mod-inv ( x n -- y ) (original) (raw)
mod-inv ( x n -- y )
Factor handbook » The language » Numbers » Mathematical functions » Integer functions
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Inputs
x | an integer |
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n | an integer |
Outputs
y | an integer |
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Word description
Outputs a positive integer y such that x*y = 1 (mod n).
Errors
Throws an error if x is not invertible modulo n.
Examples
USING: math.functions prettyprint ; 173 1119 mod-inv .
815
USING: math prettyprint ; 173 815 * 1119 mod .
1
Definition
USING: kernel math math.functions.private ;
: mod-inv ( x n -- y )
[ gcd 1 = ] 1check
[ >positive-mod ] [ non-trivial-divisor ] if ; foldable
flushable