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Fundamentals

Cross-Validation

Cross-validation is a resampling technique for estimating how well a model will generalize to unseen data.

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Fundamentals

Precision and Recall

Precision and recall are two complementary metrics for evaluating classifiers, especially when classes are imbalanced.

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Fundamentals

Double Descent Phenomenon

Double descent is the surprising observation that as a model gets bigger, test error first gets worse near the 'interpolation threshold' but then gets better…

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Fundamentals

Neural Tangent Kernel Theory

The Neural Tangent Kernel (NTK) is a mathematical tool showing that infinitely wide neural networks behave like a specific, fixed kernel method during…

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Fundamentals

Lottery Ticket Hypothesis

The Lottery Ticket Hypothesis says that inside a large, randomly initialized neural network hides a small subnetwork — a 'winning ticket' — that, trained…

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Fundamentals

Scaling Laws for Neural Networks

Scaling laws are empirical formulas showing that a neural network's loss falls predictably as you grow model size, dataset size, and compute.

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Fundamentals

Chinchilla Compute-Optimal Training

Chinchilla is a 2022 DeepMind finding that most large language models were badly undertrained: for a fixed compute budget you should scale parameters…

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Fundamentals

Grouped Reward Normalization in RLHF

Grouped reward normalization standardizes a model's rewards within a batch of responses to the same prompt, turning noisy scores into a stable training…

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Fundamentals

World Models and Learned Simulators

A world model is a neural network that learns to predict how an environment changes over time, letting an AI 'imagine' future outcomes before acting.

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Fundamentals

Length Normalization in Preference Optimization

Length normalization adjusts preference-tuning objectives so models stop winning approval just by writing longer answers.

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Fundamentals

Bradley-Terry Reward Modeling

The Bradley-Terry model is a century-old statistical method for turning pairwise comparisons (A beats B) into numeric scores.

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Fundamentals

Iterative DPO and Online Preference Tuning

Iterative DPO repeatedly aligns a language model to human or AI preferences by generating fresh responses, ranking them, and tuning on those new pairs each…

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