Contents

describe Integer, "#semiperfect?" do
  SEMI_PERFECT = [6,12,18,20,24,28,30,36,40,42,48,54,56,60,66,72,
                  78,80,84,88,90,96,100,102,104,108,112,114,120,126,
                  132,138,140,144,150,156,160,162,168,174,176,180,
                  186,192,196,198,200,204,208,210,216,220,222,224,
                  228,234,240,246,252,258,260,264]
  it "returns true if the number is semi-perfect" do
    SEMI_PERFECT.each do |number|
      number.should be_semiperfect
    end
  end

  it "returns true if the number is a multiple of a known semi-perfect" do
    (SEMI_PERFECT.combination(2).map{|_| _.reduce(:*)}.uniq - SEMI_PERFECT).
      shuffle.first(15).each do |number|
      number.should be_semiperfect
    end
  end

  # Guy, R. K. 
  # "Almost Perfect, Quasi-Perfect, Pseudoperfect, Harmonic, Weird, Multiperfect and Hyperperfect Numbers." 
  # §B2 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 45-53, 1994
  it "returns true for 2**m * p (where m >= 1 && p.prime? && (p < 2**(m+1) && p > 2**m)" do
    [[4, 17], [4, 19], [4, 23], [4, 29], [4, 31], 
     [5, 37], [5, 41], [5, 43], [5, 47], [5, 53], [5, 59], [5, 61],
     [6, 67], [6, 71], [6, 73], [6, 79], [6, 83], [6, 89], [6, 97],
     [6, 101],[6, 103],[6, 107],[6, 109],[6, 113],[6, 127]].shuffle.first(10).each do |m,p|
      (2**m * p).should be_semiperfect
    end
  end

  it "returns false if the number is not semi-perfect" do
    ((1..263).to_a - SEMI_PERFECT).each do |number|
      number.should_not be_semiperfect
    end
  end

  it "returns false if the number is negative" do
    (1..263).each do |number|
      (-number).should_not be_semiperfect
    end
  end

  it "handles large input quickly and without raising a RangeError" do
    require 'timeout'
    lambda do 
      Timeout.timeout(5) { 19305.semiperfect? }
    end.should_not raise_error
  end
end

Version data entries

8 entries across 8 versions & 1 rubygems

Version	Path
numb-0.72.1	spec/semi_perfect_spec.rb
numb-0.72.0	spec/semi_perfect_spec.rb
numb-0.68.0	spec/semi_perfect_spec.rb
numb-0.63.0	spec/semi_perfect_spec.rb
numb-0.21.0	spec/semi_perfect_spec.rb
numb-0.20.0	spec/semi_perfect_spec.rb
numb-0.10.0	spec/semi_perfect_spec.rb
numb-0.9.0	spec/semi_perfect_spec.rb