 - ] when
    ] if-zero ;