Imported minitest 4.7.4 (r8483)

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40553 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 43 insertions, 0 deletions

diff --git a/lib/minitest/benchmark.rb b/lib/minitest/benchmark.rb
index 02121db340..e233282b0a 100644
--- a/lib/minitest/benchmark.rb
+++ b/lib/minitest/benchmark.rb
@@ -163,6 +163,26 @@ class MiniTest::Unit # :nodoc:
 
     ##
     # Runs the given +work+ and asserts that the times gathered fit to
+    # match a logarithmic curve within a given error +threshold+.
+    #
+    # Fit is calculated by #fit_logarithmic.
+    #
+    # Ranges are specified by ::bench_range.
+    #
+    # Eg:
+    #
+    #   def bench_algorithm
+    #     assert_performance_logarithmic 0.9999 do |n|
+    #       @obj.algorithm(n)
+    #     end
+    #   end
+
+    def assert_performance_logarithmic threshold = 0.99, &work
+      assert_performance validation_for_fit(:logarithmic, threshold), &work
+    end
+
+    ##
+    # Runs the given +work+ and asserts that the times gathered fit to
     # match a straight line within a given error +threshold+.
     #
     # Fit is calculated by #fit_linear.
@@ -237,6 +257,29 @@ class MiniTest::Unit # :nodoc:
     end
 
     ##
+    # To fit a functional form: y = a + b*ln(x).
+    #
+    # Takes x and y values and returns [a, b, r^2].
+    #
+    # See: http://mathworld.wolfram.com/LeastSquaresFittingLogarithmic.html
+
+    def fit_logarithmic xs, ys
+      n     = xs.size
+      xys   = xs.zip(ys)
+      slnx2 = sigma(xys) { |x,y| Math.log(x) ** 2 }
+      slnx  = sigma(xys) { |x,y| Math.log(x)      }
+      sylnx = sigma(xys) { |x,y| y * Math.log(x)  }
+      sy    = sigma(xys) { |x,y| y                }
+
+      c = n * slnx2 - slnx ** 2
+      b = ( n * sylnx - sy * slnx ) / c
+      a = (sy - b * slnx) / n
+
+      return a, b, fit_error(xys) { |x| a + b * Math.log(x) }
+    end
+
+
+    ##
     # Fits the functional form: a + bx.
     #
     # Takes x and y values and returns [a, b, r^2].