givp 0.5.4

GRASP-ILS-VND with Path Relinking metaheuristic for continuous black-box optimization
Documentation 
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// SPDX-FileCopyrightText: 2026 Arnaldo Mendes Pires Junior
// SPDX-License-Identifier: MIT

use rand::Rng;
use rand_chacha::ChaCha8Rng;
use std::time::Instant;

/// Get the integer split index: defaults to num_vars / 2.
pub(crate) fn get_half(num_vars: usize, integer_split: Option<usize>) -> usize {
    integer_split.unwrap_or(num_vars / 2)
}

/// Check if the deadline has passed.
pub(crate) fn expired(deadline: Option<Instant>) -> bool {
    match deadline {
        Some(d) => Instant::now() >= d,
        None => false,
    }
}

/// Safely evaluate the objective function, returning `f64::INFINITY` on panic.
pub(crate) fn safe_evaluate<F>(func: &F, candidate: &[f64]) -> f64
where
    F: Fn(&[f64]) -> f64,
{
    let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| func(candidate)));
    match result {
        Ok(v) if v.is_finite() => v,
        _ => f64::INFINITY,
    }
}

/// Create a seeded RNG, optionally from a parent.
pub(crate) fn new_rng(seed: Option<u64>) -> ChaCha8Rng {
    use rand::SeedableRng;
    match seed {
        Some(s) => ChaCha8Rng::seed_from_u64(s),
        None => ChaCha8Rng::from_os_rng(),
    }
}

/// Spawn a child RNG from a parent.
pub(crate) fn child_rng(parent: &mut ChaCha8Rng) -> ChaCha8Rng {
    use rand::SeedableRng;
    let seed: u64 = parent.random();
    ChaCha8Rng::seed_from_u64(seed)
}

/// Round integer-portion variables to the nearest integer.
pub(crate) fn normalize_integer_tail(solution: &mut [f64], half: usize) {
    for v in solution[half..].iter_mut() {
        *v = v.round();
    }
}

/// Clamp a value to bounds.
pub(crate) fn clamp(v: f64, lo: f64, hi: f64) -> f64 {
    v.max(lo).min(hi)
}