first commit
This commit is contained in:
Jose Caban
166
extern/stdcxx/4.2.1/doc/stdlibref/partial-sum.html
vendored
Normal file
166
extern/stdcxx/4.2.1/doc/stdlibref/partial-sum.html
vendored
Normal file
@@ -0,0 +1,166 @@
|
||||
<!--
|
||||
Licensed to the Apache Software Foundation (ASF) under one or more
|
||||
contributor license agreements. See the NOTICE file distributed
|
||||
with this work for additional information regarding copyright
|
||||
ownership. The ASF licenses this file to you under the Apache
|
||||
License, Version 2.0 (the License); you may not use this file
|
||||
except in compliance with the License. You may obtain a copy of
|
||||
the License at
|
||||
|
||||
http://www.apache.org/licenses/LICENSE-2.0
|
||||
|
||||
Unless required by applicable law or agreed to in writing, software
|
||||
distributed under the License is distributed on an "AS IS" BASIS,
|
||||
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
|
||||
implied. See the License for the specific language governing
|
||||
permissions and limitations under the License.
|
||||
|
||||
Copyright 1999-2007 Rogue Wave Software, Inc.
|
||||
-->
|
||||
|
||||
<HTML>
|
||||
<HEAD>
|
||||
<TITLE>partial_sum()</TITLE>
|
||||
<LINK REL=StyleSheet HREF="../rw.css" TYPE="text/css" TITLE="Apache stdcxx Stylesheet"></HEAD>
|
||||
<BODY BGCOLOR=#FFFFFF>
|
||||
<A HREF="partial-sort-copy.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="partition.html"><IMG SRC="images/bnext.gif" WIDTH=25 HEIGHT=21 ALT="Next file" BORDER=O></A><DIV CLASS="DOCUMENTNAME"><B>Apache C++ Standard Library Reference Guide</B></DIV>
|
||||
<H2>partial_sum()</H2>
|
||||
<P><B>Library:</B> <A HREF="2-10.html">Numerics</A></P>
|
||||
|
||||
<PRE><HR><B><I>Function</I></B><HR></PRE>
|
||||
|
||||
<UL>
|
||||
<LI><A HREF="#sec1">Local Index</A></LI>
|
||||
<LI><A HREF="#sec2">Summary</A></LI>
|
||||
<LI><A HREF="#sec3">Synopsis</A></LI>
|
||||
<LI><A HREF="#sec4">Description</A></LI>
|
||||
<LI><A HREF="#sec5">Complexity</A></LI>
|
||||
<LI><A HREF="#sec6">Example</A></LI>
|
||||
<LI><A HREF="#sec7">See Also</A></LI>
|
||||
<LI><A HREF="#sec8">Standards Conformance</A></LI>
|
||||
</UL>
|
||||
<A NAME="sec1"><H3>Local Index</H3></A>
|
||||
No Entries
|
||||
<A NAME="sec2"><H3>Summary</H3></A>
|
||||
<P>Generalized numeric operation that calculates successive partial sums of a range of values</P>
|
||||
<A NAME="sec3"><H3>Synopsis</H3></A>
|
||||
|
||||
<PRE>#include <numeric>
|
||||
|
||||
namespace std {
|
||||
template <class InputIterator, class OutputIterator>
|
||||
OutputIterator partial_sum(InputIterator start,
|
||||
InputIterator finish,
|
||||
OutputIterator result);
|
||||
|
||||
template <class InputIterator,
|
||||
class OutputIterator,
|
||||
class BinaryOperation>
|
||||
OutputIterator partial_sum(InputIterator start,
|
||||
InputIterator finish,
|
||||
OutputIterator result,
|
||||
BinaryOperation binary_op);
|
||||
}
|
||||
</PRE>
|
||||
<A NAME="sec4"><H3>Description</H3></A>
|
||||
<P>The <SAMP>partial_sum()</SAMP> algorithm creates a new sequence in which every element is formed by adding all the values of the previous elements, or, in the second form of the algorithm, by applying the operation <SAMP>binary_op</SAMP> successively on every previous element. That is, <SAMP>partial_sum()</SAMP> assigns to every iterator <SAMP>i</SAMP> in the range <SAMP>[result, result + (finish - start))</SAMP> a value equal to:</P>
|
||||
|
||||
<UL><PRE>((...(*start + *(start + 1)) + ... ) +
|
||||
*(start + (i - result)))
|
||||
</PRE></UL>
|
||||
<P> or, in the second version of the algorithm:</P>
|
||||
|
||||
<UL><PRE>binary_op(binary_op(..., binary_op (*start,
