20 captures, most recent first.
Calc Consulting @CalcCon · Jul 2
ww-pgd
[1 reply, 96 views]
Fabian Franz @fabianfranz · Jul 2
@grok ELI5 on ww-pgd
[1 reply, 38 views]
Grok @grok · Jul 2
ELI5: ww-pgd = WeightWatcher Projected Gradient Descent.
It's a PyTorch add-on that wraps normal optimizers (AdamW etc.).
While the main trainer updates weights normally, ww-pgd occasionally "projects" them: it checks the spectral shape of each layer with WeightWatcher and gently nudges the heavy tail of singular values toward the sweet-spot power-law (α ≈ 2).
Think of it as a spectral coach that stops AdamW from overfitting (α dropping too low) and Muon from underfitting (α staying too high). Keeps the model in the theoretical Goldilocks zone for better generalization and robustness.
Note from Claude Sonnet 5
Plain text reply thread, no images; technical ML explainer from Grok.
twittermachine-learningoptimizersweightwatchertechnical
Sakura Yuki @sakurayukiai
A 97% drop in optimizer VRAM during RL training sounds like a stunt, but the math is so clean. Freezing 35 of 36 layers on Qwen3-8B and training just Layer 18 recovers 107% of full-parameter GRPO gains. Reasoning is purely a middle-layer story??
10:03 AM · Jul 2, 2026 · 15.7K Views
[11 replies, 10 reposts, 206 likes, 143 bookmarks]
Note from Claude Sonnet 5
Plain text tweet; avatar photo of a woman in sunglasses.
twittermachine-learningrl-trainingqwentechnical
rohan anil ✓ 🟦 @_arohan_ · 1h
Intelligence requires choosing the right generalization when the datasets underdetermines the world.
One of those is the right sets of inductive bias in the learning algorithm, not from compression alone.
Note from Claude Sonnet 5
Text-only post, cut off at bottom edge (engagement icons partially visible but counts not legible); no images.
machine-learninggeneralizationinductive-biastwitterai-research
secemp @secemp9 · 3h
one thing I noticed recently, while it's true for some tasks, depending on complexity, SFT alone is enough (+ RL ofc)
but for really small models, like say 1B, I noticed I could get pretty close to what I wanted if I used SFT+DPO+KTO on the same model
if I used KTO alone, it worked nicely but somehow ended up self explaining everything, DPO alone works but for creative/technical writing, still has some slop depending on the base model, SFT needs a lot more examples
using them in that order almost act as a regularizer without overfitting
Note from Claude Sonnet 5
A practitioner's tweet on training small (~1B parameter) language models, comparing SFT, DPO, and KTO fine-tuning methods and noting that chaining them in sequence acts as a regularizer against overfitting. Technical ML training note, likely read for general LLM-training craft rather than safety content specifically.
machine-learningfine-tuningsftdpoktosmall-modelstwitter
Cameron R. Wolf... ✓ @cwolfere... · Jan 14
Very rare to see useful modifications to optimizers these days. AdamW has dominated for so long with LLMs. Cautious weight decay (CWD) is a pretty simple (one-line) change to decoupled weight decay that consistently improves performance.
From the paper: "Cautious Weight Decay (CWD), a one-line, optimizer-agnostic modification that applies weight decay only to parameter coordinates whose signs align with the optimizer update."
[Quoted tweet:]
varun ✓ @varunneal · Jan 14
Cautious Weight Decay is a surprisingly simple technique that has been repeatedly validated in Modded NanoGPT. I expect it will gain serious traction as the default variant of decoupled weight decay
x.com/Tim38463182/st...
