From: David Wells <wellsd2@rpi.edu>
Date: Sat, 1 Apr 2017 16:53:46 +0000 (-0400)
Subject: Resize a vector instead of repeatedly calling push_back.
X-Git-Tag: v9.0.0-rc1~1753^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a6c42fd7bf9745d1bdbcbd058b235ab0eaf05ffd;p=dealii.git

Resize a vector instead of repeatedly calling push_back.

std::vector<double>(0) creates an empty vector, so we can save some time by just
resizing the vector of vectors instead.
---

diff --git a/source/numerics/point_value_history.cc b/source/numerics/point_value_history.cc
index fbd5d18d1e..fe1ac2fb8a 100644
--- a/source/numerics/point_value_history.cc
+++ b/source/numerics/point_value_history.cc
@@ -309,10 +309,7 @@ void PointValueHistory<dim>
       // entry
       const ComponentMask &current_mask = (component_mask.find (data_store_begin->first))->second;
       unsigned int n_stored = current_mask.n_selected_components();
-      for (unsigned int component = 0; component < n_stored; component++)
-        {
-          data_store_begin->second.push_back (std::vector<double> (0));
-        }
+      data_store_begin->second.resize(data_store_begin->second.size() + n_stored);
     }
 }
 
@@ -429,10 +426,7 @@ void PointValueHistory<dim>
           // entry
           const ComponentMask current_mask = (component_mask.find (data_store_begin->first))->second;
           unsigned int n_stored = current_mask.n_selected_components();
-          for (unsigned int component = 0; component < n_stored; component++)
-            {
-              data_store_begin->second.push_back (std::vector<double> (0));
-            }
+          data_store_begin->second.resize(data_store_begin->second.size() + n_stored);
         }
     }
 }