CLCS
Function

gcd

gcd &rest integers ⇒ greatest-common-denominator

Arguments and Values

integeran integer.
greatest-common-denominatora non-negative integer.

Description

Returns the greatest common divisor of integers. If only one integer is supplied, its absolute value is returned. If no integers are given, gcd returns 0, which is an identity for this operation.

Examples

 (gcd) ⇒  0
 (gcd 60 42) ⇒  6
 (gcd 3333 -33 101) ⇒  1
 (gcd 3333 -33 1002001) ⇒  11
 (gcd 91 -49) ⇒  7
 (gcd 63 -42 35) ⇒  7
 (gcd 5) ⇒  5
 (gcd -4) ⇒  4

Exceptional Situations

Should signal an error of type type-error if any integer is not an integer.

See Also

lcm

Notes

For three or more arguments,

 (gcd b c ... z) ≡ (gcd (gcd a b) c ... z)