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use std::fmt; #[allow(unused_imports)] use structure::matrix::*; use structure::vector::*; use util::useful::*; #[derive(Debug, Clone)] pub struct Multinomial { coef: Vector, } impl fmt::Display for Multinomial { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { let mut result = String::new(); let l = self.coef.len(); if l == 1 { let value = self.coef[0]; let target = choose_shorter_string(format!("{}x_0", value), format!("{:.4}x_0", value)); return write!(f, "{}", target); } let first_value = self.coef[0]; result.push_str(&choose_shorter_string( format!("{}x_0", first_value), format!("{:.4}x_0", first_value), )); for i in 1..l { let value = self.coef[i]; if value > 0. { let target = choose_shorter_string( format!(" + {}x_{}", value, i), format!(" + {:.4}x_{}", value, i), ); result.push_str(&target); } else if value < 0. { let target = choose_shorter_string( format!(" - {}x_{}", value, i), format!(" - {:.4}x_{}", value, i), ); result.push_str(&target); } } write!(f, "{}", result) } } impl Multinomial { pub fn new(coef: Vector) -> Self { Self { coef } } pub fn eval(&self, values: &Vector) -> f64 { self.coef.dot(values) } }