53 lines
2.3 KiB
Crystal
53 lines
2.3 KiB
Crystal
include Stats
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describe Math do
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it "binomial_distribution" do
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0.0.step(by: 0.1, to: 1.0) do |proba|
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Math.binomial_distribution(tries: 1, probability: proba, success: 1).should eq(proba)
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end
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Math.binomial_distribution(tries: 10, probability: 0.2, success: 3).round(3).should eq(0.201)
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Math.binomial_distribution(tries: 10, probability: 0.2, success: 6).round(4).should eq(0.0055)
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end
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end
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describe BinomialDistribution do
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it "initialize" do
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BinomialDistribution(Int32, Float64).new(0).should be_a(BinomialDistribution(Int32, Float64))
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BinomialDistribution(Int32, Float64).new(1).should be_a(BinomialDistribution(Int32, Float64))
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BinomialDistribution(Int32, Float64).new(100).should be_a(BinomialDistribution(Int32, Float64))
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BinomialDistribution(Int32, Int32).new(1, 0).should be_a(BinomialDistribution(Int32, Int32))
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BinomialDistribution.new(1, 0.5).should be_a(BinomialDistribution(Int32, Float64))
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BinomialDistribution.new(1, 1).should be_a(BinomialDistribution(Int32, Int32))
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end
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it "initialize errors" do
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expect_raises(Math::DomainError) { BinomialDistribution(Int32, Float64).new(-1) }
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expect_raises(Math::DomainError) { BinomialDistribution.new(0, -1) }
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expect_raises(Math::DomainError) { BinomialDistribution.new(0, 1.5) }
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end
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it "distribute" do
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b = BinomialDistribution.new(2, 0.5)
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b.should be_a(BinomialDistribution(Int32, Float64))
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b.distribute(0).should eq 0.25
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b.distribute(1).should eq 0.5
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b.distribute(2).should eq 0.25
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b.distribute([0, 2]).should eq 0.5
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b.distribute([0, 1]).should eq 0.75
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b.distribute([2, 1]).should eq 0.75
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end
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it "with spaces tests" do
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end
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it "with BitNumber" do
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BinomialDistribution.new(BigInt.new(1), BigFloat.new(1)).should be_a(BinomialDistribution(BigInt, BigFloat))
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((a = BinomialDistribution.new(BigInt.new(10), BigFloat.new(0.02)).distribute(BigInt.new(1)..BigInt.new(10))) > 0.02).should be_true
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((b = BinomialDistribution.new(BigInt.new(20), BigFloat.new(0.02)).distribute(BigInt.new(1)..BigInt.new(20))) > 0.02).should be_true
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((c = BinomialDistribution.new(BigInt.new(50), BigFloat.new(0.02)).distribute(BigInt.new(1)..BigInt.new(50))) > 0.02).should be_true
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(b > a).should be_true
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(c > b).should be_true
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# p a, b, c
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end
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end
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