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author | yugui <yugui@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-07-13 13:51:49 +0000 |
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committer | yugui <yugui@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-07-13 13:51:49 +0000 |
commit | 7287b852da95b3bee1395fd80752e62b686da294 (patch) | |
tree | f22c154e749662d907df5b6fdb98e3208b8528e0 /lib/prime.rb | |
parent | 0fefd1902329f72434e859bd77a7ea5a114c00ff (diff) | |
download | ruby-7287b852da95b3bee1395fd80752e62b686da294.tar.gz |
* lib/prime.rb (Prime#prime_division): now decomposes
negative integer into a decomposition with element [-1, 1].
* test/test_prime.rb: test for it.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24091 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'lib/prime.rb')
-rw-r--r-- | lib/prime.rb | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/lib/prime.rb b/lib/prime.rb index 50b78d9b0e..68253897ca 100644 --- a/lib/prime.rb +++ b/lib/prime.rb @@ -194,7 +194,12 @@ class Prime # def prime_division(value, generator= Prime::Generator23.new) raise ZeroDivisionError if value == 0 - pv = [] + if value < 0 + value = -value + pv = [[-1, 1]] + else + pv = [] + end for prime in generator count = 0 while (value1, mod = value.divmod(prime) |