From 39ea1c8c7c68e2b09c5d2b8641f049f702ca9805 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 23 Sep 2009 17:21:26 +0000
Subject: * ext/bigdecimal/lib/bigdecimal/math.rb (atan): atan(Infinity) is  
 PI/2.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25063 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ext/bigdecimal/lib/bigdecimal/math.rb | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

(limited to 'ext/bigdecimal/lib')

diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb
index d1e8dbe326..eeffde4e68 100644
--- a/ext/bigdecimal/lib/bigdecimal/math.rb
+++ b/ext/bigdecimal/lib/bigdecimal/math.rb
@@ -117,22 +117,16 @@ module BigMath
 
   # Computes the arctangent of x to the specified number of digits of precision.
   #
-  # If x is infinite or NaN, returns NaN.
+  # If x is NaN, returns NaN.
   def atan(x, prec)
     raise ArgumentError, "Zero or negative precision for atan" if prec <= 0
-    return BigDecimal("NaN") if x.infinite? || x.nan?
+    return BigDecimal("NaN") if x.nan?
     pi = PI(prec)
-    if neg = x < 0
-      x = -x
-    end
-    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
+    x = -x if neg = x < 0
+    return pi.div(neg ? -2 : 2, prec) if x.infinite?
+    return pi / (neg ? -4 : 4) if x.round(prec) == 1
+    x = 1 / x if inv = x > 1
+    x = (-1 + sqrt(1 + x**2, prec))/x if dbl = x > 0.5
     n    = prec + BigDecimal.double_fig
     y = x
     d = y
-- 
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