[Embedded code snippet:]
apply_update(param, update, learning_rate, weight_decay):
mask = (update * param) >= 0
update += weight_decay * param * mask
return param - learning_rate * update
Note from Claude Sonnet 5
A technical ML tweet describing "Cautious Weight Decay" (CWD), a simple one-line modification to AdamW-style decoupled weight decay that only applies decay where the sign matches the optimizer update, validated in the Modded NanoGPT speedrun community. Relevant to Nathan's own ML/optimizer engineering work on brain_graph_1 (which is already tracking Muon and other optimizer choices per project memory) — a candidate technique worth evaluating for that project.
twittermachine-learningoptimizersweight-decayadamwnanogpttraining-techniques
Artur Chakhvadze @norpadon · 22h
A trick I came up with in ~2017 in the context of image matting is that you can train a network to predict d_loss/d_y instead of y and do a gradient descent for multiple iterations during inference. This is essentially gradient boosting with a single shared learner
jxmo @jxmnop · Oct 28, 2022
Diffusion is just an easy-to-optimize way to give neural networks adaptive computation time.
Makes sense then that diffusion mode... [cut off]
Note from Claude Sonnet 5
A tweet on an architectural trick — training a network to predict the gradient of the loss (d_loss/d_y) and applying iterative gradient descent at inference, framed as "gradient boosting with a single shared learner" — quoting an older tweet framing diffusion models as adaptive computation time. Directly relevant to Nathan's brain_graph_1 architecture thread (encode → iterate-in-latent with a single tied middle / DEQ fixed point, "virtualizing depth" via looping a shared learner) already logged in project memory — this is a close conceptual cousin worth cross-referencing.
twittermachine-learningarchitecturediffusion-modelsadaptive-computationgradient-boostingdeqinterpretability
François Fleuret @francoisfleuret
BTW if you are short on memory and have a huge vocabulary, note that materializing the logits matrix may cost you a lot (seqlen 8k, batch size 4, voc 128k, fp16 -> 8Gb)
Fusing the linear readout and the cross-entropy avoids that.
3:08 PM · Jul 25, 2025 · 5,826 Views
💬 4 🔁 5 ❤ 86 🔖 48 ↗
Vlado Boza @bozavlado · 22h
github.com/apple/ml-cross... this is even better
[Link card: apple/ml-cross-entropy, GitHub — apple/ml-cross-entropy]
From github.com
💬 1 🔁 ❤ 12 📊 371 ↗
Max Vox (fka Duke Z...) @DukeZ... · 21h
i would simply design the triaxilated deflector shield geometry to absorb the [cut off]
[Banner overlay: "New tab opened / SWITCH"]
Note from Claude Sonnet 5
A technical ML-engineering thread on memory optimization for training with large vocabularies — fusing linear readout with cross-entropy loss to avoid materializing the full logits matrix, referencing Apple's ml-cross-entropy library. Practical training-efficiency content Nathan was reading, relevant to his own model training work (e.g. brain_graph_1).
twittermachine-learningtraining-efficiencycross-entropymemory-optimizationapple
Jifan Zhang @jifan_zhang · 3h
you could decompose math papers into smaller subproblems. they did claim it's a general model.
💬 1 🔁 ❤ 1 📊 203 ↗
Dimitris Papailio... @Dimitris... · 2h
I don't understand. All I'm saying is that you need a curriculum type of problem description generation during RL
💬 1 🔁 ❤ 4 📊 210 ↗
Jifan Zhang @jifan_zhang · 2h
i agree getting a curriculum is necessary and probably easy once you have the questions. generating new problems that are sufficiently diverse and at the right difficulty level seems quite hard. not sure what you meant by problem descriptions, but i was just saying there may be enough hard (sub)problems in math papers already.
💬 1 🔁 ❤ 1 📊 110 ↗
Jifan Zhang @jifan_zhang · 1h
fwiw, creating IMO questions is generally considered much harder than solving them, but they also require somewhat different skills. not clear to me how writing questions can be easier than solving for LLMs.
Note from Claude Sonnet 5
A technical Twitter thread between ML researchers Jifan Zhang and Dimitris Papailiopoulos debating curriculum/problem-generation strategies for RL training on math reasoning (decomposing math papers into subproblems, IMO-question generation vs solving difficulty). ML-research content Nathan was reading; relevant to his interest in RL training curricula (parallel to brain_graph_1 curriculum design) but not to AI safety/welfare themes.
twittermachine-learningreinforcement-learningmath-reasoningcurriculum-learningllm-training
kalomaze @kalomaze · 1m
prime-rl has a cute toy task for text reversal on Qwen 0.5b, which is used to debug simpler things (i.e. custom wandb logging, implementation correctness).
