'Rcpp' Interface to 'sparsepp'

Provides interface to 'sparsepp' - fast, memory efficient hash map. It is derived from Google's excellent 'sparsehash' implementation. We believe 'sparsepp' provides an unparalleled combination of performance and memory usage, and will outperform your compiler's unordered_map on both counts. Only Google's 'dense_hash_map' is consistently faster, at the cost of much greater memory usage (especially when the final size of the map is not known in advance).


CRAN_Status_Badge License

Check original sparsepp repository and write-up which compares hashmap implementations.

insert-benchmark

Use sparsepp from another package

To use C++ code from sparsepp:

  1. In DESCRIPTION, add LinkingTo: sparsepp.
  2. In the C++ file, add: #include <sparsepp/spp.h>

Simple example

#include <sparsepp/spp.h>
using spp::sparse_hash_map;
sparse_hash_map<string, int> smap;

Defining custom hash function

#include <iostream>
#include <functional>
#include <string>
#include <sparsepp/spp.h>
 
using std::string;
 
struct Person 
{
    bool operator==(const Person &o) const 
    { return _first == o._first && _last == o._last}
 
    string _first;
    string _last;
};
 
namespace std
{
    // inject specialization of std::hash for Person into namespace std 
    // ---------------------------------------------------------------- 
    template<> 
    struct hash<Person>
    {
        std::size_t operator()(Person const &p) const
        {
            std::size_t seed = 0;
            spp::hash_combine(seed, p._first);
            spp::hash_combine(seed, p._last);
            return seed;
        }
    };
}
 
int main()
{
    // As we have defined a specialization of std::hash() for Person,  
    // we can now create sparse_hash_set or sparse_hash_map of Persons 
    // ---------------------------------------------------------------- 
    spp::sparse_hash_set<Person> persons = { { "John""Galt" }
                                             { "Jane""Doe" } };
    for (auto& p: persons)
        std::cout << p._first << ' ' << p._last << '\n';
}

News

2018-09-19

  • update to upstream v1.22

2018-07-25

  • updated to upstream v1.21

Reference manual

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install.packages("sparsepp")

1.22 by Dmitriy Selivanov, a year ago


https://github.com/greg7mdp/sparsepp, https://github.com/dselivanov/r-sparsepp


Report a bug at https://github.com/dselivanov/r-sparsepp/issues


Browse source code at https://github.com/cran/sparsepp


Authors: Gregory Popovitch [aut, cph] , Google Inc [aut, cph] , Dmitriy Selivanov [cre]


Documentation:   PDF Manual  


BSD_3_clause + file LICENSE license


Suggests Rcpp


Linked to by text2vec.


See at CRAN