From 01bb0b94247a4e645b8708d5e7cca33aab9eae06 Mon Sep 17 00:00:00 2001
From: Dmitri Naumov <dmitri.naumov@ufz.de>
Date: Mon, 21 Oct 2024 11:58:59 +0200
Subject: [PATCH] [MaL] Use ranges in the cubic roots code
---
MathLib/Nonlinear/CubicRoots.h | 44 +++++++++++++++-------------------
1 file changed, 19 insertions(+), 25 deletions(-)
diff --git a/MathLib/Nonlinear/CubicRoots.h b/MathLib/Nonlinear/CubicRoots.h
index be4b0474bb0..e8d36201d1a 100644
--- a/MathLib/Nonlinear/CubicRoots.h
+++ b/MathLib/Nonlinear/CubicRoots.h
@@ -11,6 +11,10 @@
#include <algorithm>
#include <limits>
+#include <range/v3/algorithm/min.hpp>
+#include <range/v3/algorithm/sort.hpp>
+#include <range/v3/range/conversion.hpp>
+#include <range/v3/view/filter.hpp>
#include <vector>
#include "BaseLib/Error.h"
@@ -34,44 +38,34 @@ public:
std::vector<double> solve()
{
// Solve using Boost's cubic_roots
- auto roots = boost::math::tools::cubic_roots<double>(a_, b_, c_, d_);
+ std::array<double, 3> const roots =
+ boost::math::tools::cubic_roots<double>(a_, b_, c_, d_);
- // Sort array
- std::sort(roots.begin(), roots.end());
+ std::vector<double> filtered_roots =
+ ranges::views::ref(roots) |
+ ranges::views::filter([](double const root)
+ { return !std::isnan(root); }) |
+ ranges::to<std::vector>();
+ ranges::sort(filtered_roots);
- std::vector<double> roots_vector;
- for (const auto& root : roots)
- {
- if (!std::isnan(root))
- {
- roots_vector.push_back(root);
- }
- }
- return roots_vector;
+ return filtered_roots;
}
// Method that returns the smallest positive real root
double smallestPositiveRealRoot()
{
- auto roots = solve();
- double min_positive_root = std::numeric_limits<double>::infinity();
+ std::vector<double> const roots = solve();
- // Find the smallest positive real root
- for (const auto& root : roots)
- {
- if (root > 0 && root < min_positive_root)
- {
- min_positive_root = root;
- }
- }
+ auto positive_roots =
+ roots | ranges::views::filter([](double root) { return root > 0; });
- // If no positive root was found, return NaN
- if (min_positive_root == std::numeric_limits<double>::infinity())
+ // If no positive root exists, return NaN
+ if (ranges::empty(positive_roots))
{
return std::numeric_limits<double>::quiet_NaN();
}
- return min_positive_root;
+ return ranges::min(positive_roots);
}
private:
--
GitLab