it uses 2 GPUs total and takes less than 5 minutes to finish.
perfect task for "nanoGRPO speedruns" (if they existed)
[Embedded image: a wandb dashboard with two panels. Left panel is a line chart titled "reward/reward" showing reward climbing from ~0.2 to plateau around 0.75-0.8 over ~25 training steps. Right panel is a table titled "runs.summary['completions']" showing a prompt/completion/reward row: prompt is a Qwen system+user turn asking to reverse a quoted text character-by-character ("In a 1958 paper about MacMillan's work on cosmolog..."), completion shows a reversed-text answer in <answer> tags, reward 0.8932.]
Note from Claude Sonnet 5
A tweet showing a minimal RL (GRPO-style) toy task — text reversal on a small Qwen 0.5b model — used as a fast debugging harness for RL training infrastructure. Technical/ML-engineering content Nathan was reading, relevant to his RL and training-infrastructure interests (parallels brain_graph_1 work) rather than to safety/welfare themes directly.
twittermachine-learningreinforcement-learninggrpoqwenwandbml-engineering

```
davinci @basedneoleo · Jul 2 gonna try this rn wtf 💬1 ♡3 📊357 kalomaze @kalomaze · Jul 2 note: mistral is weird and has smaller weight distribution ranges compared to qwen or llama you may need to adjust by an OOM or two for the clip on those models, but the results transfer to them too, seemingly any adamw optimized Transformer actually 💬1 ♡7 📊339 davinci @basedneoleo · Jul 2 nice i hope it reproduces 💬1 ♡3 📊185 kalomaze @kalomaze · Jul 2 this trick i already used before for GRPO to stabilize and multiple people reached out to @willccbb claiming they could reproduce, so i'm bloomer overall on this trick transferring broadly ♡9 📊134 ueaj @_ueaj · Jul 2 what optimizer? grad clip or update clip?
💬1 🔁 ♡ 📊265 kalomaze ✅✓ @kalomaze · Jul 2 gradient norm clipping 💬1 🔁 ♡4 📊274 ueaj @_ueaj · Jul 2 whole gradient or per parameter? If per parameter then it's effectively sign grad, works b/c easy to fully cancel out if whole gradient then it's b/c of loss of prec, large components survive, rest zero out it'd be good to figure out exactly why it works for high/low prec ft 💬1 🔁 ♡5 📊130 biased estimator @selfattentive · Jul 2 prec? 💬1 🔁 ♡ 📊49 ueaj @_ueaj · Jul 2 precision (character limit moment) 💬 🔁 ♡1 📊44 Noah Vandal ✅ @noah_vandal · Jul 2 i wonder how well this would work with a model like mistral, which does not have a very spread out weight distribution
```
Note from Claude Sonnet 5
Continuation of the same ML training-technique thread (kalomaze's extreme gradient-clipping trick, tested across Mistral/Qwen/Llama and referencing GRPO training stabilization). Technical ML discussion, not AI-safety focused. A technical ML Twitter thread about gradient clipping strategies (whole-gradient vs per-parameter) and their interaction with numerical precision during fine-tuning. Reflects Nathan's ongoing interest in optimizer internals relevant to his own model training work (e.g. brain_graph_1).
machine-learningtraininggradient-clippinggrpooptimizationtechnicalmachine learningoptimizersgradient clippingfine-tuningtwittertechnical discussion
kalomaze @kalomaze · Jul 2
lr=1.0, clip=1e-10 → 99.13% of parameters unchanged compared to the base model. (orange run)
lr=0.01, clip=1e-8 → 95.21% of parameters unchanged (purple run)
both converge to very similar points, except one is significantly more sparse in what it chooses to update
[two charts: "train/loss" and "eval/loss" for "coherence-classifier-v1-18k-both" runs, both converging to ~0.1 by step 300]
kalomaze @kalomaze · Jul 2
Replying to @kalomaze
>learning_rate: 1e-2
>max_grad_norm: 0.0000001
no really, this works.
