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// Copyright 2018 Stefan Kroboth // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or // http://opensource.org/licenses/MIT>, at your option. This file may not be // copied, modified, or distributed except according to those terms. //! # Booth test function //! //! Defined as //! //! `f(x_1, x_2) = (x_1 + 2*x_2 - 7)^2 + (2*x_1 + x_2 - 5)^2 //! //! where `x_i \in [-10, 10]`. //! //! The global minimum is at `f(x_1, x_2) = f(1, 3) = 0`. use num::{Float, FromPrimitive}; /// Booth test function /// /// Defined as /// /// `f(x_1, x_2) = (x_1 + 2*x_2 - 7)^2 + (2*x_1 + x_2 - 5)^2 /// /// where `x_i \in [-10, 10]`. /// /// The global minimum is at `f(x_1, x_2) = f(1, 3) = 0`. pub fn booth<T: Float + FromPrimitive>(param: &[T]) -> T { assert!(param.len() == 2); let (x1, x2) = (param[0], param[1]); (x1 + T::from_f64(2.0).unwrap() * x2 - T::from_f64(7.0).unwrap()).powi(2) + (T::from_f64(2.0).unwrap() * x1 + x2 - T::from_f64(5.0).unwrap()).powi(2) } mod tests { #[test] fn test_booth_optimum() { assert!((::booth(&[1_f32, 3_f32])).abs() < ::std::f32::EPSILON); assert!((::booth(&[1_f64, 3_f64])).abs() < ::std::f64::EPSILON); } #[test] #[should_panic] fn test_booth_param_length() { ::booth(&[0.0_f32, -1.0_f32, 0.1_f32]); } }