In short, it made a C compiler (C11 Compliance & C23 Subset) from scratch for US$44.38, and ported 462K-LOC Fortran 90/2008 stellar astrophysics suite to 67K LOC of pure Rust library code (13 idiomatic Rust crates) for US$10.64: Idiomatic Julia code in AI generated code - #7 by Palli
It’s clear to me the model used is no longer the main thing, rather the harness or such tools used with. That said (despite the tool above used DeepSeek and GLM), I think this model is seriously intriguing and I would look into them:
MoVA: scaling attention with sparse experts
The core idea behind mixture-of-experts is to increase total model capacity while keeping the computation required for each token roughly fixed. ..
Our new architecture, MoVA—Mixture-of-Value Attention, extends this principle to attention. .. introducing sparsity there opens another dimension for scaling model capacity beyond the feed-forward network.
MoVA integrates expert routing into multi-head attention while remaining compatible with efficient techniques including FlashAttention, grouped-query attention, and sparse attention.
The result is K2 Horizon MoVA 36B-A4B: a model with 36 billion total parameters but approximately 4 billion active parameters per token. Under the same training conditions, it performs only slightly below the dense Horizon 32B model while requiring substantially fewer active parameters.
To quantify diversity at corpus scale, we developed a new compressor, Wzip, that combines a novel adaptive multi-sliding-window LZ77 algorithm with windowed Huffman coding. Wzip mitigates the rapid saturation observed with conventional gzip/zstd compression metrics as the number of documents grows, enabling more meaningful diversity measurements across large corpora.
Horizon 36B-A4B reaches nearly the performance of the dense 32B model while activating only approximately 4 billion parameters per token. Its efficiency comes from MoVA, our new sparse attention architecture, together with MoE feed-forward layers.
These two models serve as an important reference point for studying how dense and sparse architectures behave under similar training conditions.
Across reasoning, mathematics, coding and agentic tasks, K2 Horizon delivers top-tier performance in every size class—with the 0.9B, 3.7B and 7B models setting new state of the art at their respective scales.
..
Open source is much more than open weights. .. Every model in the fleet ships with its training data, recipe and evaluations. This is open science, and we believe it’s the best path forward for AI.
K2 Horizon includes key technology innovations:
- A unique “diffusion distillation” technique that generates blocks of tokens in parallel, which speeds model performance by roughly 3X without degrading response quality.
- A “mixture of value attention” architecture that improves reasoning without adding more computation.
- 36B (4B active): a new Mixture of Value Attention (MoVA) architecture that outperforms many larger models while activating only 4B parameters, which makes the model cost-effective for local hosting.
- 375B (23B active): K2 Horizon’s flagship model, built to compete with open-weight models on reasoning and agentic work, and ready for the enterprise.
DeepSeek V4.1 is also out seemingly very good. And of course OpenAI’s Astra 6, and Anthropic’s Fable 5.1, the competition is heating up, and I read OpenAI changed to a looped model (but not something I can confirm, like also suspected for Mythos/Fable), likely one reason it’s so good (and its “computer use”). Note, for Astra on the AGI benchmark ARC-AGI-3:
62.7%, $26.1K (Standard) · 98.6%, $17.3K (Provider Adapter)
vs. 100.0% at $2,986 for Tyco at ARC Prize - Community Leaderboard showing how much the harness/adapter can matter.