| 01 |
Linear & Logistic Regression |
Supervised |
Tabular Data |
Weighted linear hyperplane / Sigmoid log-odds optimization |
Maximum white-box interpretability, fast training, calibrated probabilities |
Cannot capture complex non-linear feature interactions without manual engineering |
| 02 |
Decision Trees (CART) |
Supervised |
Tabular Data |
Recursive binary splitting via Information Gain / Gini Impurity |
Human-readable flowchart logic; zero feature scaling required |
High variance; deep trees easily memorize training noise (overfitting) |
| 03 |
Random Forests |
Supervised |
Tabular Data |
Parallel bootstrap aggregating (Bagging) + random feature subspaces |
Resilient to outliers and overfitting; strong out-of-the-box tabular accuracy |
Slower inference and larger memory footprint than a single decision tree |
| 04 |
Gradient Boosting (XGBoost) |
Supervised |
Tabular Data |
Sequential additive trees trained on second-order loss gradients |
Benchmark accuracy leader on structured tabular classification & ranking |
Sensitive to hyperparameter tuning and extreme label noise |
| 05 |
Support Vector Machines (SVM) |
Supervised |
Tabular, CV, NLP |
Maximum-margin hyperplane + Kernel Trick ($K(x_i,x_j)$) |
Exceptional generalization in high-dimensional, small-sample regimes ($p \gg n$) |
$O(N^2)$–$O(N^3)$ kernel matrix scaling makes training slow on millions of rows |
| 06 |
K-Means Clustering |
Unsupervised |
Tabular, CV |
Iterative centroid assignment & mean update minimizing WCSS |
Linear $O(NKT)$ scalability; effortless unlabeled segmentation |
Requires pre-specifying $K$; assumes spherical, equally sized clusters |
| 07 |
Principal Component Analysis (PCA) |
Unsupervised |
Tabular, CV, NLP |
Spectral eigenvalue decomposition of feature covariance matrix |
Eliminates multicollinearity and compresses dimensions without labels |
Restricted to linear projections; orthogonal axes lose original feature meaning |
| 08 |
Convolutional Neural Nets (CNNs) |
Supervised |
Computer Vision |
Hierarchical 2D/3D spatial filter convolutions + residual connections |
Unmatched spatial inductive bias & low-latency edge vision inference |
Requires large labeled image datasets; limited global long-range context |
| 09 |
Encoder Transformers (BERT) |
Supervised / Self-Sup |
NLP |
Bidirectional multi-head self-attention + Masked Language Modeling |
Superior bidirectional context for text classification, NER, and embeddings |
Cannot natively generate open-ended multi-paragraph text |
| 10 |
Decoder Transformers (GPT LLMs) |
Unsup Pre-train + SFT |
NLP, Generative AI |
Causal masked self-attention predicting next token $P(w_t \mid w_{<t})$ |
Emergent zero/few-shot reasoning, code synthesis, and fluent generation |
High GPU memory/latency footprint; risk of ungrounded hallucinations |
| 11 |
Generative Adversarial Nets (GANs) |
Unsupervised / GenAI |
CV, Generative AI |
Adversarial minimax game between Generator $G$ and Discriminator $D$ |
Ultra-fast single-step image synthesis and high perceptual sharpness |
Prone to mode collapse, vanishing gradients, and unstable training dynamics |
| 12 |
Latent Diffusion (Stable Diffusion) |
Unsupervised / GenAI |
CV, Generative AI |
Iterative reverse denoising in compressed VAE latent space |
State-of-the-art visual diversity, mode coverage, and text-guided control |
Iterative sampling steps require higher inference compute than GANs |