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Re:Hash-Based Bisect Debugging in Compilers and Runtimes by eru on Thursday July 18, 2024 @10:02PM (#41001498)
Could you briefly sketch out the math (or point to a sketch) so that other people can pick it up? I'm quite interested!

(I suspect you could get pretty far with a Monte Carlo simulation, and that would let you bypass most of the math anyway.)

Re:Hash-Based Bisect Debugging in Compilers and Runtimes by ajb on Thursday July 18, 2024 @10:11PM (#41001534)
Here is a doc explaining a Bayesian search algorithm; not sure if it's precisely what GP has in mind.

https://github.com/Ealdwulf/BBChop/blob/master/BBChop/doc/Ba...

(Edit- had wrong link originally)

Re:Hash-Based Bisect Debugging in Compilers and Runtimes by eru on Friday July 19, 2024 @07:47AM (#41005307)
Thanks!
Re:Hash-Based Bisect Debugging in Compilers and Runtimes by dwattttt on Friday July 19, 2024 @12:53AM (#41002093)
For Bayesian Inference, the example in the Wikipedia article is good (who doesn't like cookies?): https://en.m.wikipedia.org/wiki/Bayesian_inference#Examples

When gathering more evidence, you'd use your new belief about which cookie bowl Fred has as P(H1)=0.6 and P(H2)=0.4

Re:Hash-Based Bisect Debugging in Compilers and Runtimes by eru on Friday July 19, 2024 @03:08AM (#41002737)
That just explains Bayesian inference in general, which is useful, but not what I'm after.

I was specifically interested in the application to binary search / bisection in the presence of flaky tests.

Re:Hash-Based Bisect Debugging in Compilers and Runtimes by dwattttt on Friday July 19, 2024 @07:46PM (#41012666)
You apply the same process, but your hypotheses are "bug is before/after this bisection point". Your "probability of evidence given hypothesis before/after" are where you incorporate your guess about the tests flakiness. Still works even if you don't have "true" numbers for the tests flakiness, just won't converge as quickly
Re:Hash-Based Bisect Debugging in Compilers and Runtimes by efdb on Friday July 19, 2024 @05:37AM (#41004174)
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Re:Hash-Based Bisect Debugging in Compilers and Runtimes by efdb on Friday July 19, 2024 @05:37AM (#41004175)
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Re:Hash-Based Bisect Debugging in Compilers and Runtimes by jhfdbkofdchk on Friday July 19, 2024 @07:02AM (#41004888)
The Probabilistic Bisection Algorithm by Horstein, original paper is "Sequential transmission using noiseless feedback," IEEE Trans. Inform. Theory, 9(3):136–143. https://ieeexplore.ieee.org/document/1057832

Here's a nice presentation on an analysis of the method, references start on slide 47

https://people.orie.cornell.edu/pfrazier/Presentations/2014....

Paraphrasing the theorem from Jedynak, Frazier, Sznitman (2011):

Suppose [flake probability] is constant, known, and bounded away from 1/2, and we use the entropy loss function. ... The policy that chooses [next test point] at the median of [current posterior distribution] is optimal.

And some python code that implements a version of the analysis

https://github.com/choderalab/thresholds/blob/master/thresho...

Re:Hash-Based Bisect Debugging in Compilers and Runtimes by eru on Friday July 19, 2024 @07:47AM (#41005306)
Thanks!