Markov chains for fun
and profit

"It is fatal to enter any war without the software."

- GenMacArthurC.Clarke @GenMcArtCClarke

"People respond in accordance to how you relate to them and play the guitar."

- Willie Nelson Mandela @WillieNelMan

Quote Masher

What are Markov Chains?

According to WikiPedia

"A Markov Chain is a random process that undergoes transitions from one state to another on a state space"

State Machines

Behaving Randomly

Deterministic State Machines

Markov Chains are Non-Deterministic

"memoryless"

Applications for
Markov Chains

Simulating Moods

Simulating Stocks

Simulating Weather

Complex Chains

Text processing

"George Lucas doesn't have the duty to do good."

- PopeFranFordCoppola @PopeFranFordCop

An Example Deconstructed

"Never tell people how to make
good fried rice."

- GeorgePattonOswalt @GeorgePattonOz

"Never tell people how to do things."

- General George Patton

"I know how to make good fried rice."

- Patton Oswalt

Probability Function

Choose your own adventure

Quote Masher Admin Demo

OR

Let's see some code!

How would you code this?

Starting with tests, of course!

  RSpec.describe MarkovChainer do
    before :each do
      @chainer = MarkovChainer.new
    end
    # ...
  end

  RSpec.describe MarkovChainer do
    # ...
    describe "#train" do
      it "should accept a sentence" do
        expect {
          @chainer.train("This is a test message")
        }.to_not raise_error
      end
    end
    #...
  end

  RSpec.describe MarkovChainer do
    #...
    describe "#generate with one sentece" do
      it "should return the original sentence" do
        @sentence = "This should come back un-changed."
        @chainer.train(@sentence)
        expect(@chainer.generate).to eq(@sentence)
      end
    end
    #...
  end

  RSpec.describe MarkovChainer do
    describe "#generate with two sentences" do
      it "should mix the sentences" do
        @chainer.train("Rob loves Ruby")
        @chainer.train("Jesse loves Javascript")
        results = {}
        20.times do
          new_sentence = @chainer.generate
          results[new_sentence] ||= 0
          results[new_sentence] += 1
        end
        puts results
        expect(results["Rob loves Javascript"]).to be > 0
      end
    end
  end

  # results
  {
    "Jesse loves Ruby" => 7,
    "Rob loves Ruby" => 5,
    "Rob loves Javascript" => 4,
    "Jesse loves Javascript" => 4
  }

Make with the live coding already!

Quote Masher
Admin Demo

"In war you win or lose live or die - and half the things a man knows at 40 hadn't been discovered when he is very probably wrong"

- GenMacArthurC.Clarke @GenMcArtCClarke

"Every revolutionary idea is just returned from visiting the stars."

- GenMacArthurC.Clarke @GenMcArtCClarke

"Any sufficiently advanced technology is very probably wrong"

- GenMacArthurC.Clarke @GenMcArtCClarke

"The greatest tragedy in mankind's entire history may be summed up by the press and other forms of nationalism."

- GenMacArthurC.Clarke @GenMcArtCClarke

"Our government has kept us in a world where half the things a man knows at 40 hadn't been discovered when he is very probably wrong"

- GenMacArthurC.Clarke @GenMcArtCClarke

"The best luck of all is the fact that flags do not wave in a constant conspiracy against the stars."

- GenMacArthurC.Clarke @GenMcArtCClarke

"Reading computer manuals without the hardware is as frustrating as reading sex manuals without the support of public opinion."

- GenMacArthurC.Clarke @GenMcArtCClarke

"Americans accept judicial supervision of their income so that the political class will not respect the boundaries he is pushing as Borat."

- George Will Ferrel @GeorgeWilFerrel

"I mean it's tough for me to play Simon Cowell in a position where you can make choices regardless of money."

- George Will Ferrel @GeorgeWilFerrel

"Often times I'm confronted with a limited budget and we really felt strongly that we could live with a slice of processed cheese."

- George Will Ferrel @GeorgeWilFerrel

"The internet in hotels should be free - and it's the fundamental thing - the mercy of God has no limits."

- PopeFranFordCoppola @PopeFranFordCop

"I don't want to be particularly clear you've probably misunderstood what I've said."

- WoodyAllenGreenspan @WoodyAGreenspan

"Seventy percent of success in life is that I am not afraid of death I just don't want to be there when it happens."

- WoodyAllenGreenspan @WoodyAGreenspan

"In Beverly Hills they turn out to 'freedom-kiss' my music business on the corporate sector."

- WoodyAllenGreenspan @WoodyAGreenspan

"My one regret in life is showing up."

- WoodyAllenGreenspan @WoodyAGreenspan

"You're going to go through life defeated and not having enough money."

- Billy Joel Osteen @BillyJoelOsteen