Gittins Index for a simple example












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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










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  • $begingroup$
    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






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share|cite|improve this question











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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
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$begingroup$

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









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    1 Answer
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    $begingroup$

    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












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        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

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