From f86b5baf8db3578202505e97a6f0aa6de5737354 Mon Sep 17 00:00:00 2001
From: Samuel Tardieu <sam@rfc1149.net>
Date: Fri, 26 Dec 2008 20:58:46 +0100
Subject: [PATCH] Use math.primes.erato instead of a list of first prime
numbers
---
extra/math/primes/primes-docs.factor | 2 +-
extra/math/primes/primes-tests.factor | 4 +++
extra/math/primes/primes.factor | 45 +++++++++++----------------
3 files changed, 24 insertions(+), 27 deletions(-)
diff --git a/extra/math/primes/primes-docs.factor b/extra/math/primes/primes-docs.factor
index 1077659d5e..516b081624 100644
--- a/extra/math/primes/primes-docs.factor
+++ b/extra/math/primes/primes-docs.factor
@@ -4,7 +4,7 @@ IN: math.primes
{ next-prime prime? } related-words
HELP: next-prime
-{ $values { "n" "a positive integer" } { "p" "a prime number" } }
+{ $values { "n" "an integer not smaller than 2" } { "p" "a prime number" } }
{ $description "Return the next prime number greater than " { $snippet "n" } "." } ;
HELP: prime?
diff --git a/extra/math/primes/primes-tests.factor b/extra/math/primes/primes-tests.factor
index 186acc9b11..b0b25285c0 100644
--- a/extra/math/primes/primes-tests.factor
+++ b/extra/math/primes/primes-tests.factor
@@ -8,3 +8,7 @@ USING: arrays math.primes tools.test lists.lazy ;
{ { 999983 1000003 } } [ 2 999982 lprimes-from ltake list>array ] unit-test
{ { 2 3 5 7 } } [ 10 primes-upto >array ] unit-test
{ { 999983 1000003 } } [ 999982 1000010 primes-between >array ] unit-test
+
+{ { 4999963 4999999 5000011 5000077 5000081 } }
+[ 4999962 5000082 primes-between >array ]
+unit-test
diff --git a/extra/math/primes/primes.factor b/extra/math/primes/primes.factor
index d93910ec02..c8f398863f 100644
--- a/extra/math/primes/primes.factor
+++ b/extra/math/primes/primes.factor
@@ -1,46 +1,39 @@
! Copyright (C) 2007 Samuel Tardieu.
! See http://factorcode.org/license.txt for BSD license.
USING: binary-search combinators kernel lists.lazy math math.functions
- math.miller-rabin math.primes.list sequences ;
+math.miller-rabin math.primes.erato math.ranges sequences ;
IN: math.primes
<PRIVATE
-: find-prime-miller-rabin ( n -- p )
- [ dup miller-rabin ] [ 2 + ] [ ] until ; foldable
+: look-in-bitmap ( n -- ? ) >index 4999999 sieve nth ;
+
+: really-prime? ( n -- ? )
+ dup 5000000 < [ look-in-bitmap ] [ miller-rabin ] if ; foldable
PRIVATE>
-: next-prime ( n -- p )
- dup 999983 < [
- primes-under-million [ natural-search drop 1+ ] keep nth
- ] [
- next-odd find-prime-miller-rabin
- ] if ; foldable
-
: prime? ( n -- ? )
- dup 1000000 < [
- dup primes-under-million natural-search nip =
- ] [
- miller-rabin
- ] if ; foldable
+ {
+ { [ dup 2 < ] [ drop f ] }
+ { [ dup even? ] [ 2 = ] }
+ [ really-prime? ]
+ } cond ; foldable
-: lprimes ( -- list )
- 0 primes-under-million seq>list
- 1000003 [ 2 + find-prime-miller-rabin ] lfrom-by
- lappend ;
+: next-prime ( n -- p )
+ next-odd [ dup really-prime? ] [ 2 + ] [ ] until ; foldable
+
+: lprimes ( -- list ) 2 [ next-prime ] lfrom-by ;
: lprimes-from ( n -- list )
dup 3 < [ drop lprimes ] [ 1- next-prime [ next-prime ] lfrom-by ] if ;
: primes-upto ( n -- seq )
- {
- { [ dup 2 < ] [ drop { } ] }
- { [ dup 1000003 < ] [
- primes-under-million [ natural-search drop 1+ 0 swap ] keep <slice>
- ] }
- [ lprimes swap [ <= ] curry lwhile list>array ]
- } cond ; foldable
+ dup 2 < [
+ drop V{ }
+ ] [
+ 3 swap 2 <range> [ prime? ] filter 2 prefix
+ ] if ; foldable
: primes-between ( low high -- seq )
primes-upto [ 1- next-prime ] dip