mirror of
https://github.com/MLSysBook/TinyTorch.git
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1025 lines
35 KiB
Python
1025 lines
35 KiB
Python
# ---
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# jupyter:
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# jupytext:
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# text_representation:
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# extension: .py
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# format_name: percent
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# format_version: '1.3'
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# jupytext_version: 1.17.1
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# ---
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# %% [markdown]
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"""
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# Networks - Neural Network Architectures
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Welcome to the Networks module! This is where we compose layers into complete neural network architectures.
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## Learning Goals
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- Understand networks as function composition: `f(x) = layer_n(...layer_2(layer_1(x)))`
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- Build the Sequential network architecture for composing layers
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- Create common network patterns like MLPs (Multi-Layer Perceptrons)
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- Visualize network architectures and understand their capabilities
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- Master forward pass inference through complete networks
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## Build → Use → Reflect
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1. **Build**: Sequential networks that compose layers into complete architectures
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2. **Use**: Create different network patterns and run inference
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3. **Reflect**: How architecture design affects network behavior and capability
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## What You'll Learn
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By the end of this module, you'll understand:
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- How simple layers combine to create complex behaviors
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- The fundamental Sequential architecture pattern
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- How to build MLPs with any number of layers
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- Different network architectures (shallow, deep, wide)
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- How neural networks approximate complex functions
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"""
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# %% nbgrader={"grade": false, "grade_id": "networks-imports", "locked": false, "schema_version": 3, "solution": false, "task": false}
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#| default_exp core.dense
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#| export
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import numpy as np
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import sys
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import os
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from typing import List, Union, Optional, Callable
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import matplotlib.pyplot as plt
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# Import all the building blocks we need - try package first, then local modules
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try:
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from tinytorch.core.tensor import Tensor
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from tinytorch.core.layers import Dense
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from tinytorch.core.activations import ReLU, Sigmoid, Tanh, Softmax
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except ImportError:
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# For development, import from local modules
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sys.path.append(os.path.join(os.path.dirname(__file__), '..', '01_tensor'))
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sys.path.append(os.path.join(os.path.dirname(__file__), '..', '02_activations'))
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sys.path.append(os.path.join(os.path.dirname(__file__), '..', '03_layers'))
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from tensor_dev import Tensor
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from activations_dev import ReLU, Sigmoid, Tanh, Softmax
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from layers_dev import Dense
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# %% nbgrader={"grade": false, "grade_id": "networks-setup", "locked": false, "schema_version": 3, "solution": false, "task": false}
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#| hide
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#| export
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def _should_show_plots():
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"""Check if we should show plots (disable during testing)"""
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# Check multiple conditions that indicate we're in test mode
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is_testing = (
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'pytest' in sys.modules or
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'test' in sys.argv or
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os.environ.get('PYTEST_CURRENT_TEST') is not None or
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any('test' in arg for arg in sys.argv) or
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any('pytest' in arg for arg in sys.argv) or
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'tito' in sys.argv or
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any('tito' in arg for arg in sys.argv) or
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os.environ.get('TITO_TESTING') is not None
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)
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# Show plots in development mode (when not in test mode)
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return not is_testing
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# %% nbgrader={"grade": false, "grade_id": "networks-welcome", "locked": false, "schema_version": 3, "solution": false, "task": false}
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print("🔥 TinyTorch Networks Module")
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print(f"NumPy version: {np.__version__}")
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print(f"Python version: {sys.version_info.major}.{sys.version_info.minor}")
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print("Ready to build neural network architectures!")
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# %% [markdown]
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"""
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## 📦 Where This Code Lives in the Final Package
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**Learning Side:** You work in `modules/source/04_networks/networks_dev.py`
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**Building Side:** Code exports to `tinytorch.core.networks`
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```python
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# Final package structure:
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from tinytorch.core.networks import Sequential, create_mlp # Network architectures!
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from tinytorch.core.layers import Dense, Conv2D # Building blocks
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from tinytorch.core.activations import ReLU, Sigmoid, Tanh # Nonlinearity
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from tinytorch.core.tensor import Tensor # Foundation
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```
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**Why this matters:**
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- **Learning:** Focused modules for deep understanding
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- **Production:** Proper organization like PyTorch's `torch.nn.Sequential`
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- **Consistency:** All network architectures live together in `core.networks`
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- **Integration:** Works seamlessly with layers, activations, and tensors
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"""
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# %% [markdown]
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"""
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## 🔧 DEVELOPMENT
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"""
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# %% [markdown]
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"""
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## Step 1: Understanding Neural Networks as Function Composition
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### What is a Neural Network?
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A neural network is simply **function composition** - chaining simple functions together to create complex behaviors:
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```
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f(x) = f_n(f_{n-1}(...f_2(f_1(x))))
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```
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### Real-World Analogy: Assembly Line
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Think of an assembly line in a factory:
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- **Input:** Raw materials (data)
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- **Stations:** Each worker (layer) transforms the product
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- **Output:** Final product (predictions)
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### The Power of Composition
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```python
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# Simple functions
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def add_one(x): return x + 1
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def multiply_two(x): return x * 2
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def square(x): return x * x
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# Composed function
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def complex_function(x):
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return square(multiply_two(add_one(x)))
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# This is what neural networks do!
