swh
227 posts

swh
@swhsiang
building humanoid | prev ML @CashApp Infra @salesforce Purdue ECE

Introducing GEN-0, our latest 10B+ foundation model for robots ⏱️ built on Harmonic Reasoning, new architecture that can think & act seamlessly 📈 strong scaling laws: more pretraining & model size = better 🌍 unprecedented corpus of 270,000+ hrs of dexterous data Read more 👇




Rollouts in the real world are slow and expensive. What if we could rollout trajectories entirely inside a world model (WM)? Introducing 🚀Ctrl-World🚀, a generative manipulation WM that can interact with advanced VLA policy in imagination. 🧵1/6


step-by-step LLM Engineering Projects each project = one concept learned the hard (i.e. real) way Tokenization & Embeddings > build byte-pair encoder + train your own subword vocab > write a “token visualizer” to map words/chunks to IDs > one-hot vs learned-embedding: plot cosine distances Positional Embeddings > classic sinusoidal vs learned vs RoPE vs ALiBi: demo all four > animate a toy sequence being “position-encoded” in 3D > ablate positions—watch attention collapse Self-Attention & Multihead Attention > hand-wire dot-product attention for one token > scale to multi-head, plot per-head weight heatmaps > mask out future tokens, verify causal property transformers, QKV, & stacking > stack the Attention implementations with LayerNorm and residuals → single-block transformer > generalize: n-block “mini-former” on toy data > dissect Q, K, V: swap them, break them, see what explodes Sampling Parameters: temp/top-k/top-p > code a sampler dashboard — interactively tune temp/k/p and sample outputs > plot entropy vs output diversity as you sweep params > nuke temp=0 (argmax): watch repetition KV Cache (Fast Inference) > record & reuse KV states; measure speedup vs no-cache > build a “cache hit/miss” visualizer for token streams > profile cache memory cost for long vs short sequences Long-Context Tricks: Infini-Attention / Sliding Window > implement sliding window attention; measure loss on long docs > benchmark “memory-efficient” (recompute, flash) variants > plot perplexity vs context length; find context collapse point Mixture of Experts (MoE) > code a 2-expert router layer; route tokens dynamically > plot expert utilization histograms over dataset > simulate sparse/dense swaps; measure FLOP savings Grouped Query Attention > convert your mini-former to grouped query layout > measure speed vs vanilla multi-head on large batch > ablate number of groups, plot latency Normalization & Activations > hand-implement LayerNorm, RMSNorm, SwiGLU, GELU > ablate each—what happens to train/test loss? > plot activation distributions layerwise Pretraining Objectives > train masked LM vs causal LM vs prefix LM on toy text > plot loss curves; compare which learns “English” faster > generate samples from each — note quirks Finetuning vs Instruction Tuning vs RLHF > fine-tune on a small custom dataset > instruction-tune by prepending tasks (“Summarize: ...”) > RLHF: hack a reward model, use PPO for 10 steps, plot reward Scaling Laws & Model Capacity > train tiny, small, medium models — plot loss vs size > benchmark wall-clock time, VRAM, throughput > extrapolate scaling curve — how “dumb” can you go? Quantization > code PTQ & QAT; export to GGUF/AWQ; plot accuracy drop Inference/Training Stacks: > port a model from HuggingFace to Deepspeed, vLLM, ExLlama > profile throughput, VRAM, latency across all three Synthetic Data > generate toy data, add noise, dedupe, create eval splits > visualize model learning curves on real vs synth each project = one core insight. build. plot. break. repeat. > don’t get stuck too long in theory > code, debug, ablate, even meme your graphs lol > finish each and post what you learned your future self will thank you later

Harvard and Stanford students tell me their professors don't understand AI and the courses are outdated. If elite schools can't keep up, the credential arms race is over. Self-learning is the only way now.














