diff options
| -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 |