ganesh 0.27.0

Minimization and sampling in Rust, simplified
Documentation 
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use crate::{
    traits::{CostFunction, Gradient},
    DVector, Float, PI,
};
use std::convert::Infallible;

/// The Rastrigin function, a non-convex function with a single minimum but many local minima.
///
/// ```math
/// f(\vec{x}) = 10n + \sum_{i=1}^n (x_i^2 - 10cos(2\pi x_i))
/// ```
pub struct Rastrigin {
    /// The number of dimensions of the function (must be >= 2).
    pub n: usize,
}
impl CostFunction for Rastrigin {
    fn evaluate(&self, x: &DVector<Float>, _args: &()) -> Result<Float, Infallible> {
        #[allow(clippy::suboptimal_flops)]
        Ok(10.0 * self.n as Float
            + (0..self.n)
                .map(|i| x[i].powi(2) - 10.0 * Float::cos(2.0 * PI * x[i]))
                .sum::<Float>())
    }
}
impl Gradient for Rastrigin {}