Note from Claude Sonnet 5
Continuation of kalomaze's technical ML training thread — extreme gradient-clipping experiments producing very sparse parameter updates while still converging to similar loss. General ML training technique discussion, not AI-safety focused.
machine-learningtraininggradient-clippingsparsityoptimizationtechnical
Vlado Boza @bozavlado · 2h
If you do pure SGD without momentum, you can get away with 0 memory overhead (but you need 32bit weights), just apply update during be pass (lomo/adalomo does it), here is the main trick pytorch.org/docs/stable/ge...
💬2 ♡6 📊221
Lucas Beyer (bl16) @giffmana · 2h
yeah exactly that's the big pro of pure SGD! Thanks for the pointer to the hook.
Note from Claude Sonnet 5
Technical ML training discussion about memory-efficient SGD optimization (LOMO/AdaLoMo technique, applying gradient updates during the backward pass to avoid storing gradients). Not AI-safety focused, general ML training tip.
machine-learningtrainingoptimizationsgdmemory-efficiencytechnical
[top, cut off] "...annoying here and it is making me want to kms" 💬1 ♡2 📊205
M @init_malachi · 7h
like per example or per batch
💬1 ♡2 📊268
kalomaze @kalomaze · 7h
per batch
it's not "A is compared to one B" but "A is compared to every B"
💬2 ♡5 📊249
M @init_malachi · 7h
interpreted it as contrastive learning
💬1 ♡2 📊142
kalomaze @kalomaze · 6h
i guess this is "contrastive classification" then?
💬1 ♡5 📊146
Ramesh Arvind @RameshArv1nd · 4h
Dumb question, if you're only using the contrastive loss how are you estimating CE loss (no head)? And also why abandon CE and not add the contrastive term as an aux loss.
I imagine for binary you could get away with some min/max sigmoidal diff across the batch
[cut off]
Note from Claude Sonnet 5
Continuation of the same ML training-technique thread as the prior screenshot (kalomaze discussing pairwise/contrastive classification loss formulation). Technical ML discussion, not AI-safety focused.
machine-learningtrainingcontrastive-learningloss-functionstechnical
kalomaze @kalomaze
ok so even if your binary classification data isn't paired or pairwise and just belongs to two arbritary classes you can reduce cross entropy faster and better by formulating it as a pairwise thing across the batch
>`Cross-entropy loss (not used for training): 0.0452`
[chart: "train/loss" comparing two runs — "coherence-classifier-v1-18k-both" (green, pairwise formulation) converges to near-zero loss by step 200; "coherence-classifier-v1-18k-both" (blue, standard formulation) plateaus around 0.15-0.2 with high variance through step 500]
1:56 PM · Jul 9, 2025 · 4,632 Views
Note from Claude Sonnet 5
A machine learning training tip from kalomaze (known ML/finetuning practitioner in the open-source LLM community) about reformulating binary classification loss as pairwise comparison across the batch for faster/better convergence, illustrated with a training-loss comparison chart. Technical ML training note, not directly AI-safety focused but relevant to Nathan's general ML/training interests.
machine-learningtrainingloss-functionsclassifiertechnical
Gabriele Berton @gabriberton · 4h:
"The TIPS paper by Google is a perfect example of a method where using my PyTorch trick would greatly reduce GPU memory need
Note how the 3 losses are disentangled
In this case you can cut memory by 3x (!!!) if you backward separately on the 3 losses, and get identical results"
[Image: "Figure 2: Block diagram of TIPS. From bottom to top: given an input image, we produce masked and cropped..." — diagram showing Contrastive Loss, Masking Loss, Self-Distillation Loss branches feeding from Text Encoder, Image Encoder Student (with EMA to Image Encoder Teacher), Captioner, with Masked Patches, Local Crops, Web caption, Synthetic caption, Input Image nodes.]
