Miller Rabin algorithm can be used to test primality for integers smaller than a max value "MaxMR" (~3e24)
It can be much faster than previous implementation: ~100x faster for numbers with 13 digits, at least 5 orders of magnitude for even larger numbers (previous implementation is so slow that it requires more patience than I have for more precise estimate).
Miller Rabin test becomes faster than previous implementation at somewhere in the range 1e5-1e6. It seems that the range 62000..66000 is where Miller Rabin starts being always faster, so I picked 0xffff arbitrarily; before that, or above "MaxMR", the previous implementation remains.
I compared the `faster_prime` gem too. It is slower than previous implementation up to ~1e4. After that it becomes faster and faster compared to previous implementation, but is still slower than Miller Rabin starting at ~1e5 and up to MaxMR. Thus, after this commit, builtin `Integer#prime?` will be similar or faster than `faster_prime` up to "MaxMR".
Adapted from patch of Stephen Blackstone [Feature #16468]
Benchmark results and code: https://gist.github.com/marcandre/b263bdae488e76dabdda84daf73733b9
Co-authored-by: Stephen Blackstone <sblackstone@gmail.com>
Previously, it would be an infinite loop if passed a non-prime
integer.
Also, Prime.include? should also provide similar results to
Module#include? if passed a Module, so handle that.
For consistency with Enumerable#include?, return false if passed
other object types.
Fixes Ruby Bug 10167.
55dda6aa7f
This change improves line coverage of prime.rb from 86% to 99%.
A patch from @shio-phys. https://github.com/ruby/prime/pull/3
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* lib/prime.rb: Use accurate sqrt to insure all factors are tested.
Patch by Marcus Stollsteimer.
* test/test_prime.rb: Adapt test for timeout
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58809 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Adapted from patch by Jabari Zakiya [#12665]
* test/test_prime.rb: Improve test
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When you change this to true, you may need to add more tests.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53141 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* test/test_prime.rb (test_eratosthenes_works_fine_after_timeout):
use assert_raise to check timeout.
* test/test_securerandom.rb: check if results are hexadecimal
strings, and refine failure messages.
* test/test_tracer.rb (test_tracer_with_option_r_without_gems):
use assert_equal to compare.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51023 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* test/test_prime.rb: use more descriptive assertions for better
failure meessages, instead of simple assert.
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by definition. reported by Ivan Kataitsev. [Bug #7395]
* test/test_prime.rb: add test.
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not been displayed when $VERBOSE == nil. Patch by Shota Fukumori
a.k.a. sora_h. [ruby-dev:42272]
Recovers $stderr even if StringIO.new fails. Reported by unak.
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negative integer into a decomposition with element [-1, 1].
* test/test_prime.rb: test for it.
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[ruby-core:22646].
* test/test_prime.rb (test_prime?): test case for [ruby-core:22646].
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