Function sorensen_dice
fn sorensen_dice(a: &str, b: &str) -> f64
Calculates a Sørensen-Dice similarity distance using bigrams. See https://en.wikipedia.org/wiki/S%C3%B8rensen%E2%80%93Dice_coefficient.
use sorensen_dice;
assert_eq!;
assert_eq!;
assert_eq!;
assert_eq!;
assert_eq!;