From 21ecb8c209e286f3f731a9a9f5e328b1ec4d9c54 Mon Sep 17 00:00:00 2001
From: Siarhei Fedartsou <siarhei.fedartsou@gmail.com>
Date: Fri, 10 May 2024 20:30:14 +0200
Subject: [PATCH] Optimise path distance calculation in MLD map matching

---
 .../routing_algorithms/routing_base_mld.hpp   | 32 +++++++++++++++++--
 src/benchmarks/match.cpp                      |  2 ++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/include/engine/routing_algorithms/routing_base_mld.hpp b/include/engine/routing_algorithms/routing_base_mld.hpp
index c577c3be3..b680867ee 100644
--- a/include/engine/routing_algorithms/routing_base_mld.hpp
+++ b/include/engine/routing_algorithms/routing_base_mld.hpp
@@ -650,11 +650,37 @@ double getNetworkDistance(SearchEngineData<Algorithm> &engine_working_data,
         return std::numeric_limits<double>::max();
     }
 
-    std::vector<PathData> unpacked_path;
 
-    annotatePath(facade, endpoints, unpacked_nodes, unpacked_edges, unpacked_path);
 
-    return getPathDistance(facade, unpacked_path, source_phantom, target_phantom);
+    EdgeDistance distance = {0.0};
+
+    if (source_phantom.forward_segment_id.id == unpacked_nodes[0])
+    {
+        BOOST_ASSERT(source_phantom.forward_segment_id.enabled);
+        distance = EdgeDistance{0} - source_phantom.GetForwardDistance();
+    }
+    else if (source_phantom.reverse_segment_id.id == unpacked_nodes[0])
+    {
+        BOOST_ASSERT(source_phantom.reverse_segment_id.enabled);
+        distance = EdgeDistance{0} - source_phantom.GetReverseDistance();
+    }
+    
+    for (size_t index = 0; index < unpacked_nodes.size() - 1; ++index) {
+        distance += facade.GetNodeDistance(unpacked_nodes[index]);
+    }
+    
+    if (target_phantom.forward_segment_id.id == unpacked_nodes.back())
+    {
+        BOOST_ASSERT(target_phantom.forward_segment_id.enabled);
+        distance += target_phantom.GetForwardDistance();
+    }
+    else if (target_phantom.reverse_segment_id.id == unpacked_nodes.back())
+    {
+        BOOST_ASSERT(target_phantom.reverse_segment_id.enabled);
+        distance += target_phantom.GetReverseDistance();
+    }
+
+    return static_cast<double>(static_cast<float>(distance));
 }
 
 } // namespace osrm::engine::routing_algorithms::mld
diff --git a/src/benchmarks/match.cpp b/src/benchmarks/match.cpp
index 932820e88..8bad6ea95 100644
--- a/src/benchmarks/match.cpp
+++ b/src/benchmarks/match.cpp
@@ -1,3 +1,4 @@
+#include "engine/engine_config.hpp"
 #include "util/timing_util.hpp"
 
 #include "osrm/match_parameters.hpp"
@@ -32,6 +33,7 @@ try
     // Configure based on a .osrm base path, and no datasets in shared mem from osrm-datastore
     EngineConfig config;
     config.storage_config = {argv[1]};
+    config.algorithm = (argc > 2 && std::string{argv[2]} == "mld") ? EngineConfig::Algorithm::MLD : EngineConfig::Algorithm::CH;
     config.use_shared_memory = false;
 
     // Routing machine with several services (such as Route, Table, Nearest, Trip, Match)