Alan Royce Gabriel

Blog

Longer, more informal write-ups of the research on this site: the findings that don't fit neatly into a project page.

Fitting an epidemic to an electorate

We fitted eight models, from SIR and Lotka-Volterra to ARIMA, Neural ODEs, and PINNs, to fifty years of US presidential vote shares. The models that failed were as informative as the ones that fit, and the fitted numbers sketch an unflattering portrait of polarization.

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Putting prioritized replay's segment tree on a GPU

The sum tree inside Ape-X's replay buffer, ported to C and OpenACC: why the GPU-friendly batch update does asymptotically more work on purpose, the race condition that produced silently wrong probabilities, and honest crossover measurements.

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Q Bellman equation for a min-max adversarial game

What breaks in the ordinary Q-learning fixed point when an adversary picks half of every transition, and why the fix turns the greedy max into a small linear program over mixed strategies.

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Searching an infinite tree with a broken evaluator

Theory and measurements for tree search when the tree is infinite and the utility function is approximate: why depth rents out evaluator error at gamma^d, why the winner's curse fights back, and why A* tolerates optimism for free while noisy search cannot.

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