Get rid of boost::math::constants::* in favor of std::numbers

include/engine/map_matching/bayes_classifier.hpp

@@ -6,7 +6,7 @@
 #include <utility>
 #include <vector>
 
-#include <boost/math/constants/constants.hpp>
+#include <numbers>
 
 namespace osrm::engine::map_matching
 {
@@ -21,10 +21,8 @@ struct NormalDistribution
     // FIXME implement log-probability version since it's faster
     double Density(const double val) const
     {
-        using namespace boost::math::constants;
-
         const double x = val - mean;
-        return 1.0 / (std::sqrt(two_pi<double>()) * standard_deviation) *
+        return 1.0 / (std::sqrt(2 * std::numbers::pi) * standard_deviation) *
                std::exp(-x * x / (standard_deviation * standard_deviation));
     }
 

include/engine/map_matching/hidden_markov_model.hpp

@@ -4,7 +4,7 @@
 #include "util/integer_range.hpp"
 
 #include <boost/assert.hpp>
-#include <boost/math/constants/constants.hpp>
+#include <numbers>
 
 #include <cmath>
 
@@ -14,7 +14,7 @@
 namespace osrm::engine::map_matching
 {
 
-static const double log_2_pi = std::log(2. * boost::math::constants::pi<double>());
+static const double log_2_pi = std::log(2. * std::numbers::pi);
 static const double IMPOSSIBLE_LOG_PROB = -std::numeric_limits<double>::infinity();
 static const double MINIMAL_LOG_PROB = std::numeric_limits<double>::lowest();
 static const std::size_t INVALID_STATE = std::numeric_limits<std::size_t>::max();

include/util/coordinate_calculation.hpp

@@ -3,7 +3,7 @@
 
 #include "util/coordinate.hpp"
 
-#include <boost/math/constants/constants.hpp>
+#include <numbers>
 
 #include <algorithm>
 #include <cmath>
@@ -23,17 +23,9 @@ const constexpr double RAD_TO_DEGREE = 1. / DEGREE_TO_RAD;
 // The IUGG value for the equatorial radius is 6378.137 km (3963.19 miles)
 const constexpr long double EARTH_RADIUS = 6372797.560856;
 
-inline double degToRad(const double degree)
-{
-    using namespace boost::math::constants;
-    return degree * (pi<double>() / 180.0);
-}
+inline double degToRad(const double degree) { return degree * (std::numbers::pi / 180.0); }
 
-inline double radToDeg(const double radian)
-{
-    using namespace boost::math::constants;
-    return radian * (180.0 * (1. / pi<double>()));
-}
+inline double radToDeg(const double radian) { return radian * (180.0 * (1. / std::numbers::pi)); }
 } // namespace detail
 
 const constexpr static double METERS_PER_DEGREE_LAT = 110567.0;

include/util/trigonometry_table.hpp

@@ -6,7 +6,7 @@
 
 #include <limits>
 
-#include <boost/math/constants/constants.hpp>
+#include <numbers>
 
 namespace osrm::util
 {
@@ -359,22 +359,22 @@ constexpr unsigned short atan_table[4096] = {
 #ifdef _MSC_VER // TODO: remove as soon as boost allows C++14 features with Visual Studio
 const constexpr double SCALING_FACTOR = 4. / M_PI * 0xFFFF;
 #else
-const constexpr double SCALING_FACTOR = 4. / boost::math::constants::pi<double>() * 0xFFFF;
+const constexpr double SCALING_FACTOR = 4. / std::numbers::pi * 0xFFFF;
 #endif
 
 inline double atan2_lookup(double y, double x)
 {
-    using namespace boost::math::constants;
+    static constexpr auto half_pi = std::numbers::pi * 0.5;
 
     if (std::abs(x) < std::numeric_limits<double>::epsilon())
     {
         if (y >= 0.)
         {
-            return half_pi<double>();
+            return half_pi;
         }
         else
         {
-            return -half_pi<double>();
+            return -half_pi;
         }
     }
 
@@ -405,25 +405,25 @@ inline double atan2_lookup(double y, double x)
     case 0:
         break;
     case 1:
-        angle = pi<double>() - angle;
+        angle = std::numbers::pi - angle;
         break;
     case 2:
         angle = -angle;
         break;
     case 3:
-        angle = -pi<double>() + angle;
+        angle = -std::numbers::pi + angle;
         break;
     case 4:
-        angle = half_pi<double>() - angle;
+        angle = half_pi - angle;
         break;
     case 5:
-        angle = half_pi<double>() + angle;
+        angle = half_pi + angle;
         break;
     case 6:
-        angle = -half_pi<double>() + angle;
+        angle = -half_pi + angle;
         break;
     case 7:
-        angle = -half_pi<double>() - angle;
+        angle = -half_pi - angle;
         break;
     }
     return angle;

include/util/web_mercator.hpp

@@ -3,7 +3,7 @@
 
 #include "util/coordinate.hpp"
 
-#include <boost/math/constants/constants.hpp>
+#include <numbers>
 
 namespace osrm::util::web_mercator
 {
@@ -14,7 +14,7 @@ const constexpr double RAD_TO_DEGREE = 1. / DEGREE_TO_RAD;
 // radius used by WGS84
 const constexpr double EARTH_RADIUS_WGS84 = 6378137.0;
 // earth circumference devided by 2
-const constexpr double MAXEXTENT = EARTH_RADIUS_WGS84 * boost::math::constants::pi<double>();
+const constexpr double MAXEXTENT = EARTH_RADIUS_WGS84 * std::numbers::pi;
 // ^ math functions are not constexpr since they have side-effects (setting errno) :(
 const constexpr double EPSG3857_MAX_LATITUDE = 85.051128779806592378; // 90(4*atan(exp(pi))/pi-1)
 const constexpr double MAX_LONGITUDE = 180.0;

src/util/coordinate_calculation.cpp

@@ -146,7 +146,6 @@ double bearing(const Coordinate coordinate_1, const Coordinate coordinate_2)
 
 double computeAngle(const Coordinate first, const Coordinate second, const Coordinate third)
 {
-    using namespace boost::math::constants;
     using namespace coordinate_calculation;
 
     if (first == second || second == third)
@@ -163,7 +162,7 @@ double computeAngle(const Coordinate first, const Coordinate second, const Coord
     const double v2y =
         web_mercator::latToY(toFloating(third.lat)) - web_mercator::latToY(toFloating(second.lat));
 
-    double angle = (atan2_lookup(v2y, v2x) - atan2_lookup(v1y, v1x)) * 180. / pi<double>();
+    double angle = (atan2_lookup(v2y, v2x) - atan2_lookup(v1y, v1x)) * 180. / std::numbers::pi;
 
     while (angle < 0.)
     {