Module 2 – torch.nn: Building Neural Networks¶
"From mere tensors we forge SENTIENT NETWORKS! Witness the birth of computational consciousness!"
— Prof. Torchenstein
Welcome back, my diligent apprentices! Having mastered the fundamental art of tensor manipulation, you are now ready for the next phase of your transformation: breathing life into neural architectures! In this module, we shall wield torch.nn as both scalpel and forge, assembling layers and models worthy of legend! ⚡️🧪

What Awaits in This Module¶
In Module 2, we transition from raw tensor operations to the high-level building blocks that make PyTorch a joy to work with:
- Construct modular architectures using
nn.Moduleas your blueprint - Layer upon layer – from humble linear transformations to exotic normalization techniques
- Activate with purpose – ReLU, GELU, SiLU, and their mathematical rationale
- Encode position and meaning with embeddings and positional encodings
- Normalize like a pro – BatchNorm, LayerNorm, RMSNorm, and when to use each
- Master the training cycle – understanding loss functions, training vs. eval modes, and preparing data
Rebel Mission Checklist 📝¶
The nn.Module Blueprint¶
- Building Brains with nn.Module - Craft custom neural matter by overriding
__init__andforward - Franken-Stacking Layers - Bolt modules together with Sequential, ModuleList, and ModuleDict
- Preserving Your Monster's Memories - Save and resurrect model weights with state_dict necromancy
Linear Layers and Activations¶
- Linear Layers: The Vector Guillotine - Slice through dimensions, turning inputs into finely-chopped activations
- Activation Elixirs - Re-animate neurons with ReLU, GELU, SiLU, and other zesty potions
- Dropout: Neural Regularization - Make neurons forget just enough to generalize
Embeddings and Positional Encoding¶
- Embedding Layers: Secret Identity Chips - Embed discrete meanings within high-dimensional space
- Positional Encoding: Injecting Order - Imbue sequences with a sense of place so attention never loses its bearings
Normalization Techniques¶
- Normalization: Calming the Beast - Tame activations with BatchNorm and LayerNorm before they explode
- RMSNorm & Other Exotic Tonics - Sample contemporary concoctions for stable training
- Train vs. Eval: Split Personalities - Toggle modes and avoid awkward identity crises
Loss Functions and Training¶
- Loss Potions: Guiding Pain into Progress - Channel model errors into gradients that sharpen intelligence
- Preparing Sacrificial Inputs & Targets - Align logits and labels for maximum learning agony
- Reduction Rituals & Ignore Indices - Decipher reduction modes and skip unworthy samples
With these tools in hand, you will no longer be a mere tensor wrangler—you will be an architect of intelligence! The path ahead is electric with possibility. Steel your nerves, charge your GPUs, and prepare for computational glory!