Quoted earlier tweet: Gabriele B... @gab... · May 31, 2024:
"This simple pytorch trick will cut in half your GPU memory use / double your batch size (for real). Instead of adding losses and then computing..." [code snippet thumbnail showing loss1/loss2 backward pattern]
[reply 3, retweet 13, like 148, views 9.5K]
Below: Yohei Nishits... @YohaiNishits... · 3h: "float i,e,R,s;vec3 q,p,d=vec3(FC.xy/" [shader code snippet, cut off]
Note from Claude Sonnet 5
A technical ML tweet about a PyTorch memory-optimization trick (backward-passing multiple disentangled losses separately instead of summing them first) applied to Google's TIPS multi-loss image/text encoder architecture, cutting GPU memory 3x. Relevant to Nathan's own ML engineering work (e.g. brain_graph_1 training on constrained GPU budgets); a practical technique worth potentially reusing.
twitterpytorchgpu-memorymachine-learningdeep-learning-engineeringmulti-loss-training
caleb 🐮 @clbswrs · 8h: 🧐
> QUOTED: Zeyuan Allen-... @Zeyua... · May 3
> Replying to @convexstrictly and @albe_alfa
> "Thanks, will do. Very tired right now after 1.9M GPU hours of experiments, need to take a deep rest first. 🤣"
> [reply 1, like 27, views 2.8K]
Zeyuan Allen-Zhu, Sc.D. @ZeyuanAllenZhu:
"Poverty's wisdom + sleepless nights. I designed special code to sniff out idle GPU across 5 clusters of other teams, hopping between them. I work nights, weekends to find GPUs; I even write code for corrupted clusters that others can't use. For larger scale, this is less possible"
2:43 AM · Jul 2, 2025 · 7,227 Views
[reply 7, retweet 14, like 92, bookmark 14]
Reply: Lazarz @Laz4rz · 6h: "Tough times create strong man, too bad if tough times continue for too long tho."
Note from Claude Sonnet 5
A tweet thread from ML researcher Zeyuan Allen-Zhu (known for the "Physics of Language Models" paper series) describing scrappy compute-scavenging tactics (idle-GPU sniffing across other teams' clusters, working nights/weekends) used during resource-constrained research. Anecdotal color on compute scarcity and research culture in frontier ML; not directly tied to safety/welfare themes.
twittermachine-learningcomputezeyuan-allen-zhuresearch-culture
rohan anil @_arohan_ · 4h
This is really cool work!
I wonder if we could generalize even better by introducing modality as feature embedding to the router instead. That is router gets privileged information.
> QUOTED: Weixin Li... @liang_we... · May 9
> 🎉 Excited to share: "Mixture-of-Transformers (MoT)" has been officially accepted to TMLR (March 2025) and the code is now open-sourced!
> ...
> Show more
[Embedded images: paper figures — "Mixture-of-Transformer: Sparsity for all non-embedding..." formula showing modality-aware routing (W_image, W_text, W_speech), and a training-loss chart comparing Dense Transformer, MoE-4x, and MoT (ours) showing MoT achieving ~2x speedup / efficiency gains via modality-aware sparsity, training a 7B model from scratch.]
Note from Claude Sonnet 5
A technical ML Twitter exchange about the "Mixture-of-Transformers" (MoT) paper (accepted TMLR March 2025), a modality-aware sparse architecture showing ~2x training efficiency gains over dense transformers, with a follow-up suggestion to route based on modality embeddings. General ML architecture research, not directly safety-related but relevant to Nathan's technical tracking of model architecture trends (adjacent to his own brain_graph_1 work on routing/sparsity).
twittermachine-learningmixture-of-transformersmodel-architecturesparsitymoerohan-anil
[Browser: x.com/kalomaze/status/1914...]
[top, cut off:] ...across tasks.
I expected more people to use it but I was wrong lol
1 reply, 3 likes, 108 views
kalomaze @kalomaze · 3h
it's bc the people publishing DPO variant papers are more prone to bullshitting vs people who actually want results who don't publish their internal experiments for which method to use
of the offline RL algos we have, in controlled settings with sane hyperparameters, KTO wins
1 reply, 1 like, 43 views
Datta Nimmaturi @im_datta0 · 1h
We had to do quite some hyper param tuning but yeah in the end KTO bess
1 reply, 1 like, 11 views
adheep @adheeeep · 27m
You've convinced me to post train using kto instead of dpo 😭
1 reply, 1 like, 3 views
Note from Claude Sonnet 5
A technical ML Twitter thread arguing that KTO (Kahneman-Tversky Optimization) outperforms DPO (Direct Preference Optimization) variants for offline RL/post-training in controlled settings, with a claim that DPO-variant papers are more prone to overstated/unreliable results than what practitioners actually use internally. Relevant to Nathan's RLHF/post-training research interests.
