Module: Combinatorics::PowerSet

Defined in:

lib/combinatorics/power_set/mixin.rb,
lib/combinatorics/power_set/cardinality.rb

Defined Under Namespace

Modules: Mixin

Class Method Summary

• .cardinality(n) ⇒ Fixnum

  Get number of elements in power set from number of elements in input set.

• .P(n) ⇒ Object

  Wrapper function for power set cardinality method defined above.

Class Method Details

.cardinality(n) ⇒ Fixnum

Note:

Cardinality of power set on an empty set equals factorial(0) equals 1.

Get number of elements in power set from number of elements in input set.

Parameters:

• n (Fixnum) —

  Number of elements input set.

Returns:

• (Fixnum) —

  Number of elements in power set.

See Also:

• Math::factorial
• http://en.wikipedia.org/wiki/Cardinality

# File 'lib/combinatorics/power_set/cardinality.rb', line 24

def self.cardinality(n)
  Math.factorial(n)
end

.P(n) ⇒ Object

Note:

The letter `P' stands for the power set function in the context of statements regarding discrete mathematics.

Wrapper function for power set cardinality method defined above

# File 'lib/combinatorics/power_set/cardinality.rb', line 34

def self.P(n)
  cardinality(n)
end