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// (C) Copyright Herve Bronnimann 2004.
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <utility>
#include <functional>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <vector>
#include <list>
#include <set>
#include <iostream>
// What's the proper BOOST_ flag for <iomanip.h> vs <ios>
#include <iomanip>
#include <boost/timer.hpp>
#include <boost/algorithm/minmax.hpp>
template <class T1, class T2>
void tie(std::pair<T1, T2> p, T1& min, T2& max)
{
min = p.first; max = p.second;
}
template <class Value>
struct less_count : std::less<Value> {
less_count(less_count<Value> const& lc) : _M_counter(lc._M_counter) {}
less_count(int& counter) : _M_counter(counter) {}
bool operator()(Value const& a, Value const& b) const {
++_M_counter;
return std::less<Value>::operator()(a,b);
}
void reset() {
_M_counter = 0;
}
private:
int& _M_counter;
};
inline int opt_min_count(int n) {
return (n==0) ? 0 : n-1;
}
inline int opt_minmax_count(int n) {
if (n < 2) return 0;
if (n == 2) return 1;
return (n%2 == 0) ? 3*(n/2)-1 : 3*(n/2)+1;
}
inline int opt_boost_minmax_count(int n) {
if (n < 2) return 0;
if (n == 2) return 1;
return (n%2 == 0) ? 3*(n/2)-2 : 3*(n/2);
}
int repeats = 10;
#define TIMER( n, cmd , cmdname ) \
t.restart(); \
for (int i=0; i<repeats; ++i) { cmd ; } \
std::cout << " " << std::setprecision(4) \
<< (double)n*repeats/t.elapsed()/1.0E6 \
<< "M items/sec " << cmdname << "\n"
#define CTIMER( n, cmd , cmdname, count, opt ) \
t.restart(); lc.reset(); \
for (int i=0; i<repeats; ++i) { cmd ; } \
std::cout << " " << std::setprecision(4) \
<< (double)n*repeats/t.elapsed()/1.0E6 \
<< "M items/sec " << cmdname \
<< " ("<< (count)/repeats << " vs " << opt << ")\n"
template <class CIterator>
void test_minmax_element(CIterator first, CIterator last, int n, char* name)
{
typedef typename std::iterator_traits<CIterator>::value_type vtype;
boost::timer t;
std::cout << " ON " << name << " WITH OPERATOR<()\n";
TIMER( n, std::min_element(first, last),
"std::min_element" << name << "");
TIMER( n, std::max_element(first, last),
"std::max_element" << name << "");
TIMER( n, boost::first_min_element(first, last),
"boost::first_min_element" << name << "");
TIMER( n, boost::last_min_element(first, last),
"boost::last_min_element" << name << " ");
TIMER( n, boost::first_max_element(first, last),
"boost::first_max_element" << name << "");
TIMER( n, boost::last_max_element(first, last),
"boost::last_max_element" << name << " ");
TIMER( n, boost::minmax_element(first, last),
"boost::minmax_element" << name << " ");
TIMER( n, boost::first_min_last_max_element(first, last),
"boost::first_min_last_max_element" << name << "");
TIMER( n, boost::last_min_first_max_element(first, last),
"boost::last_min_first_max_element" << name << "");
TIMER( n, boost::last_min_last_max_element(first, last),
"boost::last_min_last_max_element" << name << " ");
#define pred std::bind2nd( std::greater<vtype>(), vtype(10) )
TIMER( n, boost::min_element_if(first, last, pred),
"boost::min_element_if" << name << "");
TIMER( n, boost::max_element_if(first, last, pred),
"boost::max_element_if" << name << "");
TIMER( n, std::min_element(boost::make_filter_iterator(first, last, pred),
boost::make_filter_iterator(last, last, pred)),
"std::min_element_with_filter_iterator" << name << "");
TIMER( n, std::max_element(boost::make_filter_iterator(first, last, pred),
boost::make_filter_iterator(last, last, pred)),
"std::max_element_if_with_filter_iterator" << name << "");
#undef pred
int counter = 0;
less_count<vtype> lc(counter);
std::cout << " ON " << name << " WITH LESS<> AND COUNTING COMPARISONS\n";
CTIMER( n, std::min_element(first, last, lc),
"std::min_element" << name << " ",
counter, opt_min_count(n) );
CTIMER( n, std::max_element(first, last, lc),
"std::max_element" << name << " ",
counter, opt_min_count(n) );
CTIMER( n, boost::first_min_element(first, last, lc),
"boost::first_min_element" << name << "",
counter, opt_min_count(n) );
CTIMER( n, boost::last_min_element(first, last, lc),
"boost::last_max_element" << name << " ",
counter, opt_min_count(n) );
CTIMER( n, boost::first_max_element(first, last, lc),
"boost::first_min_element" << name << "",
counter, opt_min_count(n) );
CTIMER( n, boost::last_max_element(first, last, lc),
"boost::last_max_element" << name << " ",
counter, opt_min_count(n) );
CTIMER( n, boost::minmax_element(first, last, lc),
"boost::minmax_element" << name << " ",
counter, opt_minmax_count(n) );
CTIMER( n, boost::first_min_last_max_element(first, last, lc),
"boost::first_min_last_max_element" << name << "",
counter, opt_boost_minmax_count(n) );
CTIMER( n, boost::last_min_first_max_element(first, last, lc),
"boost::last_min_first_max_element" << name << "",
counter, opt_boost_minmax_count(n) );
CTIMER( n, boost::last_min_last_max_element(first, last, lc),
"boost::last_min_last_max_element" << name << " ",
counter, opt_minmax_count(n) );
}
template <class Container, class Iterator, class Value>
void test_container(Iterator first, Iterator last, int n, char* name)
{
Container c(first, last);
typename Container::iterator fit(c.begin()), lit(c.end());
test_minmax_element(fit, lit, n, name);
}
template <class Iterator>
void test_range(Iterator first, Iterator last, int n)
{
typedef typename std::iterator_traits<Iterator>::value_type Value;
// Test various containers with these values
test_container< std::vector<Value>, Iterator, Value >(first, last, n, "<vector>");
#ifndef ONLY_VECTOR
test_container< std::list<Value>, Iterator, Value >(first, last, n, "<list> ");
test_container< std::multiset<Value>, Iterator, Value >(first, last, n, "<set> ");
#endif
}
template <class Value>
void test(int n)
{
// Populate test vector with identical values
std::cout << "IDENTICAL VALUES... \n";
std::vector<Value> test_vector(n, Value(1));
typename std::vector<Value>::iterator first( test_vector.begin() );
typename std::vector<Value>::iterator last( test_vector.end() );
test_range(first, last, n);
// Populate test vector with two values
std::cout << "TWO DISTINCT VALUES...\n";
typename std::vector<Value>::iterator middle( first + n/2 );
std::fill(middle, last, Value(2));
test_range(first, last, n);
// Populate test vector with increasing values
std::cout << "INCREASING VALUES... \n";
std::fill(first, last, Value(1));
std::accumulate(first, last, Value(0));
test_range(first, last, n);
// Populate test vector with decreasing values
std::cout << "DECREASING VALUES... \n";
std::reverse(first, last);
test_range(first, last, n);
// Populate test vector with random values
std::cout << "RANDOM VALUES... \n";
std::random_shuffle(first, last);
test_range(first, last, n);
}
int
main(char argc, char** argv)
{
int n = 100;
if (argc > 1) n = atoi(argv[1]);
if (argc > 2) repeats = atoi(argv[2]);
test<int>(n);
return 0;
}
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