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401b64c4e8
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62656 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
44 lines
1.5 KiB
Ruby
44 lines
1.5 KiB
Ruby
require_relative '../../spec_helper'
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require_relative 'fixtures/classes'
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# erf method is the "error function" encountered in integrating the normal
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# distribution (which is a normalized form of the Gaussian function).
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describe "Math.erf" do
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it "returns a float" do
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Math.erf(1).should be_kind_of(Float)
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end
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it "returns the error function of the argument" do
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Math.erf(0).should be_close(0.0, TOLERANCE)
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Math.erf(1).should be_close(0.842700792949715, TOLERANCE)
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Math.erf(-1).should be_close(-0.842700792949715, TOLERANCE)
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Math.erf(0.5).should be_close(0.520499877813047, TOLERANCE)
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Math.erf(-0.5).should be_close(-0.520499877813047, TOLERANCE)
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Math.erf(10000).should be_close(1.0, TOLERANCE)
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Math.erf(-10000).should be_close(-1.0, TOLERANCE)
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Math.erf(0.00000000000001).should be_close(0.0, TOLERANCE)
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Math.erf(-0.00000000000001).should be_close(0.0, TOLERANCE)
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end
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it "raises a TypeError if the argument cannot be coerced with Float()" do
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lambda { Math.erf("test") }.should raise_error(TypeError)
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end
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it "returns NaN given NaN" do
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Math.erf(nan_value).nan?.should be_true
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end
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it "raises a TypeError if the argument is nil" do
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lambda { Math.erf(nil) }.should raise_error(TypeError)
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end
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it "accepts any argument that can be coerced with Float()" do
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Math.erf(MathSpecs::Float.new).should be_close(0.842700792949715, TOLERANCE)
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end
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end
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describe "Math#erf" do
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it "is accessible as a private instance method" do
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IncludesMath.new.send(:erf, 3.1415).should be_close(0.999991118444483, TOLERANCE)
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end
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end
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