Knowledge Base
Deep, connected write-ups for every topic — theory, math, code, and quizzes. 31 full articles · 80 topics indexed.
Foundations
Vectors, matrices, and the operations that underlie every model.
Derivatives, chain rule, and gradients — the language of learning.
Distributions, expectation, and reasoning under uncertainty.
Gradient descent, momentum, and the algorithms that fit models.
Array programming, broadcasting, and vectorized computation.
The Python you actually need under pressure — idioms, the standard library, and common traps.
Reasoning about time and space so you can spot the efficient solution — and prove it.
Pixels, convolution, filtering, and classical operators with OpenCV.
Advanced Math
Data Tooling
Engineering
Data Structures & Algorithms
Arrays, hashmaps, stacks, queues, heaps, trees, and graphs — and when each one wins.
Sorting, searching, recursion, and the algorithmic toolkit behind most interview problems.
Two pointers, sliding window, dynamic programming, and graph traversal — the patterns that unlock most problems.
ML Coding
The second coding round: implement a layer, a loss, and a full training loop in NumPy/PyTorch from a blank file.
Thinking in arrays — broadcasting, einsum, and turning loops into fast vectorized tensor code.
Deliberate, timed practice with the in-browser lab — build speed and correctness under interview pressure.
Fundamentals
Supervised learning, bias–variance, and the core ML workflow.
The multilayer perceptron: layers, activations, and forward passes.
Reverse-mode autodiff: how gradients flow through a network.
Tensors, autograd, nn.Module, and the training loop — the framework the labs actually run on.
Models
Decision trees, SVMs, k-NN, and linear/logistic regression — and when a simple model wins.
Turning raw data into features models can learn from — encoding, scaling, and leakage.
Clustering, PCA, and dimensionality reduction — finding structure without labels.
Bagging, random forests, and gradient boosting (XGBoost) — still the winners on tabular data.
Evaluation
Training Deep Nets
Architectures
Convolutions, pooling, and the architectures that see.
Recurrent networks, LSTMs, and sequence modeling — the pre-Transformer way to handle order.
Self-attention, multi-head attention, and the Transformer block.
Pretraining, fine-tuning, and reusing learned representations.
Hardware & Kernels
How GPUs actually run tensor math — threads, memory hierarchy, and where speed comes from.
fp16/bf16, loss scaling, and the numerical stability tricks that make big training runs survive.
Where the memory and the milliseconds go — activation memory, checkpointing, and profiling tools.
Data at Scale
Training at Scale
Splitting one training run across many GPUs and nodes — collectives, NCCL, and synchronization.
The three axes of splitting a model and batch across devices — and when to use each.
Sharding parameters, gradients, and optimizer states so trillion-parameter models fit.
Serving & Ops
KV caching, continuous batching, speculative decoding — serving tokens fast and cheap.
int8/int4, GPTQ/AWQ, distillation — shrinking models for cheaper, faster inference.
Experiment tracking, config management, checkpointing, and shipping models reliably.
The Big Picture
Text into Numbers
The Transformer
The one deceptively simple objective — predict the next token — that teaches a model grammar, facts, and reasoning.
How every token looks at every other token to decide what matters — the core idea of the Transformer.
Stacking attention with MLPs, residual connections, and normalization into the repeating block of every LLM.
Assemble a tiny working GPT end to end and train it to babble Shakespeare — the whole architecture in one file.
Pretraining at Scale
Where trillions of training tokens come from, how they're filtered and deduplicated, and why data quality is everything.
How performance improves predictably with parameters, data, and compute — and how to spend a training budget.
Running the objective across thousands of GPUs for months — optimizers, schedules, parallelism, and stability.
Post-training: Making it Helpful
Teaching the raw base model to follow instructions by fine-tuning on curated prompt–response demonstrations.
Learning a model of what humans prefer, so the assistant can be optimized toward helpful, honest, harmless answers.
Aligning the model to human preferences with reinforcement learning (PPO) or the simpler direct approach (DPO).
Making models honest and harmless at scale — RLAIF, Constitutional AI, and what 'alignment' really means.
Shipping the Model
Computer Vision
Detection & Segmentation
Advanced Vision
ViT, patch embeddings, and Swin — attention for images.
Keypoints, multi-object tracking, and dense motion estimation.
Contrastive and masked pretraining: SimCLR, MAE, DINOv2.
SAM, CLIP, Grounding DINO, and open-vocabulary perception.
Generative & 3D
Consuming Research
A repeatable method for tearing through a paper — the three-pass read, and how to extract the real idea.
Mapping a research area, tracing citations, and keeping up without drowning.
Turning a paper into working code — the single most valuable RE skill, and the messiest.
Doing Research
Framing a hypothesis, choosing baselines and controls, and running experiments you can trust.
Isolating what actually caused the improvement — the ablation table that makes a result believable.
Seeds, variance, error bars, and significance — telling a real effect from noise.
Why won't it train? Systematic debugging of loss curves, gradients, data, and shapes.