Likelihood

Now all we need is a likelihood function. We can use MakeLocationPmf to compute the likelihood of any value of x, given the coordinates of the opponent.

    def Likelihood(self, data, hypo):
        alpha, beta = hypo
        x = data
        pmf = MakeLocationPmf(alpha, beta, self.locations)
        like = pmf.Prob(x)
        return like

Again, alpha and beta are the hypothetical coordinates of the shooter, and x is the location of an observed spatter.

pmf contains the probability of each location, given the coordinates of the shooter. From this Pmf, we select the probability of the observed location.

And we’re done. To update the suite, we can use UpdateSet, which is inherited from Suite.

suite.UpdateSet([15, 16, 18, 21])

The result is a distribution that maps each (alpha, beta) pair to a posterior probability.

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