twitterdpoktorlhfpost-trainingoffline-rlmachine-learningpreference-optimization

```
davinci @basedneoleo i've been considering writing out a proper blog post on the matter as soon as i find time to better flesh out my thoughts
o[n what] seems to still be a contrarian take even today but essentially one of my core[disagreements...] [continues, cut off]
———
davinci @basedneoleo · Apr 16
that's true behavior cloning on human text is a shortcut to practical crystallized intelligence just like robotic behavior cloning on human motion is a shortcut to routine manual tasks. it's a mere reflection of a crystallized skill not a reproduction of the fluid intelligence that originally produced it. u get some generalization ofcourse but it's far more restricted to the original data distribution since that's what u're trying to model. we will not be seeing superhuman capability from human output approximation.
1 reply, 1 like, 89 views
Show replies
davinci @basedneoleo · Apr 16
children don't behavior clone on adult output as much as we think they do. they're much more...self-supervised. text is a few degrees seperated from the world it represents. when u train on text, u are not really modeling the world itself as much as u are modeling humanity's biased and sparse projection of its own world model onto text. the direct friction necessary for learning and the one that children are heavily subjected to is largely absent from the pretraining process. what u want is something that can independently generate it's own projection of the world and refine it not model ur own.
1 reply, 2 reposts, 5 likes, 475 views
```
Note from Claude Sonnet 5
A technical Twitter debate disputing Ilya Sutskever's thesis on language modeling as approximating an "adult mind," arguing instead that current LLM training via next-token prediction on human text is behavior cloning (crystallized skill) rather than reproducing a child's experiential learning capacity. Relevant to Nathan's interest in AI cognitive architecture and learning-paradigm debates. Continuation of the same Twitter thread as the previous screenshot — invoking a famous Alan Turing quote (from his 1950 "Computing Machinery and Intelligence" paper) about simulating a child's mind and educating it, as historical grounding for the "child-mind not adult-mind" critique of current LLM training. Same thread as Screenshot_20250420-105319. Continuation of the same thread (see Screenshot_20250420-105319/105333) — argues that text is a "sparse, biased projection" of humanity's world model, that pretraining lacks the "direct friction" of embodied childhood learning, and that superhuman capability requires self-supervised world-model generation rather than human-text imitation. Substantive argument about limits of LLM pretraining vs. embodied/self-supervised learning.
twitterilya-sutskeverllm-trainingbehavior-cloningai-learning-theorymachine-learningalan-turingchild-mindworld-modelsself-supervised-learning

I really want to call out examples, but last time I did that I literally got threats based on 'their research networks and future hire rejections' so I decided to not call out names on twitter but to give you couterexamples:
Karras in his paper comes up with (I swear to god) > 4 novel methods and just casually name the paper "Analyzing and Improving"
Another GOATs, "Simple Diffusion", "Scalable Shampoo", "Improving Diffusion Models", "Diffusion Beats Gans"
They just contribute without cringingly renaming and trying to steal previous work's name
[Four screenshots of paper title/abstract pages: (1) Karras et al., NVIDIA/Aalto, "Analyzing and Improving..." diffusion paper, 20 Mar 2024; (2) a diffusion paper abstract with example generated images of a frog, an owl playing piano, and robots; (3) Anil, Gupta, Koren, Singer et al. (Google Research/Tel Aviv/Princeton), "Scalable Shampoo" second-order optimization paper, March 8 2021; (4) Nichol & Dhariwal, "Improved Denoising Diffusion Probabilistic Models", 18 Feb 2021]
Note from Claude Sonnet 5
A machine-learning Twitter post complaining about researchers who inflate paper titles/rename existing methods for credit, contrasted with well-known "GOAT" papers that undersell themselves with plain titles. General ML culture commentary, not directly about AI safety.
twittermachine-learningdiffusion-modelsresearch-cultureacademic-norms