https://www.reddit.com/r/rust/comments/7w3v77/why_is_my_rust_code_100x_slower_than_python/

Cargo.toml

[package]
name = "bigint"
version = "0.1.0"
authors = ["Anon"]

[dependencies]
ramp = "0.3.11"
lazy_static = "1.0.0"

main.rs

#[macro_use]
extern crate lazy_static;
extern crate ramp;

use ramp::Int;
lazy_static! {
    static ref THREE: Int = Int::from(3);
    static ref P: Int = {
        Int::from_str_radix(
            "115792089237316195423570985008687907853269984665640564039457584007908834671663",
            10,
        ).unwrap()
    };
    static ref P2: Int = {
        &*P - Int::from(2)
    };
}

#[derive(PartialEq, Clone, Debug)]
struct Point {
    x: Int,
    y: Int,
}

fn point_add(p: &Point, q: &Point) -> Point {
    let lam = if p.x == q.x && p.y == q.y {
        &*THREE * &p.x.pow(2) * ((&p.y + &p.y) % &*P).pow_mod(&*P2, &*P)
    } else {
        (&q.x - &p.x).pow_mod(&*P2, &*P) * (&q.y - &p.y) % &*P
    };

    let rx = (lam.pow(2) - &p.x - &q.x) % &*P;

    let mut ry = (&lam * (&p.x - &rx) - &p.y) % &*P;
    if ry < 0 {
        ry += &*P;
    }

    Point { x: rx, y: ry }
}

fn point_mul(p: &Point, mut d: u32) -> Point {
    let mut n = p.clone();
    let mut q = None;

    for _ in 0..256 {
        let last_bit = d & 1 == 1;
        d >>= 1;

        if last_bit {
            q = Some(q.map_or_else(|| n.clone(), |q| point_add(&q, &n)));
        }
        n = point_add(&n, &n);
    }
    q.unwrap()
}

fn main() {
    let g = Point {
        x: Int::from_str_radix(
            "79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798",
            16,
        ).unwrap(),
        y: Int::from_str_radix(
            "483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8",
            16,
        ).unwrap(),
    };

    let res = point_mul(&g, 125);
    println!(" {}", res.x);
    println!(" {}", res.y);
}