bmodinv

Return the modular inverse of $x mod $y.

Synopsis

my $x = Math::GMP->new(5);
my $inv = $x->bmodinv(7);      # 3, because 5 * 3 == 1 (mod 7)

When $x has no inverse modulo $y (i.e. gcd($x, $y) != 1), returns 0. Behaviour is undefined when $y is 0.

Edge cases

• bmodinv returning 0 is ambiguous: 0 is never a valid inverse, so treat it as “no inverse exists”.