computorv1/src/maths.rs

use std::ops;

//TODO slow ? check Stein's algorithm (binaryGCD)
fn gcd(a: i128, b: i128) -> i128 {
    if b == 0 {
        a
    } else {
        gcd(b, a % b)
    }
}

#[derive(Debug, PartialEq, Clone, Copy)]
pub struct Rational {
    numerator: i128,
    denominator: i128,
}

impl Rational {
    pub fn new(numerator: i128, denominator: i128) -> Self {
        Self {
            numerator,
            denominator,
        }
    }

    pub fn reduce(&self) -> Self {
        let gcd = gcd(self.numerator, self.denominator);
        Rational::new(self.numerator / gcd, self.denominator / gcd)
    }

    pub fn inverse(&self) -> Self {
        Rational::new(self.denominator, self.numerator)
    }

    pub fn left_shift(&self) -> Self {
        Rational::new(self.numerator, self.denominator * 10)
    }

    pub fn simplify(lhs: Rational, rhs: Rational) -> Self {
        let res = Rational::new(lhs.numerator * rhs.denominator, lhs.denominator * rhs.numerator);
        res.reduce()
    }
}

impl ops::Add<Rational> for Rational {
    type Output = Rational;

    fn add(self, rhs: Rational) -> Rational {
        Rational::new(self.numerator * rhs.denominator + rhs.numerator * self.denominator, self.denominator * rhs.denominator).reduce()
    }
}

impl ops::Add<i128> for Rational {
    type Output = Rational;

    fn add(self, rhs: i128) -> Rational {
        Rational::new(self.numerator + rhs * self.denominator, self.denominator).reduce()
    }
}

impl ops::Add<Rational> for i128 {
    type Output = Rational;

    fn add(self, rhs: Rational) -> Rational {
        Rational::new(self * rhs.denominator + rhs.numerator, rhs.denominator).reduce()
    }
}

impl ops::Sub<Rational> for Rational {
    type Output = Rational;

    fn sub(self, rhs: Rational) -> Rational {
        Rational::new(self.numerator * rhs.denominator - rhs.numerator * self.denominator, self.denominator * rhs.denominator).reduce()
    }
}

impl ops::Sub<i128> for Rational {
    type Output = Rational;

    fn sub(self, rhs: i128) -> Rational {
        Rational::new(self.numerator - rhs * self.denominator, self.denominator).reduce()
    }
}

impl ops::Sub<Rational> for i128 {
    type Output = Rational;

    fn sub(self, rhs: Rational) -> Rational {
        Rational::new(self * rhs.denominator - rhs.numerator, rhs.denominator).reduce()
    }
}

impl ops::Mul<Rational> for Rational {
    type Output = Rational;

    fn mul(self, rhs: Rational) -> Rational {
        Rational::new(self.numerator * rhs.numerator, self.denominator * rhs.denominator).reduce()
    }
}

impl ops::Mul<i128> for Rational {
    type Output = Rational;

    fn mul(self, rhs: i128) -> Rational {
        Rational::new(self.numerator * rhs, self.denominator).reduce()
    }
}

impl ops::Mul<Rational> for i128 {
    type Output = Rational;

    fn mul(self, rhs: Rational) -> Rational {
        Rational::new(self * rhs.numerator, rhs.denominator).reduce()
    }
}

impl ops::Div<Rational> for Rational {
    type Output = Rational;

    fn div(self, rhs: Rational) -> Rational {
        self * rhs.inverse()
    }
}

impl ops::Div<i128> for Rational {
    type Output = Rational;

    fn div(self, rhs: i128) -> Rational {
        let rhs_inverse = Rational::new(1, rhs);
        self * rhs_inverse
    }
}

impl ops::Div<Rational> for i128 {
    type Output = Rational;

    fn div(self, rhs: Rational) -> Rational {
        self * rhs.inverse()
    }
}

#[derive(Debug, PartialEq, Clone, Copy)]
pub struct GaussianRational {
    real: Rational,
    imaginary: Rational,
}

impl GaussianRational {
    pub fn new(real: Rational, imaginary: Rational) -> Self {
        Self {
            real,
            imaginary,
        }
    }

    pub fn conjugate(&self) -> Self {
        GaussianRational::new(self.real, -1 * self.imaginary)
    }
}

impl ops::Add<GaussianRational> for GaussianRational {
    type Output = GaussianRational;

    fn add(self, rhs: GaussianRational) -> GaussianRational {
        GaussianRational::new(self.real + rhs.real, self.imaginary + rhs.imaginary)
    }
}

impl ops::Sub<GaussianRational> for GaussianRational {
    type Output = GaussianRational;

    fn sub(self, rhs: GaussianRational) -> GaussianRational {
        GaussianRational::new(self.real - rhs.real, self.imaginary - rhs.imaginary)
    }
}

impl ops::Mul<GaussianRational> for GaussianRational {
    type Output = GaussianRational;

    fn mul(self, rhs: GaussianRational) -> GaussianRational {
        GaussianRational::new(self.real * rhs.real - self.imaginary * rhs.imaginary, self.real * rhs.imaginary + self.imaginary * rhs.real)
    }
}

impl ops::Div<GaussianRational> for GaussianRational {
    type Output = GaussianRational;

    fn div(self, rhs: GaussianRational) -> GaussianRational {
        let cd_squared = rhs.real * rhs.real + rhs.imaginary * rhs.imaginary;
        GaussianRational::new(Rational::simplify(self.real * rhs.real + self.imaginary * rhs.imaginary, cd_squared), Rational::simplify(self.imaginary * rhs.real - self.real * rhs.imaginary, cd_squared))
    }
}