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```
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### Why This Matters
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- **Universal Approximation:** MLPs can approximate any continuous function
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- **Hierarchical Learning:** Early layers learn simple features, later layers learn complex patterns
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- **Composability:** Mix and match layers to create custom architectures
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- **Scalability:** Add more layers or make them wider as needed
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### From Modules We've Built
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- **Tensors:** The data containers that flow through networks
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- **Activations:** The nonlinear transformations that enable complex behaviors
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- **Layers:** The building blocks that transform data
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Now let's build our first network architecture!
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"""
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# %% [markdown]
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"""
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## Step 2: Building the Sequential Network
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### What is Sequential?
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**Sequential** is the most fundamental network architecture - it applies layers in order:
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```
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Sequential([layer1, layer2, layer3])
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→ f(x) = layer3(layer2(layer1(x)))
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```
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### Why Sequential Matters
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- **Foundation:** Every neural network library has this pattern
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- **Simplicity:** Easy to understand and implement
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- **Flexibility:** Can compose any layers in any order
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- **Building Block:** Foundation for more complex architectures
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### The Sequential Pattern
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```python
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# PyTorch style
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model = nn.Sequential(
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nn.Linear(784, 128),
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nn.ReLU(),
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nn.Linear(128, 10)
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)
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# Our TinyTorch style
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model = Sequential([
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Dense(784, 128),
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ReLU(),
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Dense(128, 10)
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])
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```
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Let's implement this fundamental architecture!
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"""
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# %% nbgrader={"grade": false, "grade_id": "sequential-class", "locked": false, "schema_version": 3, "solution": true, "task": false}
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#| export
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class Sequential:
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"""
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Sequential Network: Composes layers in sequence
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The most fundamental network architecture.
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Applies layers in order: f(x) = layer_n(...layer_2(layer_1(x)))
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"""
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def __init__(self, layers: Optional[List] = None):
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"""
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Initialize Sequential network with layers.
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Args:
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layers: List of layers to compose in order (optional, defaults to empty list)
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TODO: Store the layers and implement forward pass
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APPROACH:
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1. Store the layers list as an instance variable
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2. Initialize empty list if no layers provided
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3. Prepare for forward pass implementation
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EXAMPLE:
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Sequential([Dense(3,4), ReLU(), Dense(4,2)])
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creates a 3-layer network: Dense → ReLU → Dense
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HINTS:
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- Use self.layers to store the layers
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- Handle empty initialization case
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"""
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### BEGIN SOLUTION
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self.layers = layers if layers is not None else []
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### END SOLUTION
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def forward(self, x: Tensor) -> Tensor:
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"""
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Forward pass through all layers in sequence.
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Args:
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x: Input tensor
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Returns:
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Output tensor after passing through all layers
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TODO: Implement sequential forward pass through all layers
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APPROACH:
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1. Start with the input tensor
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2. Apply each layer in sequence
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3. Each layer's output becomes the next layer's input
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4. Return the final output
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EXAMPLE:
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Input: Tensor([[1, 2, 3]])
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Layer1 (Dense): Tensor([[1.4, 2.8]])
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Layer2 (ReLU): Tensor([[1.4, 2.8]])
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Layer3 (Dense): Tensor([[0.7]])
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Output: Tensor([[0.7]])
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HINTS:
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- Use a for loop: for layer in self.layers:
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- Apply each layer: x = layer(x)
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- The output of one layer becomes input to the next
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- Return the final result
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"""
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### BEGIN SOLUTION
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# Apply each layer in sequence
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for layer in self.layers:
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x = layer(x)
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return x
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### END SOLUTION
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def __call__(self, x: Tensor) -> Tensor:
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"""Make the network callable: sequential(x) instead of sequential.forward(x)"""
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return self.forward(x)
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def add(self, layer):
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"""Add a layer to the network."""
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self.layers.append(layer)
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# %% [markdown]
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"""
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### 🧪 Unit Test: Sequential Network
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Let's test your Sequential network implementation! This is the foundation of all neural network architectures.
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**This is a unit test** - it tests one specific class (Sequential network) in isolation.
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"""
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# %% nbgrader={"grade": true, "grade_id": "test-sequential-immediate", "locked": true, "points": 10, "schema_version": 3, "solution": false, "task": false}
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# Test Sequential network immediately after implementation
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print("🔬 Unit Test: Sequential Network...")
