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* lib/prime.rb: Corrected a few comments. Patch by @Nullset14.
Fixes GH-346. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41714 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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2 changed files with 23 additions and 18 deletions
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@ -1,3 +1,8 @@
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Sun Jun 30 22:40:00 2013 Charlie Somerville <charliesome@ruby-lang.org>
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* lib/prime.rb: Corrected a few comments. Patch by @Nullset14.
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Fixes GH-346.
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Sun Jun 30 21:53:38 2013 Tanaka Akira <akr@fsij.org>
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* bignum.c (rb_cstr_to_inum): Use rb_integer_unpack if base is a power
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36
lib/prime.rb
36
lib/prime.rb
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@ -71,20 +71,20 @@ end
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#
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# A "generator" provides an implementation of enumerating pseudo-prime
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# numbers and it remembers the position of enumeration and upper bound.
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# Furthermore, it is a external iterator of prime enumeration which is
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# compatible to an Enumerator.
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# Furthermore, it is an external iterator of prime enumeration which is
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# compatible with an Enumerator.
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#
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# +Prime+::+PseudoPrimeGenerator+ is the base class for generators.
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# There are few implementations of generator.
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#
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# [+Prime+::+EratosthenesGenerator+]
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# Uses eratosthenes's sieve.
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# Uses eratosthenes' sieve.
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# [+Prime+::+TrialDivisionGenerator+]
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# Uses the trial division method.
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# [+Prime+::+Generator23+]
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# Generates all positive integers which is not divided by 2 nor 3.
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# Generates all positive integers which are not divisible by either 2 or 3.
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# This sequence is very bad as a pseudo-prime sequence. But this
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# is faster and uses much less memory than other generators. So,
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# is faster and uses much less memory than the other generators. So,
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# it is suitable for factorizing an integer which is not large but
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# has many prime factors. e.g. for Prime#prime? .
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@ -133,13 +133,13 @@ class Prime
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# a parameter.
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#
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# +ubound+::
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# Upper bound of prime numbers. The iterator stops after
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# Upper bound of prime numbers. The iterator stops after it
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# yields all prime numbers p <= +ubound+.
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#
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# == Note
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#
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# +Prime+.+new+ returns a object extended by +Prime+::+OldCompatibility+
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# in order to compatibility to Ruby 1.8, and +Prime+#each is overwritten
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# +Prime+.+new+ returns an object extended by +Prime+::+OldCompatibility+
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# in order to be compatible with Ruby 1.8, and +Prime+#each is overwritten
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# by +Prime+::+OldCompatibility+#+each+.
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#
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# +Prime+.+new+ is now obsolete. Use +Prime+.+instance+.+each+ or simply
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@ -191,9 +191,9 @@ class Prime
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# +value+:: An arbitrary integer.
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# +generator+:: Optional. A pseudo-prime generator.
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# +generator+.succ must return the next
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# pseudo-prime number in the ascendent
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# pseudo-prime number in the ascending
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# order. It must generate all prime numbers,
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# but may generate non prime numbers.
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# but may also generate non prime numbers too.
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#
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# === Exceptions
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# +ZeroDivisionError+:: when +value+ is zero.
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@ -209,7 +209,7 @@ class Prime
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#
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# Prime.prime_division(12) #=> [[2,2], [3,1]]
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#
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def prime_division(value, generator= Prime::Generator23.new)
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def prime_division(value, generator = Prime::Generator23.new)
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raise ZeroDivisionError if value == 0
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if value < 0
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value = -value
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@ -272,7 +272,7 @@ class Prime
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raise NotImplementedError, "need to define `rewind'"
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end
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# Iterates the given block for each prime numbers.
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# Iterates the given block for each prime number.
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def each(&block)
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return self.dup unless block
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if @ubound
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@ -336,11 +336,11 @@ class Prime
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alias next succ
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end
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# Generates all integer which are greater than 2 and
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# are not divided by 2 nor 3.
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# Generates all integers which are greater than 2 and
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# are not divisible by either 2 or 3.
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#
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# This is a pseudo-prime generator, suitable on
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# checking primality of a integer by brute force
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# checking primality of an integer by brute force
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# method.
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class Generator23<PseudoPrimeGenerator
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def initialize
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@ -418,7 +418,7 @@ class Prime
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end
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end
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# Internal use. An implementation of eratosthenes's sieve
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# Internal use. An implementation of eratosthenes' sieve
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class EratosthenesSieve
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include Singleton
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@ -456,7 +456,7 @@ class Prime
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end
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private
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# for an odd number +n+, returns (i, j, k) such that @tables[i][j][k] represents primarity of the number
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# for an odd number +n+, returns (i, j, k) such that @tables[i][j][k] represents primality of the number
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def indices(n)
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# binary digits of n: |0|1|2|3|4|5|6|7|8|9|10|11|....
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# indices: |-| k | j | i
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@ -471,7 +471,7 @@ class Prime
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def extend_table
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lbound = NUMS_PER_TABLE * @tables.length
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ubound = lbound + NUMS_PER_TABLE
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new_table = [FILLED_ENTRY] * ENTRIES_PER_TABLE # which represents primarity in lbound...ubound
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new_table = [FILLED_ENTRY] * ENTRIES_PER_TABLE # which represents primality in lbound...ubound
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(3..Integer(Math.sqrt(ubound))).step(2) do |p|
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i, j, k = indices(p)
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next if @tables[i][j][k].zero?
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