primesieve Namespace Reference

Contains primesieve's C++ functions and classes. More...

Classes
class	iterator
	primesieve::iterator allows to easily iterate over primes both forwards and backwards. More...
class	primesieve_error
	primesieve throws a primesieve_error exception if an error occurs e.g. More...

Functions
template<typename T >
void	generate_primes (uint64_t stop, std::vector< T > *primes)
	Store the primes <= stop in the primes vector.
template<typename T >
void	generate_primes (uint64_t start, uint64_t stop, std::vector< T > *primes)
	Store the primes within the interval [start, stop] in the primes vector.
template<typename T >
void	generate_n_primes (uint64_t n, std::vector< T > *primes)
	Store the first n primes in the primes vector.
template<typename T >
void	generate_n_primes (uint64_t n, uint64_t start, std::vector< T > *primes)
	Store the first n primes >= start in the primes vector.
uint64_t	nth_prime (int64_t n, uint64_t start=0)
	Find the nth prime. More...
uint64_t	count_primes (uint64_t start, uint64_t stop)
	Count the primes within the interval [start, stop]. More...
uint64_t	count_twins (uint64_t start, uint64_t stop)
	Count the twin primes within the interval [start, stop]. More...
uint64_t	count_triplets (uint64_t start, uint64_t stop)
	Count the prime triplets within the interval [start, stop]. More...
uint64_t	count_quadruplets (uint64_t start, uint64_t stop)
	Count the prime quadruplets within the interval [start, stop]. More...
uint64_t	count_quintuplets (uint64_t start, uint64_t stop)
	Count the prime quintuplets within the interval [start, stop]. More...
uint64_t	count_sextuplets (uint64_t start, uint64_t stop)
	Count the prime sextuplets within the interval [start, stop]. More...
void	print_primes (uint64_t start, uint64_t stop)
	Print the primes within the interval [start, stop] to the standard output.
void	print_twins (uint64_t start, uint64_t stop)
	Print the twin primes within the interval [start, stop] to the standard output.
void	print_triplets (uint64_t start, uint64_t stop)
	Print the prime triplets within the interval [start, stop] to the standard output.
void	print_quadruplets (uint64_t start, uint64_t stop)
	Print the prime quadruplets within the interval [start, stop] to the standard output.
void	print_quintuplets (uint64_t start, uint64_t stop)
	Print the prime quintuplets within the interval [start, stop] to the standard output.
void	print_sextuplets (uint64_t start, uint64_t stop)
	Print the prime sextuplets within the interval [start, stop] to the standard output.
uint64_t	get_max_stop ()
	Returns the largest valid stop number for primesieve. More...
int	get_sieve_size ()
	Get the current set sieve size in KiB.
int	get_num_threads ()
	Get the current set number of threads.
void	set_sieve_size (int sieve_size)
	Set the sieve size in KiB (kibibyte). More...
void	set_num_threads (int num_threads)
	Set the number of threads for use in primesieve::count_*() and primesieve::nth_prime(). More...
std::string	primesieve_version ()
	Get the primesieve version number, in the form “i.j”.

Detailed Description

Contains primesieve's C++ functions and classes.

Function Documentation

count_primes()

uint64_t primesieve::count_primes	(	uint64_t	start,
		uint64_t	stop
	)

Count the primes within the interval [start, stop].

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

Note that each call to count_primes() incurs an initialization overhead of O(sqrt(stop)) even if the interval [start, stop] is tiny. Hence if you have written an algorithm that makes many calls to count_primes() it may be preferable to use a primesieve::iterator which needs to be initialized only once.

Examples

count_primes.cpp.

count_quadruplets()

uint64_t primesieve::count_quadruplets	(	uint64_t	start,
		uint64_t	stop
	)

Count the prime quadruplets within the interval [start, stop].

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

count_quintuplets()

uint64_t primesieve::count_quintuplets	(	uint64_t	start,
		uint64_t	stop
	)

Count the prime quintuplets within the interval [start, stop].

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

count_sextuplets()

uint64_t primesieve::count_sextuplets	(	uint64_t	start,
		uint64_t	stop
	)

Count the prime sextuplets within the interval [start, stop].

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

count_triplets()

uint64_t primesieve::count_triplets	(	uint64_t	start,
		uint64_t	stop
	)

Count the prime triplets within the interval [start, stop].

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

count_twins()

uint64_t primesieve::count_twins	(	uint64_t	start,
		uint64_t	stop
	)

Count the twin primes within the interval [start, stop].

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

get_max_stop()

uint64_t primesieve::get_max_stop

(

)

Returns the largest valid stop number for primesieve.

Returns

2^64-1 (UINT64_MAX).

nth_prime()

uint64_t primesieve::nth_prime	(	int64_t	n,
		uint64_t	start = 0
	)

Find the nth prime.

By default all CPU cores are used, use primesieve::set_num_threads(int threads) to change the number of threads.

Note that each call to nth_prime(n, start) incurs an initialization overhead of O(sqrt(start)) even if n is tiny. Hence it is not a good idea to use nth_prime() repeatedly in a loop to get the next (or previous) prime. For this use case it is better to use a primesieve::iterator which needs to be initialized only once.

Parameters

n	if n = 0 finds the 1st prime >= start, if n > 0 finds the nth prime > start, if n < 0 finds the nth prime < start (backwards).

Examples

nth_prime.cpp.

set_num_threads()

void primesieve::set_num_threads

(

int

num_threads

)

Set the number of threads for use in primesieve::count_*() and primesieve::nth_prime().

By default all CPU cores are used.

set_sieve_size()

void primesieve::set_sieve_size

(

int

sieve_size

)

Set the sieve size in KiB (kibibyte).

The best sieving performance is achieved with a sieve size of your CPU's L1 or L2 cache size (per core).

Precondition

sieve_size >= 8 && <= 4096.