Get rid of boost::math::constants::* and M_PI in favor of std::numbers (#6916)

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/engine/map_matching/matching_confidence.hpp

@@ -2,7 +2,7 @@
 #define ENGINE_MAP_MATCHING_CONFIDENCE_HPP
 
 #include "engine/map_matching/bayes_classifier.hpp"
-
+#include <boost/assert.hpp>
 #include <cmath>
 
 namespace osrm::engine::map_matching