Directional Ablation, and How Astra Fixed Qwen3.5-0.8B's Reasoning Loops

How an LLM edited 0.016% of Qwen3.5-0.8B’s weights to break its reasoning loops: directional ablation from the refusal-direction work, then pushed further with a strength α and 64 selected neurons per layer.

November 4, 2026 · 18 min · liqq

Fixing Softmax and Cross-Entropy: Two Numerical Pitfalls

Softmax Collapse and Softmax Cancellation: two floating-point pitfalls in Softmax and Cross-Entropy, and mathematically equivalent fixes.

October 25, 2026 · 3 min · liqq

Rotation Representations Part 1: Rotation Matrices, RoPE, and 6D/9D

Rotation matrices, complex numbers and RoPE, and the 6D and 9D rotation representations used in neural networks.

October 24, 2026 · 9 min · liqq

Why Training Loss Sawtooths Across Epochs

Why does training loss creep up within each epoch and drop at the next? Not the optimizer, but what the loss measures: the expected gap since a sample was last trained on follows a sawtooth, and it explains every sampling ablation.

October 15, 2026 · 14 min · liqq

From 1000 Steps to 1: Building Diffusion and Flow Models from Scratch

Clean, minimal PyTorch implementations of diffusion and flow models, from 1000-step DDPM to 1-step generators, on one backbone with one set of conventions.

October 9, 2026 · 37 min · liqq