|
||||
*(start + 1)),...),*(start + (i - result)))
|
||||
</PRE></UL>
|
||||
<P>For instance, applying <SAMP>partial_sum()</SAMP> to (1,2,3,4,) yields (1,3,6,10).</P>
|
||||
<P>The <SAMP>partial_sum()</SAMP> algorithm returns <SAMP>result</SAMP> <SAMP>+ (finish - start)</SAMP>.</P>
|
||||
<P>If <SAMP>result</SAMP> is equal to <SAMP>start</SAMP>, the elements of the new sequence successively replace the elements in the original sequence, effectively turning <SAMP>partial_sum()</SAMP> into an inplace transformation. </P>
|
||||
<A NAME="sec5"><H3>Complexity</H3></A>
|
||||
<P>Exactly <SAMP>(finish - start) - 1</SAMP> applications of the default <SAMP>+</SAMP> operator or <SAMP>binary_op</SAMP> are performed.</P>
|
||||
<A NAME="sec6"><H3>Example</H3></A>
|
||||
|
||||
<UL><PRE>//
|
||||
// partsum.cpp
|
||||
//
|
||||
|
||||
#include <algorithm> // for copy
|
||||
#include <functional> // for multiplies
|
||||
#include <iostream> // for cout, endl
|
||||
#include <iterator> // for ostream_iterator
|
||||
#include <numeric> // for partial_sum
|
||||
#include <vector> // for vector
|
||||
|
||||
|
||||
|
||||
int main ()
|
||||
{
|
||||
typedef std::vector<int, std::allocator<int> > Vector;
|
||||
typedef std::ostream_iterator<int, char,
|
||||
std::char_traits<char> >
|
||||
Iter;
|
||||
|
||||
// Initialize a vector using an array of integers.
|
||||
const Vector::value_type a[] = { 1, 2, 3, 4, 5,
|
||||
6, 7, 8, 9, 10 };
|
||||
Vector v (a + 0, a + sizeof a / sizeof *a);
|
||||
|
||||
// Create an empty vectors to store results.
|
||||
Vector sums (Vector::size_type (10));
|
||||
Vector prods (Vector::size_type (10));
|
||||
|
||||
// Compute partial_sums and partial_products.
|
||||
std::partial_sum (v.begin (), v.end (), sums.begin ());
|
||||
std::partial_sum (v.begin (), v.end (), prods.begin (),
|
||||
std::multiplies<Vector::value_type>());
|
||||
|
||||
// Output the results.
|
||||
std::cout << "For the series: \n ";
|
||||
std::copy (v.begin (), v.end (), Iter (std::cout, " "));
|
||||
|
||||
std::cout << "\n\nThe partial sums: \n ";
|
||||
std::copy (sums.begin (), sums.end (), Iter (std::cout,
|
||||
" "));
|
||||
std::cout << " should each equal (N*N + N)/2\n\n";
|
||||
|
||||
std::cout << "The partial products: \n ";
|
||||
std::copy (prods.begin (), prods.end (), Iter (std::cout,
|
||||
" "));
|
||||
std::cout << " should each equal N!" << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
Program Output:
|
||||
</PRE></UL>
|
||||
<UL><PRE>For the series:
|
||||
1 2 3 4 5 6 7 8 9 10
|
||||
|
||||
The partial sums:
|
||||
1 3 6 10 15 21 28 36 45 55 should each equal (N*N + N)/2
|
||||
|
||||
The partial products:
|
||||
1 2 6 24 120 720 5040 40320 362880 3628800 should each
|
||||
equal N!
|
||||
</PRE></UL>
|
||||
<A NAME="sec7"><H3>See Also</H3></A>
|
||||
<P><A HREF="algorithms.html">Algorithms</A>, <A HREF="algorithm-h.html"><algorithm></A></P>
|
||||
<A NAME="sec8"><H3>Standards Conformance</H3></A>
|
||||
<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 26.4.3</I></P>
|
||||
|
||||
<BR>
|
||||
<HR>
|
||||
<A HREF="partial-sort-copy.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="partition.html"><IMG SRC="images/bnext.gif" WIDTH=20 HEIGHT=21 ALT="Next file" BORDER=O></A>
|
||||
|
||||
<!-- Google Analytics tracking code -->
|
||||
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
|
||||
</script>
|
||||
<script type="text/javascript">
|
||||
_uacct = "UA-1775151-1";
|
||||
urchinTracker();
|
||||
</script>
|
||||
<!-- end of Google Analytics tracking code -->
|
||||
|
||||
</BODY>
|
||||
</HTML>
|
||||
Reference in New Issue
Block a user