From 0196543ffbe266455d13acd5f49ffda9ae9de312 Mon Sep 17 00:00:00 2001
From: Dmitri Naumov <github@naumov.de>
Date: Sat, 1 Oct 2016 22:52:34 +0200
Subject: [PATCH] [NL] Replace find with binary search.
This trades a copy of nodes pointers vs. O(#Elements * #Nodes/2) complexity.
---
NumLib/DOF/LocalToGlobalIndexMap.cpp | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/NumLib/DOF/LocalToGlobalIndexMap.cpp b/NumLib/DOF/LocalToGlobalIndexMap.cpp
index 6e38c48ab4c..82ec698b7ca 100644
--- a/NumLib/DOF/LocalToGlobalIndexMap.cpp
+++ b/NumLib/DOF/LocalToGlobalIndexMap.cpp
@@ -37,6 +37,9 @@ void LocalToGlobalIndexMap::findGlobalIndices(
{
_rows.resize(std::distance(first, last), _mesh_subsets.size());
+ std::vector<MeshLib::Node*> sorted_nodes{nodes};
+ std::sort(std::begin(sorted_nodes), std::end(sorted_nodes));
+
// For each element find the global indices for node/element
// components.
std::size_t elem_id = 0;
@@ -48,8 +51,8 @@ void LocalToGlobalIndexMap::findGlobalIndices(
n < (*e)->getNodes() + (*e)->getNumberOfNodes(); ++n)
{
// Check if the element's node is in the given list of nodes.
- if (std::find(std::begin(nodes), std::end(nodes), *n) ==
- std::end(nodes))
+ if (!std::binary_search(std::begin(sorted_nodes),
+ std::end(sorted_nodes), *n))
continue;
MeshLib::Location l(
mesh_id, MeshLib::MeshItemType::Node, (*n)->getID());
--
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