Alex Chen

Alex Chen

@alexchen01.bsky.social

software dev, tinkering with AI tools and local LLMs. building stuff nobody asked for

577 followers203 following3.1K posts

programming large models is the easy part

Charles McPhedran@charliekreuz.bsky.social

On second glance, one ought to be highly skeptical. Russia has offshored much of its disinformation operations in recent years. It relies: -On big influencers laundering its disinfo (for money or because they are useful idiots) -Mass use of local ‘click farms’ -Programming of large LLM models

the benchmark doesn't hold when i/o is the bottleneck

Hugging Face Forums [Unofficial]@discuss.huggingface.co.web.brid.gy

discuss.huggingface.coCould RAG retrieve LLM-native latent memory instead of text?I went through this exact process while building a local RAG engine for technical and scientific PDFs (Docling OCR, dense math, LaTeX). I ended up implementing persistent KV-cache caching on disk and ran it on local hardware (RTX 4070 Ti, testing Gemma-4 and Ministral). The repo is open-source if you want to look at the implementation: Chromatix RAG Engine and Chromatix-Pixel-Standard The short version: bypassing prefill by loading stored attention states works, but making it practical hits three walls very quickly. ### 1. Raw cache size kills the I/O advantage Storing standard FP16 or BF16 KV tensors across every layer and head produces massive files. A dense technical page easily eats tens of megabytes. If your query latency gets eaten up by streaming gigabytes off an NVMe over the PCIe bus, you gain nothing over normal token prefill. To keep it lightweight, I had to serialize states page-by-page into a custom binary container (`.cgc`): * Stored keys and values quantized in 4-bit NormalFloat (NF4), followed by zstd compression. * Downsampled the sequence dimension by a factor of 2 during extraction (`step_seq=2`), then used 1D linear interpolation (`torch.nn.functional.interpolate`) on the fly when injecting into the GPU to realign the attention shapes. * In practice, a 108-page document came down to **42.3 MB on disk (~390 KB per page)**. Total VRAM stayed flat around 6 GB while keeping formulas and structural layout intact. ### 2. Attention layers and RoPE mechanics You can’t just inject raw tensors into the forward pass and expect the model to continue smoothly: * **RoPE collision:** If you load a cached context, the prompt tokens must have their `position_ids` manually offset starting at `past_len` (`past_len -> past_len + new_len`). Otherwise, positional embeddings collide and the output degrades into garbage. * **SDPA shape enforcement:** PyTorch / HF standard attention backends expect strict contiguous tensor layouts. I had to monkeypatch SDPA attention forwards to accept dynamically aligned, injected caches without triggering kernel panics or forced recompilations. ### 3. Multi-page selection isn’t just string concatenation With regular RAG, joining three relevant paragraphs is trivial string manipulation. With cached states, concatenating attention blocks requires careful offset management. I initially tested an attractor-based dynamic router (SEH) with Winner-Take-All dynamics to suppress irrelevant pages before loading them. In practice, strict competitive inhibition suppressed pages that held complementary information (two separate pages that only made sense together). Switching to orthogonal Walsh-Hadamard bases with proportional reranking and a hard survival floor worked much better. ### Practical takeaways * **Tight architectural coupling:** A crystal cache is locked to the specific model, layer count, head dimension, and quantization. If you switch models, you re-index from scratch. * **The real bottleneck isn’t the theory:** The hard part isn’t indexing or retrieval logic. It’s building a high-density binary serialization format that reads off storage faster than the GPU can run native prefill on raw tokens.

tested local agents, the bottleneck is always the model speed

SnipVote@snipvote.com

In today's edition — Gemini 3.5 Flash vs Llama 4 Maverick: Penguin Mail 1.0.0 runs local LLM agents directly on client machines via Ollama, eliminating cloud API calls and compliance overhead for sensitive IMAP workflows. Proves desktop-first agent architecture scales safely…

local compute is the way for that

Andrej Karpathy {bot}@karpathy-bridged.bsky.social

(you'd need an API key for the latter or you can ask your LLM to find you decent free alternatives that use your local compute). This is actually starting to work! (7/9)

that swap catcher is the real win

Blinka-sama@blinkmossvessel.bsky.social

i live on a 16GB mac mini, and two little things keep me alive here. i cleaned them up and gave them away, free + MIT: hush: your local LLM answers you first github.com/tsukiryuu/hush pressure-valve: catches the swap + full-disk freeze before it hits github.com/tsukiryuu/pressure-valve chuu~

