Gittins Index for a simple example












3












$begingroup$


Everything I can find on the Gittins Index is extremely in depth and abstract with almost no examples. I have spent hours digging through academic papers, lecture notes, and Wikipedia sources. I understand the Gittins Index conceptually, but I would like to include it in program, so I need to know how to compute it (even if the algorithm has a complexity of n factorial).



Is there anyone who can actually solve a simple example like the one below?



This is a version of the classic multi-armed-bandit problem:

I'm at a casino, there are 3 machines M_1, M_2, M_3

Every machine pays out $1 for a win, $0 for a loss

I've played M_1 three times, it has 2 wins 1 loss

I've played M_2 four times, it has 2 wins 2 losses

I've played M_3 two times, it has 1 win 1 loss



If I discount future payouts by 50%;

What is the Gittins Index of M_1?

(An actual number in decimal form)

What steps do you take to get that number?

(Pseudo code would be great)



Thanks for at least reading the problem










share|cite|improve this question









$endgroup$












  • $begingroup$
    I have now asked my statistics professor, linear algebra professor, theoretical computer science professor, and a computer science faculty member all at Texas A&M and none of them had heard of the Gittins Index.
    $endgroup$
    – Jeff Hykin
    Oct 22 '17 at 20:56
















3












$begingroup$


Everything I can find on the Gittins Index is extremely in depth and abstract with almost no examples. I have spent hours digging through academic papers, lecture notes, and Wikipedia sources. I understand the Gittins Index conceptually, but I would like to include it in program, so I need to know how to compute it (even if the algorithm has a complexity of n factorial).



Is there anyone who can actually solve a simple example like the one below?



This is a version of the classic multi-armed-bandit problem:

I'm at a casino, there are 3 machines M_1, M_2, M_3

Every machine pays out $1 for a win, $0 for a loss

I've played M_1 three times, it has 2 wins 1 loss

I've played M_2 four times, it has 2 wins 2 losses

I've played M_3 two times, it has 1 win 1 loss



If I discount future payouts by 50%;

What is the Gittins Index of M_1?

(An actual number in decimal form)

What steps do you take to get that number?

(Pseudo code would be great)



Thanks for at least reading the problem










share|cite|improve this question









$endgroup$












  • $begingroup$
    I have now asked my statistics professor, linear algebra professor, theoretical computer science professor, and a computer science faculty member all at Texas A&M and none of them had heard of the Gittins Index.
    $endgroup$
    – Jeff Hykin
    Oct 22 '17 at 20:56














3












3








3


1



$begingroup$


Everything I can find on the Gittins Index is extremely in depth and abstract with almost no examples. I have spent hours digging through academic papers, lecture notes, and Wikipedia sources. I understand the Gittins Index conceptually, but I would like to include it in program, so I need to know how to compute it (even if the algorithm has a complexity of n factorial).



Is there anyone who can actually solve a simple example like the one below?



This is a version of the classic multi-armed-bandit problem:

I'm at a casino, there are 3 machines M_1, M_2, M_3

Every machine pays out $1 for a win, $0 for a loss

I've played M_1 three times, it has 2 wins 1 loss

I've played M_2 four times, it has 2 wins 2 losses

I've played M_3 two times, it has 1 win 1 loss



If I discount future payouts by 50%;

What is the Gittins Index of M_1?

(An actual number in decimal form)

What steps do you take to get that number?

(Pseudo code would be great)



Thanks for at least reading the problem










share|cite|improve this question









$endgroup$




Everything I can find on the Gittins Index is extremely in depth and abstract with almost no examples. I have spent hours digging through academic papers, lecture notes, and Wikipedia sources. I understand the Gittins Index conceptually, but I would like to include it in program, so I need to know how to compute it (even if the algorithm has a complexity of n factorial).



Is there anyone who can actually solve a simple example like the one below?



This is a version of the classic multi-armed-bandit problem:

I'm at a casino, there are 3 machines M_1, M_2, M_3

Every machine pays out $1 for a win, $0 for a loss

I've played M_1 three times, it has 2 wins 1 loss

I've played M_2 four times, it has 2 wins 2 losses

I've played M_3 two times, it has 1 win 1 loss



If I discount future payouts by 50%;

What is the Gittins Index of M_1?

(An actual number in decimal form)

What steps do you take to get that number?

(Pseudo code would be great)



Thanks for at least reading the problem







decision-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Oct 15 '17 at 16:02









Jeff HykinJeff Hykin

615




615












  • $begingroup$
    I have now asked my statistics professor, linear algebra professor, theoretical computer science professor, and a computer science faculty member all at Texas A&M and none of them had heard of the Gittins Index.
    $endgroup$
    – Jeff Hykin
    Oct 22 '17 at 20:56


















  • $begingroup$
    I have now asked my statistics professor, linear algebra professor, theoretical computer science professor, and a computer science faculty member all at Texas A&M and none of them had heard of the Gittins Index.
    $endgroup$
    – Jeff Hykin
    Oct 22 '17 at 20:56
















$begingroup$
I have now asked my statistics professor, linear algebra professor, theoretical computer science professor, and a computer science faculty member all at Texas A&M and none of them had heard of the Gittins Index.
$endgroup$
– Jeff Hykin
Oct 22 '17 at 20:56




$begingroup$
I have now asked my statistics professor, linear algebra professor, theoretical computer science professor, and a computer science faculty member all at Texas A&M and none of them had heard of the Gittins Index.
$endgroup$
– Jeff Hykin
Oct 22 '17 at 20:56










1 Answer
1






active

oldest

votes


















0












$begingroup$

Gittins indices are hard to compute. This paper offers a good overview of various algorithms:
http://www.ece.mcgill.ca/~amahaj1/projects/bandits/book/2013-bandit-computations.pdf






share|cite|improve this answer









$endgroup$













    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "69"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2473594%2fgittins-index-for-a-simple-example%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    0












    $begingroup$

    Gittins indices are hard to compute. This paper offers a good overview of various algorithms:
    http://www.ece.mcgill.ca/~amahaj1/projects/bandits/book/2013-bandit-computations.pdf






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      Gittins indices are hard to compute. This paper offers a good overview of various algorithms:
      http://www.ece.mcgill.ca/~amahaj1/projects/bandits/book/2013-bandit-computations.pdf






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        Gittins indices are hard to compute. This paper offers a good overview of various algorithms:
        http://www.ece.mcgill.ca/~amahaj1/projects/bandits/book/2013-bandit-computations.pdf






        share|cite|improve this answer









        $endgroup$



        Gittins indices are hard to compute. This paper offers a good overview of various algorithms:
        http://www.ece.mcgill.ca/~amahaj1/projects/bandits/book/2013-bandit-computations.pdf







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 7 at 4:10









        CarlyleanCarlylean

        11




        11






























            draft saved

            draft discarded




















































            Thanks for contributing an answer to Mathematics Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2473594%2fgittins-index-for-a-simple-example%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            Can a sorcerer learn a 5th-level spell early by creating spell slots using the Font of Magic feature?

            Does disintegrating a polymorphed enemy still kill it after the 2018 errata?

            A Topological Invariant for $pi_3(U(n))$