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author | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-09-23 12:25:20 +0000 |
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committer | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-09-23 12:25:20 +0000 |
commit | e6f7edacea92b39e118a9a82ed7a83b2b428a52b (patch) | |
tree | e74afa9dbc0a64adda06381b1c51e0412b6980d5 | |
parent | 8f941978648f04e9d76cec4761722c10a69ad9f5 (diff) | |
download | ruby-e6f7edacea92b39e118a9a82ed7a83b2b428a52b.tar.gz ruby-e6f7edacea92b39e118a9a82ed7a83b2b428a52b.tar.xz ruby-e6f7edacea92b39e118a9a82ed7a83b2b428a52b.zip |
* ext/bigdecimal/lib/bigdecimal/math.rb (atan): refined.
git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@25057 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r-- | ChangeLog | 4 | ||||
-rw-r--r-- | ext/bigdecimal/lib/bigdecimal/math.rb | 11 |
2 files changed, 15 insertions, 0 deletions
@@ -1,3 +1,7 @@ +Wed Sep 23 21:25:20 2009 Nobuyoshi Nakada <nobu@ruby-lang.org> + + * ext/bigdecimal/lib/bigdecimal/math.rb (atan): refined. + Wed Sep 23 17:08:30 2009 Nobuyoshi Nakada <nobu@ruby-lang.org> * parse.y (assign_in_cond): also should warn assignment to dvar in diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb index 2771c77b6..dbc058b0b 100644 --- a/ext/bigdecimal/lib/bigdecimal/math.rb +++ b/ext/bigdecimal/lib/bigdecimal/math.rb @@ -121,6 +121,15 @@ module BigMath def atan(x, prec) raise ArgumentError, "Zero or negative precision for atan" if prec <= 0 return BigDecimal("NaN") if x.infinite? || x.nan? + pi = PI(prec) + if neg = x < 0 + x = -x + end + if x == 1 + return pi / (neg ? -4 : 4) + elsif inv = x > 1 + x = 1 / x + end n = prec + BigDecimal.double_fig y = x d = y @@ -134,6 +143,8 @@ module BigMath y += d r += 2 end + y = pi / 2 - y if inv + y = -y if neg y end |