* ext/bigdecimal/lib/bigdecimal/math.rb (sin, cos, atan, exp, log):

  improved precision and performance.  based on a patch from Makoto
  Yamashita in [ruby-core:25600] and [ruby-core:25602].


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@25013 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 77 insertions, 0 deletions

diff --git a/test/bigdecimal/test_bigmath.rb b/test/bigdecimal/test_bigmath.rb
new file mode 100644
index 0000000000..7801e6045b
--- /dev/null
+++ b/test/bigdecimal/test_bigmath.rb
@@ -0,0 +1,77 @@
+require "test/unit"
+require "bigdecimal"
+require "bigdecimal/math"
+
+class TestBigMath < Test::Unit::TestCase
+  include BigMath
+  N = 20
+  PINF = BigDecimal("+Infinity")
+  MINF = BigDecimal("-Infinity")
+  NAN = BigDecimal("NaN")
+
+  def test_const
+    assert_in_delta(Math::PI, PI(N))
+    assert_in_delta(Math::E, E(N))
+  end
+
+  def test_sqrt
+    assert_in_delta(2**0.5, sqrt(BigDecimal("2"), N))
+    assert_equal(10, sqrt(BigDecimal("100"), N))
+    assert_equal(0.0, sqrt(BigDecimal("0"), N))
+    assert_equal(0.0, sqrt(BigDecimal("-0"), N))
+    assert_raise(FloatDomainError) {sqrt(BigDecimal("-1.0"), N)}
+    assert_raise(FloatDomainError) {sqrt(NAN, N)}
+    assert_equal(PINF, sqrt(PINF, N))
+  end
+
+  def test_sin
+    assert_in_delta(0.0, sin(BigDecimal("0.0"), N))
+    assert_in_delta(Math.sqrt(2.0) / 2, sin(PI(N) / 4, N))
+    assert_in_delta(1.0, sin(PI(N) / 2, N))
+    assert_in_delta(0.0, sin(PI(N) * 2, N))
+    assert_in_delta(0.0, sin(PI(N), N))
+    assert_in_delta(-1.0, sin(PI(N) / -2, N))
+    assert_in_delta(0.0, sin(PI(N) * -2, N))
+    assert_in_delta(0.0, sin(-PI(N), N))
+    assert_in_delta(0.0, sin(PI(N) * 21, N))
+    assert_in_delta(0.0, sin(PI(N) * 30, N))
+    assert_in_delta(-1.0, sin(PI(N) * BigDecimal("301.5"), N))
+  end
+
+  def test_cos
+    assert_in_delta(1.0, cos(BigDecimal("0.0"), N))
+    assert_in_delta(Math.sqrt(2.0) / 2, cos(PI(N) / 4, N))
+    assert_in_delta(0.0, cos(PI(N) / 2, N))
+    assert_in_delta(1.0, cos(PI(N) * 2, N))
+    assert_in_delta(-1.0, cos(PI(N), N))
+    assert_in_delta(0.0, cos(PI(N) / -2, N))
+    assert_in_delta(1.0, cos(PI(N) * -2, N))
+    assert_in_delta(-1.0, cos(-PI(N), N))
+    assert_in_delta(-1.0, cos(PI(N) * 21, N))
+    assert_in_delta(1.0, cos(PI(N) * 30, N))
+    assert_in_delta(0.0, cos(PI(N) * BigDecimal("301.5"), N))
+  end
+
+  def test_atan
+    assert_equal(0.0, atan(BigDecimal("0.0"), N))
+    assert_in_delta(Math::PI/4, atan(BigDecimal("1.0"), N))
+    assert_in_delta(Math::PI/6, atan(sqrt(BigDecimal("3.0"), N) / 3, N))
+  end
+
+  def test_exp
+    assert_in_epsilon(Math::E, exp(BigDecimal("1"), N))
+    assert_in_epsilon(Math.exp(N), exp(BigDecimal("20"), N))
+    assert_in_epsilon(Math.exp(40), exp(BigDecimal("40"), N))
+    assert_in_epsilon(Math.exp(-N), exp(BigDecimal("-20"), N))
+    assert_in_epsilon(Math.exp(-40), exp(BigDecimal("-40"), N))
+  end
+
+  def test_log
+    assert_in_delta(0.0, log(BigDecimal("1"), N))
+    assert_in_delta(1.0, log(E(N), N))
+    assert_in_delta(Math.log(2.0), log(BigDecimal("2"), N))
+    assert_in_delta(2.0, log(E(N)*E(N), N))
+    assert_in_delta(Math.log(42.0), log(BigDecimal("42"), N))
+    assert_in_delta(Math.log(1e-42), log(BigDecimal("1e-42"), N))
+  end
+end