matrix multiplying

multiplying.rb

def multiply m_1, m_2
  m_2 = m_2.reduce(:zip).map(&:flatten)
  m_1.collect do |i|
    m_2.collect do |j|
      i.zip(j).map{|k| k.reduce(:*)}.reduce(:+)
    end
  end
end

m_1 = Array.new(2){Array.new(2){rand}}
m_2 = Array.new(2){Array.new(2){rand}}

puts "Matrix 1:\n"
puts m_1.map(&:inspect)
puts "Matrix 2:\n"
puts m_2.map(&:inspect)
puts "Result:\n"
puts (multiply m_1, m_2).map(&:inspect)

require 'minitest/spec'
require 'minitest/autorun'

describe "multiply" do
  it "passes" do
  	multiply([[0.0, -0.25],[0.25, 0.0]],
  		    [[0.0, -0.25],[0.25, 0.0]]).must_equal [[-0.0625, -0.0], [0.0, -0.0625]]
  end
end