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author | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-09-23 17:08:37 +0000 |
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committer | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-09-23 17:08:37 +0000 |
commit | 1ef3ac47384e27817f45864f65162fbc04a5d12f (patch) | |
tree | fab96e351bf6b1b24cd069b8782d6a641d17b40a | |
parent | 12fcef8829b9f514a517c606bd783eaffb401318 (diff) | |
download | ruby-1ef3ac47384e27817f45864f65162fbc04a5d12f.tar.gz |
* ext/bigdecimal/lib/bigdecimal/math.rb (atan): reduce loop with
the formula of the double corner. based on a patch from
Masahiro Kanai (CanI) in [ruby-dev:39367].
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25062 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r-- | ChangeLog | 6 | ||||
-rw-r--r-- | ext/bigdecimal/lib/bigdecimal/math.rb | 6 |
2 files changed, 11 insertions, 1 deletions
@@ -1,3 +1,9 @@ +Thu Sep 24 02:08:35 2009 Nobuyoshi Nakada <nobu@ruby-lang.org> + + * ext/bigdecimal/lib/bigdecimal/math.rb (atan): reduce loop with + the formula of the double corner. based on a patch from + Masahiro Kanai (CanI) in [ruby-dev:39367]. + Thu Sep 24 01:14:18 2009 Yutaka Kanemoto <kanemoto@ruby-lang.org> * dln.c (aix_loaderror): fixed typo. suppress warnings. diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb index dbc058b0b3..d1e8dbe326 100644 --- a/ext/bigdecimal/lib/bigdecimal/math.rb +++ b/ext/bigdecimal/lib/bigdecimal/math.rb @@ -125,11 +125,14 @@ module BigMath if neg = x < 0 x = -x end - if x == 1 + if x.round(prec) == 1 return pi / (neg ? -4 : 4) elsif inv = x > 1 x = 1 / x end + if dbl = x > 0.5 + x = (-1 + sqrt(1 + x**2, prec))/x + end n = prec + BigDecimal.double_fig y = x d = y @@ -143,6 +146,7 @@ module BigMath y += d r += 2 end + y *= 2 if dbl y = pi / 2 - y if inv y = -y if neg y |