module Combinatorics::CartesianProduct
@author duper <super@manson.vistech.net>
@since 0.4.0
Public Class Methods
X(a,b)
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@note The letter `X' is scholastic notation for the Cartesian product
set operation
@see cardinality
# File lib/combinatorics/cartesian_product/cardinality.rb, line 41 def self.X(a,b) cardinality(a,b) end
cardinality(a,b)
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Wrapper for Cartesian product cardinality method defined above
@param [Fixnum] a
Cardinality of first set.
@param [Fixnum] b
Cardinality of second set.
@raise [RangeError]
Inputs must be greater than zero.
@return [Fixnum]
Length of enumeration resulting from a Cartesian product.
@example Calculate elements in Cartesian product of two equal-size sets
cardinality(3, 4) # => 12
# File lib/combinatorics/cartesian_product/cardinality.rb, line 27 def self.cardinality(a,b) if (a <= 0 || b <= 0) raise(RangeError,"inputs must be greater than zero") end a * b end