diff options
| author | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-09-23 17:21:26 +0000 |
|---|---|---|
| committer | nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2009-09-23 17:21:26 +0000 |
| commit | 39ea1c8c7c68e2b09c5d2b8641f049f702ca9805 (patch) | |
| tree | 4acfdf113505668bec6bf86d80e2933370e6b1ff /ext/bigdecimal/lib | |
| parent | 1ef3ac47384e27817f45864f65162fbc04a5d12f (diff) | |
* 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
Diffstat (limited to 'ext/bigdecimal/lib')
| -rw-r--r-- | ext/bigdecimal/lib/bigdecimal/math.rb | 20 |
1 files changed, 7 insertions, 13 deletions
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 |