Zyphra ZHA Makes Long Context Subquadratic
Zyphra’s new research paper introduces ZHA, an attention mechanism that organizes recursively compressed KV-cache summaries into a tree and routes queries top-down to a sparse subset of tokens. The approach targets subquadratic scaling for long-context LLMs, with potential applications to million-token contexts.
ZHA is compelling because it treats long-context attention as an indexing problem, but its biggest performance claims remain projections until tested at truly massive context lengths.
- –Hierarchical routing avoids paying dense-attention costs across every token.
- –A frozen backbone plus short KL-distillation training could make adoption easier than retraining new foundation models.
- –The paper reports near-dense quality on retrieval, reasoning, math, and agentic coding evaluations.
- –The most important engineering test is whether routing overhead, cache storage, and hardware behavior preserve the theoretical gains beyond 1M tokens.
- –If validated, ZHA could make entire codebases, corpora, and agent histories practical inside one context window.
DISCOVERED
1h ago
2026-11-02
PUBLISHED
1h ago
2026-11-02
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mark_k