From 0ab2fe85eb6e0cc79c4e5c260fc92d296cc2bd50 Mon Sep 17 00:00:00 2001
From: Kyle Lutz <kyle.r.lutz@gmail.com>
Date: Sat, 27 Apr 2013 10:30:26 -0400
Subject: [PATCH] Don't auto-initialize values in vector

This changes the vector class to not auto-initialize values
when it is created or resized. This improves performance by
eliminating a call to fill(). If needed, user code can call
fill() explicitly on the newly allocated values.
---
 doc/reference/container/vector.xml         | 10 ++++++++++
 include/boost/compute/container/vector.hpp | 14 +-------------
 2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/doc/reference/container/vector.xml b/doc/reference/container/vector.xml
index 9c1f2c54..75ed9290 100644
--- a/doc/reference/container/vector.xml
+++ b/doc/reference/container/vector.xml
@@ -16,6 +16,16 @@
             <purpose>allocator type</purpose>
           </template-type-parameter>
         </template>
+
+        <description>
+          <para>
+            Note: Unlike <code>std::vector</code>,
+            <code>boost::compute::vector</code> does not initialize values
+            when the created or resized. If initialization is needed you must
+            explicitly call <functionname>fill()</functionname> on the newly
+            allocated values.
+          </para>
+        </description>
       </class>
     </namespace>
   </namespace>
diff --git a/include/boost/compute/container/vector.hpp b/include/boost/compute/container/vector.hpp
index 53bcc8a2..baddb342 100644
--- a/include/boost/compute/container/vector.hpp
+++ b/include/boost/compute/container/vector.hpp
@@ -30,7 +30,6 @@
 #include <boost/compute/context.hpp>
 #include <boost/compute/command_queue.hpp>
 #include <boost/compute/algorithm/copy.hpp>
-#include <boost/compute/algorithm/fill.hpp>
 #include <boost/compute/algorithm/fill_n.hpp>
 #include <boost/compute/container/allocator.hpp>
 #include <boost/compute/iterator/buffer_iterator.hpp>
@@ -242,17 +241,9 @@ public:
         return m_allocator.max_size();
     }
 
-    void resize(size_type size, T value = T())
+    void resize(size_type size)
     {
         if(size < capacity()){
-            if(size < m_size){
-                ::boost::compute::fill(
-                    begin() + static_cast<difference_type>(size),
-                    begin() + static_cast<difference_type>(m_size),
-                    value
-                );
-            }
-
             m_size = size;
         }
         else {
@@ -272,9 +263,6 @@ public:
             // copy old values to the new buffer
             ::boost::compute::copy(m_data, m_data + m_size, new_data, queue);
 
-            // fill the rest of the new vector with value
-            ::boost::compute::fill(new_data + m_size, new_data + size, value, queue);
-
             // free old memory
             m_allocator.deallocate(m_data, m_size);