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85 lines
3.0 KiB
Ruby
85 lines
3.0 KiB
Ruby
# require 'bigdecimal'
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describe "BigDecimal#power" do
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@method = :**
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it "powers of self" do
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e3_minus = BigDecimal("3E-21")
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e3_minus_power_2 = BigDecimal("9E-42")
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e3_plus = BigDecimal("3E21")
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e2_plus = BigDecimal("2E41")
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e5_minus = BigDecimal("5E-42")
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e = BigDecimal("1.00000000000000000000123456789")
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one = BigDecimal("1")
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ten = BigDecimal("10")
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# The tolerance is dependent upon the size of BASE_FIG
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tolerance = BigDecimal("1E-70")
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ten_powers = BigDecimal("1E100")
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pi = BigDecimal("3.14159265358979")
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e3_minus.send(@method, 2).should == e3_minus_power_2
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e3_plus.send(@method, 0).should == 1
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e3_minus.send(@method, 1).should == e3_minus
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e2_plus.send(@method, -1).should == e5_minus
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e2_plus.send(@method, -1).should == e5_minus.power(1)
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(e2_plus.send(@method, -1) * e5_minus.send(@method, -1)).should == 1
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e.send(@method, 2).should == e * e
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# e.send(@method, -1).should be_close(one.div(e, 120), tolerance)
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# ten.send(@method, 10000).should == ten_powers
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# pi.send(@method, 10).should be_close(Math::PI ** 10, TOLERANCE)
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end
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it "powers of 1 equal 1" do
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one = BigDecimal("1")
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one.send(@method, 0).should == 1
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one.send(@method, 1).should == 1
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one.send(@method, 10).should == 1
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one.send(@method, -10).should == 1
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end
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it "0 to power of 0 is 1" do
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zero = BigDecimal("0")
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zero.send(@method, 0).should == 1
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end
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# it "0 to powers < 0 is Infinity" do
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# zero = BigDecimal("0")
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# infinity = BigDecimal("Infinity")
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# zero.send(@method, -10).should == infinity
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# zero.send(@method, -1).should == infinity
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# end
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it "other powers of 0 are 0" do
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zero = BigDecimal("0")
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zero.send(@method, 1).should == 0
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zero.send(@method, 10).should == 0
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end
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# it "returns NaN if self is NaN" do
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# BigDecimal("NaN").send(@method, -5).nan?.should == true
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# BigDecimal("NaN").send(@method, 5).nan?.should == true
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# end
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# ruby_version_is "" ... "1.8.8" do
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# it "returns NaN if self is infinite" do
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# BigDecimal("Infinity").send(@method, -5).nan?.should == true
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# BigDecimal("-Infinity").send(@method, -5).nan?.should == true
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# BigDecimal("Infinity").send(@method, 5).nan?.should == true
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# BigDecimal("-Infinity").send(@method, 5).nan?.should == true
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# end
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# end
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# ruby_version_is "1.8.8" do # this behavior may be backported to 1.8.7 [ruby-dev:40182]
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# it "returns 0.0 if self is infinite and argument is negative" do
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# BigDecimal("Infinity").send(@method, -5).should == 0
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# BigDecimal("-Infinity").send(@method, -5).should == 0
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# end
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# it "returns infinite if self is infinite and argument is positive" do
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# infinity = BigDecimal("Infinity")
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# BigDecimal("Infinity").send(@method, 4).should == infinity
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# BigDecimal("-Infinity").send(@method, 4).should == infinity
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# BigDecimal("Infinity").send(@method, 5).should == infinity
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# BigDecimal("-Infinity").send(@method, 5).should == -infinity
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# end
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# end
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end
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