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What is the actual assignment here?

The README only gives numbers without any information on what you’re supposed to do or how you are rated.

Seems like they’re trying to hire nerds who know a lot about hardware or compiler optimizations. That will only get you so far. I guess hiring for creativity is a lot harder.

And before some smart aleck says you can be creative on these types of optimization problems: not in two hours, it’s far too risky vs regurgitating some standard set of tried and true algos.

Going through the assignment now. Man it’s really hard to pack the vectors right
This is a knowledge test of GPU architecture?
It shocks me that anyone supposedly good enough for anthropic would subject themselves to such a one sided waste of time.
Having recently learned more about SIMD, PTX and optimization techniques, this is a nice little challenge to learn even more.

As a take home assignment though I would have failed as I would have probably taken 2 hours to just sketch out ideas and more on my tablet while reading the code before even changing it.

The snarky writing of "if you beat our best solution, send us an email and MAYBE we think about interviewing you" is really something, innit?
I suspect this was released by Anthropic as a DDOS attack on other AI companies. I prompted 'how do we solve this challenge?' into gemini cli in a cloned repo and it's been running non-stop for 20 minutes :)
“If you optimize below 1487 cycles, beating Claude Opus 4.5's best performance at launch, email us at performance-recruiting@anthropic.com with your code (and ideally a resume) so we can be appropriately impressed and perhaps discuss interviewing.”
The writing was on the wall for about half a year (publicly) now. The oAI 2nd place at the atcoder world championship competition was the first one, and I remember it being dismissed at the time. Sakana also got 1st place in another atcoder competition a few weeks ago. Google also released a blog a few months back on gemini 2.5 netting them 1% reduction in training time on real-world tasks by optimising kernels.

If the models get a good feedback loop + easy (cheap) verification, they get to bang their tokens against the wall until they find a better solution.

I think this is the actual “bitter lesson”—the scalable solution (letting LLMs bang against the problem nonstop) will eventually far outperform human effort. There will come a point—whether sooner or later—where this’ll be the expected norm for handling such problems. I think the only question is whether there is any distinction between problems like this (clearly defined with a verifiable outcome) vs the space of all interesting computer programs. (At the moment I think there’s space between them. TBD.)
> This repo contains a version of Anthropic's original performance take-home, before Claude Opus 4.5 started doing better than humans given only 2 hours.

Was the screening format here that this problem was sent out, and candidates had to reply with a solution within 2 hours?

Or, are they just saying that the latest frontier coding models do better in 2 hours than human candidates have done in the past in multiple days?

I wonder if OpenAI follows suit.
I wonder if the Ai is doing anything novel? Or if it's like a brute force search of applying all types of existing optimizations that already exist and have been written about.
Having done a bunch of take home for big (and small) AI labs during interviews, this is the 2nd most interesting one I have seen so far.
>so we can be appropriately impressed and perhaps discuss interviewing.

Something comes across really badly here for me. Some weird mix of bragging, mocking, with a hint of aloof.

I feel these top end companies like the smell of their own farts and would be an insufferable place to work. This does nothing but reinforce it for some reason.

Naively tested a set of agents on this task.

Each ran the same spec headlessly in their native harness (one shot).

Results:

    Agent                        Cycles     Time
    ─────────────────────────────────────────────
    gpt-5-2                      2,124      16m
    claude-opus-4-5-20251101     4,973      1h 2m
    gpt-5-1-codex-max-xhigh      5,402      34m
    gpt-5-codex                  5,486      7m
    gpt-5-1-codex                12,453     8m
    gpt-5-2-codex                12,905     6m
    gpt-5-1-codex-mini           17,480     7m
    claude-sonnet-4-5-20250929   21,054     10m
    claude-haiku-4-5-20251001    147,734    9m
    gemini-3-pro-preview         147,734    3m
    gpt-5-2-codex-xhigh          147,734    25m
    gpt-5-2-xhigh                147,734    34m
Clearly none beat Anthropic's target, but gpt-5-2 did slightly better in much less time than "Claude Opus 4 after many hours in the test-time compute harness".
That Claude Opus 4.5 result of 4,973 is what you get if you just vectorize the reference kernel. In fact you should be under 4,900 doing that with very little effort (I tried doing this by hand yesterday).

The performance killer is the "random" access reads of the tree node data which the scalar implementation hides, together with the lack of load bandwidth, and to tackle that you'd have to rewrite the kernel to optimize the tree data loading and processing.

I consider myself rather smart and good at what I do. It's nice to have a look at problems like these once in a while, to remind myself of how little I know, and how much closer I am to the average than to the top.
Don’t stress, its very likely that this problem was vibe coded :) It’s insane how much better Claude Code is compared to alternatives lately.
Oh wow it’s by Tristan Hume, still remember you from EyeLike!
It's showcase more than being take home assignment. I couldnt understand what the task is ,only performance comparisons between their LLM
Oh, this was fun! If you like performance puzzles you should really do it. Actually I might go back and see if I can improve on it this weekend…
Interesting... Who would spend hours working for free for some company that promised only that they would invite you for a job interview. Maybe.