roots 0.0.8

Library of well known algorithms for numerical root finding.
Documentation 
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// Copyright (c) 2015, Mikhail Vorotilov
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice, this
//   list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use super::super::FloatType;
use super::Convergency;
use std::fmt::Display;
use std::fmt::LowerExp;

/// Convergency provider for debugging.
/// It will print out the error at each iteration.
pub struct DebugConvergency<F: FloatType> {
    /// Precision for both X and Y axes
    eps: F,
    /// Maximum number of iterations
    max_iter: usize,
    /// Last iteration
    iter: usize,
}

impl<F: FloatType> DebugConvergency<F> {
    pub fn new(eps: F, max_iter: usize) -> DebugConvergency<F> {
        DebugConvergency {
            eps: eps,
            max_iter: max_iter,
            iter: 0,
        }
    }

    pub fn reset(self: &mut DebugConvergency<F>) {
        self.iter = 0;
    }

    pub fn get_iter_count(self: &DebugConvergency<F>) -> usize {
        self.iter
    }
}

impl<F: FloatType + Display + LowerExp> Convergency<F> for DebugConvergency<F> {
    /// Prints the value being checked
    fn is_root_found(&mut self, y: F) -> bool {
        println!("#{} check root {:.15e}", self.iter, y);
        y.abs() < self.eps.abs()
    }
    /// Prints values being checked
    fn is_converged(&mut self, x1: F, x2: F) -> bool {
        println!("#{} check convergency {:.15e}-{:.15e}", self.iter, x1, x2);
        (x1 - x2).abs() < self.eps.abs()
    }
    /// Updates internal iteration counter
    fn is_iteration_limit_reached(&mut self, iter: usize) -> bool {
        println!("#{} check iteration limit {}", self.iter, iter);
        self.iter = iter;
        iter >= self.max_iter
    }
}