optimum 0.0.4

Future Framework to solve optimization problems
Documentation 
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use crate::core::{Objective, Problem, StopCriterion};

use num_traits::{One, Zero};

/// Stops as soon as a target value is reached.
#[derive(Debug, Clone)]
pub struct QualityCriterion<P: Problem> {
    target: P::Value,
    done: bool,
    current_iter: usize,
}

impl<P: Problem> QualityCriterion<P> {
    /// Creates a quality criterion based on `target`.
    pub fn new(target: P::Value) -> Self {
        Self {
            target,
            done: false,
            current_iter: 0,
        }
    }
}

impl<P: Problem> StopCriterion<P> for QualityCriterion<P> {
    fn progress(&self) -> f64 {
        if self.done {
            f64::one()
        } else {
            f64::zero()
        }
    }

    fn update(&mut self, new_value: <P as Problem>::Value) {
        self.done = match P::OBJECTIVE {
            Objective::Min => new_value <= self.target,
            Objective::Max => new_value >= self.target,
        };
        self.current_iter += 1;
    }

    fn current_iter(&self) -> usize {
        self.current_iter
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_works() {
        let mut criterion = QualityCriterion::<()>::new(0);

        assert_ne!(criterion.progress(), f64::one());

        criterion.update(0);

        assert_eq!(criterion.progress(), f64::one());
    }
}