2D Random Walk Hitting Time












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Suppose there is a grid $[1,N]^2$. A person standing at some initial point $(x_0,y_0)$ walk randomly within the grid. At each location, he/she walks to a neighboring location with equal probability (e.g., for an interior point, the probability is $frac{1}{4}$; for a corner, it's $frac{1}{2}$.). Suppose there are $m$ absorbing barriers $B={(x_1,y_1),cdots,(x_m,y_m)}$ inside the grid. Once the person is on a barrier, the random walk process stops. I'd like to ask how to calculate the hitting probability and the expected number of steps for each barrier.



Edit: The problem can be transformed into a Markov chain. But the expected hitting time for each absorbing state is still not easy to calculate.










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    1












    $begingroup$


    Suppose there is a grid $[1,N]^2$. A person standing at some initial point $(x_0,y_0)$ walk randomly within the grid. At each location, he/she walks to a neighboring location with equal probability (e.g., for an interior point, the probability is $frac{1}{4}$; for a corner, it's $frac{1}{2}$.). Suppose there are $m$ absorbing barriers $B={(x_1,y_1),cdots,(x_m,y_m)}$ inside the grid. Once the person is on a barrier, the random walk process stops. I'd like to ask how to calculate the hitting probability and the expected number of steps for each barrier.



    Edit: The problem can be transformed into a Markov chain. But the expected hitting time for each absorbing state is still not easy to calculate.










    share|cite|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$


      Suppose there is a grid $[1,N]^2$. A person standing at some initial point $(x_0,y_0)$ walk randomly within the grid. At each location, he/she walks to a neighboring location with equal probability (e.g., for an interior point, the probability is $frac{1}{4}$; for a corner, it's $frac{1}{2}$.). Suppose there are $m$ absorbing barriers $B={(x_1,y_1),cdots,(x_m,y_m)}$ inside the grid. Once the person is on a barrier, the random walk process stops. I'd like to ask how to calculate the hitting probability and the expected number of steps for each barrier.



      Edit: The problem can be transformed into a Markov chain. But the expected hitting time for each absorbing state is still not easy to calculate.










      share|cite|improve this question











      $endgroup$




      Suppose there is a grid $[1,N]^2$. A person standing at some initial point $(x_0,y_0)$ walk randomly within the grid. At each location, he/she walks to a neighboring location with equal probability (e.g., for an interior point, the probability is $frac{1}{4}$; for a corner, it's $frac{1}{2}$.). Suppose there are $m$ absorbing barriers $B={(x_1,y_1),cdots,(x_m,y_m)}$ inside the grid. Once the person is on a barrier, the random walk process stops. I'd like to ask how to calculate the hitting probability and the expected number of steps for each barrier.



      Edit: The problem can be transformed into a Markov chain. But the expected hitting time for each absorbing state is still not easy to calculate.







      probability markov-chains random-walk






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 27 '18 at 12:21







      Hang Wu

















      asked Dec 26 '18 at 11:20









      Hang WuHang Wu

      428310




      428310






















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