integer-sqrt ( x -- n ) (original) (raw)
integer-sqrt ( x -- n )
Factor handbook » The language » Numbers » Mathematical functions » Integer functions
| Prev: | integer-log10 ( x -- n ) |
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Inputs
| x | a non-negative rational number |
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Outputs
| n | an integer |
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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 ;
:: integer-sqrt ( x -- n )
x
[ 0 ] [
assert-non-negative bit-length 1 - 2 /i
:> c 1 :> a! 0 :> d! c bit-length [| 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 ;