FantasyPvP
88 lines
2.1 KiB
Rust
88 lines
2.1 KiB
Rust
use alloc::format;
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use alloc::string::String;
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use crate::println;
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const PI: f64 = 3.14159265358979323846264338327950288419716939937510;
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pub fn run_func(func: String, x: f64) -> Result<f64, String> {
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match func.as_str() {
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"sqrt" => sqrt(x),
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"ln" => ln(x),
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"fact" => factorial(x),
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"sin" => sin(x),
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"cos" => cos(x),
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"tan" => tan(x),
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_ => Err(String::from(format!("unrecognised function name: {}", func))),
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}
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}
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fn sqrt(x: f64) -> Result<f64, String> {
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if x < 0.0 {
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return Err(String::from("Cannot take the square root of a negative number"));
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}
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Ok(libm::sqrt(x))
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}
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fn ln(x: f64) -> Result<f64, String> {
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if x < 0.0 {
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return Err(String::from("Cannot take the natural log of a negative number"));
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}
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Ok(libm::log(x))
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}
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fn factorial(x: f64) -> Result<f64, String> {
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if x < 0.0 {
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return Err(String::from("Cannot take the factorial of a negative number"));
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}
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let x = x as u64;
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Ok((1..=x).fold(1, |a, b| a * b) as f64)
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}
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fn cos(mut x: f64) -> Result<f64, String> {
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while x > PI {
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x -= PI;
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}
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let res = 1.0 - trig_term(x, 2) + trig_term(x, 4) - trig_term(x, 6) + trig_term(x, 8) - trig_term(x, 10);
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if res >= -1.0 && res <= 1.0 {
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Ok(res)
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} else {
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panic!("something is very wrong with the cos function : {}", res);
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}
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}
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fn sin(mut x: f64) -> Result<f64, String> {
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while x > PI {
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x -= PI;
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}
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let res = x - trig_term(x, 3) + trig_term(x, 5) - trig_term(x, 7) + trig_term(x, 9) - trig_term(x, 11);
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if res >= -1.0 && res <= 1.0 {
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Ok(res)
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} else {
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panic!("something is very wrong with the sin function: {}", res);
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}
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}
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fn tan(x: f64) -> Result<f64, String> {
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Ok(libm::tan(x))
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}
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pub fn exp(x: f64, y: f64) -> f64 {
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let mut res = 1.0;
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for _ in 0..(y as usize) {
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res *= x
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}
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res
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}
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fn trig_term(x: f64, y: usize) -> f64 {
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let mut ex = 1.0;
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for _ in 0..y {
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ex *= x;
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}
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let fact = (1..=y).fold(1, |a, b| a*b);
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ex as f64 / fact as f64
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} |