diff options
| author | marcandre <marcandre@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2015-06-09 02:45:31 +0000 |
|---|---|---|
| committer | marcandre <marcandre@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2015-06-09 02:45:31 +0000 |
| commit | 3ed18fa8173b9efc7820eba8218eed4c25747fe3 (patch) | |
| tree | 37a9326be207e9d96f56a0fe77ff2fc46099b6c7 | |
| parent | 0d3591f250bfe90805cac3c2d5bbfcadb720df37 (diff) | |
* lib/matrix.rb: Simplify and optimize EratosthenesSieve
based on patch by Ajay Kumar. [Fixes GH-921]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50800 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | lib/prime.rb | 7 |
2 files changed, 7 insertions, 5 deletions
@@ -1,3 +1,8 @@ +Tue Jun 9 11:45:00 2015 Marc-Andre Lafortune <ruby-core@marc-andre.ca> + + * lib/matrix.rb: Simplify and optimize EratosthenesSieve + based on patch by Ajay Kumar. [Fixes GH-921] + Mon Jun 8 05:09:58 2015 Koichi Sasada <ko1@atdot.net> * gc.c (obj_info): print method id for T_IMEMO/ment. diff --git a/lib/prime.rb b/lib/prime.rb index cf5141e1a6..822f0f3ac0 100644 --- a/lib/prime.rb +++ b/lib/prime.rb @@ -425,13 +425,10 @@ class Prime root = Integer(Math.sqrt(segment_max).floor) sieving_primes = @primes[1 .. -1].take_while { |prime| prime <= root } - offsets = Array.new(sieving_primes.size) do |i| - (-(segment_min + 1 + sieving_primes[i]) / 2) % sieving_primes[i] - end segment = ((segment_min + 1) .. segment_max).step(2).to_a - sieving_primes.each_with_index do |prime, index| - composite_index = offsets[index] + sieving_primes.each do |prime| + composite_index = (-(segment_min + 1 + prime) / 2) % prime while composite_index < segment.size do segment[composite_index] = nil composite_index += prime |