Feedforward Neural Networks, also called Multi-Layer Perceptrons (MLPs), are the most basic neural network
architecture. Information flows in one direction, from input to output, without loops.
- Best for: tabular data, basic classification and regression tasks.
- Structure: input layer → one or more hidden layers → output layer.
Convolutional Neural Networks are specialized for processing data with a grid-like structure, such as images.
They use convolutional layers to automatically learn local patterns (edges, textures, shapes).
- Best for: image, video, and spatial data.
- Key components: convolutional layers, pooling layers, fully connected layers.
Recurrent Neural Networks are designed for sequential data. They include recurrent connections that allow
information to persist over time steps.
- Best for: time series, text, and any ordered sequence.
- Challenge: basic RNNs can suffer from vanishing and exploding gradients.
Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) networks are advanced RNN variants that use
gating mechanisms to better capture long-term dependencies in sequences.
- Best for: long sequences, language modeling, machine translation, and speech recognition.
- Advantage: handle long-range dependencies better than vanilla RNNs.
Transformer models rely on attention mechanisms instead of recurrence or convolutions to process sequences.
They can model long-range dependencies in parallel, making training highly efficient on modern hardware.
- Best for: natural language processing, large language models, and many multi-modal tasks.
- Key concept: self-attention layers that weigh relationships between all elements in a sequence.
Autoencoders are neural networks that learn to compress data into a lower-dimensional representation (encoding)
and then reconstruct it (decoding). They are often used for representation learning and data compression.
- Best for: dimensionality reduction, anomaly detection, and denoising.
- Structure: encoder → latent space → decoder.
GANs consist of two networks: a generator that creates synthetic data and a discriminator that tries to
distinguish synthetic data from real data. They are trained in an adversarial setting.
- Best for: image generation, style transfer, data augmentation, and other generative tasks.
- Components: generator network, discriminator network, adversarial training loop.
Graph Neural Networks operate on graph-structured data, where entities are nodes and relationships are edges.
They aggregate information from neighboring nodes to learn powerful representations.
- Best for: social networks, molecular structures, recommendation systems, and knowledge graphs.
- Key operations: message passing, neighborhood aggregation.