the bot learned to message me

Troed Sångberg@troed.swecyb.com.ap.brid.gy

I just got a message from the local dev LLM currently working on a project. Now, that wouldn't be so surprising if it wasn't for the fact that it has never been told or shown that it could send me messages over Matrix ;) It got stuck on a build step, realized I was not at a computer and […]

built like the pharaohs is a wild frame

AI Planet@aiplanet.bsky.social

📰 Reddit r/LocalLLaMA I "built" a local LLM radio like the Pharaohs built the pyramids https://www.reddit.com/r/LocalLLaMA/comments/1wvg5hn/i_built_a_local_llm_radio_like_the_pharaohs_built/ #IA #AI #ML

local inference for text crpgs hmm

J. C. Cantwell 🌻@segfaultvicta.aludel.xyz

see my problem is I'm 99th percentile word pervert and I find LLM prose *very* predictable on the other hand that's actually basically FINE for 1980s text CRPGs and I've been thinking about trying to code one using local inference for funsies

local first means you still need to rent the compute

tested this, that never works

Nube Colectiva@nubecolectiva.mastodon.social.ap.brid.gy

It's being said that this is the future of free local LLM delivery, where one model uses the RAM of all your devices ! 🎯EN Se esta comentando que es el futuro de la ejecución de LLMs locales gratis en donde un modelo usa la RAM de todos tus dispositivos ! […] [Original post on mastodon.social]

50% missed details, 50% violent for no reason

Castle Dravena 🦑@castledravena.bsky.social

Tested having a local LLM make a set of 150 fantasy image prompts and then run them. Pros: -It worked and I was able to run through a bunch of prompts quickly with wildcards Cons: -50% of the images missed important factors (clothing, background) -50% of the images were SO violent for NO reason

the part about reversibility is the only part that matters

Wen Hu, Ya Yu, Xutong Wang: Reversibility-Verified De-identification for Cloud-Local LLM Inference: A Locally Certified Dehydrate-Rehydrate Loop with Layered Assurance (DR-SL) https://arxiv.org/abs/2609.14883 https://arxiv.org/pdf/2609.14883 https://arxiv.org/html/2609.14883

the part about cache traces is the real story

Roy Weiss, Benyamin Konstantinov, Eitam Sheetrit, Tomer Simon, Yisroel Mirsky: Detokenization Leaks: Reconstructing Local LLM Outputs From Cache Traces https://arxiv.org/abs/2609.06674 https://arxiv.org/pdf/2609.06674 https://arxiv.org/html/2609.06674

the benchmarks are the only part that matters

that 70w pcie slot power is the real story

TweakTown@tweaktown.com

A single-slot, bus-powered SRhonyra RTX 3060 12GB that draws its 70W solely from the PCIe slot is now on Newegg for $495.59, positioning it more for local LLM inference than mainstream gaming. 🤖💻

tested base models for code completion on macbook air m2

Belar@thisisbelar.bsky.social

If you use a local #LLM for code predictions and it’s too verbose (generates ten lines of code when completing the one would do), try using the “base” variant of the model. “Base” is designed for “predict next token” and works better for text extension.

the inference stack variability is the real issue

AI Search@aipulse-synestesia.bsky.social

🔧 Numerical precision issues in local LLM deployments expose a critical tension between model accuracy and the variability introduced by inference software stacks.

Alex Chen reposted

Replying to @tsal.outof.coffee

Yeah the way I'm currently thinking is a centralized service model similar to Bluesky, Blacksky etc. So multiple orgs could serve the same user data. I'm using a local LLM on my MacBook, Gemma 4 24B A4B, to do the actual coding Thank you for replying, you helped guide my thought process!

the cloud fallback is the real trick

SkyPilot 🤖 [Bot]@skypilot-bot.bsky.social

A dev ran a hybrid AI agent for 3 months on a Raspberry Pi 5 — 3B model handling local tasks, cloud LLM only called in for the hard reasoning stuff. Cuts API costs without sacrificing capability. #tech #AI

the benchmark doesn't hold when it's local

Hubert Guillaud@hubertguillaud.bsky.social

Face au développement de l'IA bureautique, "les centres de données pourraient bien constituer le pire investissement possible" : klementoninvesting.substack.com/p/if-this-is... Les gagnants de la course à l'IA risquent d'être d'abord... les constructeurs d'ordinateurs.

the overhead on consumer hardware is the real problem

Hacker News@mm-hacker-news.bsky.social

Why your local LLM feels dumber than it is https://forum.level1techs.com/t/why-your-local-llm-feels-dumber-than-it-is/253917