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Common Lisp bindings for libprimesieve
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Common Lisp bindings for the primesieve C++ library.

Generates primes orders of magnitude faster than any pure Lisp code!


  • Get an array of primes
  • Iterate over primes using little memory
  • Find the nth prime
  • Count/print primes and prime k-tuplets
  • Multi-threaded for counting primes and finding the nth prime

Usage examples

(defpackage :cl-ps-test (:use :cl :cl-primesieve))
(in-package :cl-ps-test)

;; count/print primes
(count-primes 1 100)
(print-primes 1 100)
(count-twins 1 100)
(print-twins 1 100)

;; Get an array with the primes inside the interval [start, stop].
(generate-primes 1 (expt 10 9)) ; run under 1 sec

;; Get an array with the first n primes >= start(optional).
(generate-n-primes 1000)
(generate-n-primes 1000 100) ; get 1000 primes starting from 100

;; Get the 1000th prime
(nth-prime 1000)

;; Instead of generating a large array of primes and then do something
;; with the primes it is also possible to simply iterate over the primes
;; which uses less memory.
(defvar iter (make-iterator))
(init iter)        ; init it before using it
(next-prime iter)
(skipto iter 100)  ; reset the iterator to start from 100
(next-prime iter)
(prev-prime iter)
(free-iterator iter)

;; Set/Get number of threads used.
;; By default all CPU cores are used.
(set-num-threads 2)

For convenience, package cl-primesieve has nickname cl-ps.


For Debian/Ubuntu linux:

sudo apt install primesieve
cd ~/quicklisp/local-projects/
git clone

In a lisp repl:

(ql:quickload "cl-primesieve")
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