[WanderPanda]

I applaud that you recently started providing the KL divergence plots that really help understand how different quantizations compare. But how well does this correlate with closed loop performance? How difficult/expensive would it be to run the quantizations on e.g. some agentic coding benchmarks?

[danielhanchen]

Hey! Sorry for not replying sooner - yes we'll keep publishing more KLD - sadly some are saying we are "optimizing" for KLD now since we posted so many haha - but the whole purpose of quantization is to match the BF16 logits as much as possible whilst reducing disk space (ie reduce KLD).

In general so this is funny and a quirk of quantization - sometimes 8bit, 4bit models do BETTER on downstream benchmarks (SWE Bench for eg), since sometimes rounding can actually somehow act as a "regularization" method (this is just my hunch).

So KLD isn't that expensive, since we leverage the trick of causal attention - since causal attention is lower triangular, we can do 1 forward pass on the enter text (say 2048 tokens), and you attain logits for the prediction for every token's position - so this is O(N^2).

However coding benchmarking require actual inference, and cannot use the causal attention trick, and it's best to run them 10 times since temperature = 1.0 is not deterministic - and take an average. We plan to maybe do something like https://marginlab.ai/trackers/claude-code/, which takes a random sample and does it over time.