general.h

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/*
 * Copyright (c) 2008, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
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 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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#ifndef GRAPH_MAPPING_UTILS_GENERAL_H
#define GRAPH_MAPPING_UTILS_GENERAL_H

#include <ros/assert.h>
#include <cstdlib>
#include <boost/foreach.hpp>
#include <map>
#include <set>
#include <stdexcept>

namespace graph_mapping_utils
{

// Check if a container contains a key
template <class Key, class Container>
bool contains (const Container& container, const Key& key)
{
  return container.find(key)!=container.end();
}


// Get value corresponding to a key in a map, while asserting if it's not there
template <class K, class V, class C, class A>
const V& keyValue (const std::map<K, V, C, A>& m, const K& key)
{
  typename std::map<K, V, C, A>::const_iterator pos = m.find(key);
  if (pos==m.end())
    throw std::out_of_range("Map did not contain key it was expected to");
  return pos->second;
}

template <class T>
std::set<T> sampleSubset (const std::set<T>& s, const int n)
{
  if (n>(int)s.size() || n < 0)
    return s;
  else {
    std::set<T> s2;
    unsigned elements_left_to_sample = s.size();
    unsigned elements_needed = n;
    BOOST_FOREACH (const T& x, s) {
      const double p = (double) elements_needed/elements_left_to_sample;
      const double q = (double)rand()/(double)RAND_MAX;
      if (q<p) {
        s2.insert(x);
        elements_needed--;
      }
      elements_left_to_sample--;      
    }
    return s2;
  }
}

} // namespace

#endif // include guard

---

graph_mapping_utils
Author(s): Bhaskara Marthi
autogenerated on Fri Jan 11 09:58:48 2013