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| author | yugui <yugui@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-07-13 13:51:49 +0000 |
|---|---|---|
| committer | yugui <yugui@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-07-13 13:51:49 +0000 |
| commit | 60558c8cfb878dd1844f3f4a0e78f3fe049f1652 (patch) | |
| tree | f22c154e749662d907df5b6fdb98e3208b8528e0 /lib | |
| parent | aca5106342b1dfbe02e603e5b89a35f317a67289 (diff) | |
| download | ruby-60558c8cfb878dd1844f3f4a0e78f3fe049f1652.tar.gz ruby-60558c8cfb878dd1844f3f4a0e78f3fe049f1652.tar.xz ruby-60558c8cfb878dd1844f3f4a0e78f3fe049f1652.zip | |
* 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: http://svn.ruby-lang.org/repos/ruby/trunk@24091 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'lib')
| -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 50b78d9b0..68253897c 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) |