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# Create a simple 2-layer network: 3 → 4 → 2
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try:
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network = Sequential([
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Dense(input_size=3, output_size=4),
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ReLU(),
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Dense(input_size=4, output_size=2),
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Sigmoid()
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])
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print(f"Network created with {len(network.layers)} layers")
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print("✅ Sequential network creation successful")
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# Test with sample data
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x = Tensor([[1.0, 2.0, 3.0]])
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print(f"Input: {x}")
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# Forward pass
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y = network(x)
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print(f"Output: {y}")
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print(f"Output shape: {y.shape}")
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# Verify the network works
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assert y.shape == (1, 2), f"Expected shape (1, 2), got {y.shape}"
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print("✅ Sequential network produces correct output shape")
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# Test that sigmoid output is in valid range
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assert np.all(y.data >= 0) and np.all(y.data <= 1), "Sigmoid output should be between 0 and 1"
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print("✅ Sequential network output is in valid range")
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# Test that layers are stored correctly
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assert len(network.layers) == 4, f"Expected 4 layers, got {len(network.layers)}"
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print("✅ Sequential network stores layers correctly")
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# Test batch processing
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x_batch = Tensor([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]])
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y_batch = network(x_batch)
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assert y_batch.shape == (2, 2), f"Expected batch shape (2, 2), got {y_batch.shape}"
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print("✅ Sequential network handles batch processing")
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except Exception as e:
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print(f"❌ Sequential network test failed: {e}")
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raise
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# Show the network architecture
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print("🎯 Sequential network behavior:")
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print(" Applies layers in sequence: f(g(h(x)))")
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print(" Input flows through each layer in order")
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print(" Output of layer i becomes input of layer i+1")
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print("📈 Progress: Sequential network ✓")
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# %% [markdown]
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"""
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## Step 3: Building Multi-Layer Perceptrons (MLPs)
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### What is an MLP?
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A **Multi-Layer Perceptron** is the classic neural network architecture:
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```
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Input → Dense → Activation → Dense → Activation → ... → Dense → Output
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```
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### Why MLPs are Important
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- **Universal approximation**: Can approximate any continuous function
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- **Foundation**: Basis for understanding all neural networks
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- **Versatile**: Works for classification, regression, and more
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- **Simple**: Easy to understand and implement
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### MLP Architecture Pattern
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```
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create_mlp(3, [4, 2], 1) creates:
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Dense(3→4) → ReLU → Dense(4→2) → ReLU → Dense(2→1) → Sigmoid
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```
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### Real-World Applications
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- **Tabular data**: Customer analytics, financial modeling
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- **Feature learning**: Learning representations from raw data
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- **Classification**: Spam detection, medical diagnosis
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- **Regression**: Price prediction, time series forecasting
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### The MLP Factory Pattern
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Instead of manually creating each layer, we'll build a function that creates MLPs automatically!
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"""
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# %% nbgrader={"grade": false, "grade_id": "create-mlp", "locked": false, "schema_version": 3, "solution": true, "task": false}
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#| export
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def create_mlp(input_size: int, hidden_sizes: List[int], output_size: int,
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activation=ReLU, output_activation=Sigmoid) -> Sequential:
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"""
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Create a Multi-Layer Perceptron (MLP) network.
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Args:
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input_size: Number of input features
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hidden_sizes: List of hidden layer sizes
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output_size: Number of output features
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activation: Activation function for hidden layers (default: ReLU)
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output_activation: Activation function for output layer (default: Sigmoid)
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Returns:
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Sequential network with MLP architecture
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TODO: Implement MLP creation with alternating Dense and activation layers.
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APPROACH:
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1. Start with an empty list of layers
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2. Add layers in this pattern:
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- Dense(input_size → first_hidden_size)
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- Activation()
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- Dense(first_hidden_size → second_hidden_size)
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- Activation()
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- ...
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- Dense(last_hidden_size → output_size)
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- Output_activation()
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3. Return Sequential(layers)
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EXAMPLE:
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create_mlp(3, [4, 2], 1) creates:
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Dense(3→4) → ReLU → Dense(4→2) → ReLU → Dense(2→1) → Sigmoid
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HINTS:
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- Start with layers = []
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- Track current_size starting with input_size
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- For each hidden_size: add Dense(current_size, hidden_size), then activation
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- Finally add Dense(last_hidden_size, output_size), then output_activation
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- Return Sequential(layers)
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"""
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layers = []
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current_size = input_size
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# Add hidden layers with activations
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for hidden_size in hidden_sizes:
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layers.append(Dense(current_size, hidden_size))
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layers.append(activation())
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current_size = hidden_size
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# Add output layer with output activation
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layers.append(Dense(current_size, output_size))
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layers.append(output_activation())
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return Sequential(layers)
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# %% [markdown]
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"""
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### 🧪 Unit Test: MLP Creation
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Let's test your MLP creation function! This builds complete neural networks with a single function call.
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**This is a unit test** - it tests one specific function (create_mlp) in isolation.
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"""
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# %% nbgrader={"grade": true, "grade_id": "test-mlp-immediate", "locked": true, "points": 10, "schema_version": 3, "solution": false, "task": false}
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# Test MLP creation immediately after implementation
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print("🔬 Unit Test: MLP Creation...")
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# Create a simple MLP: 3 → 4 → 2 → 1
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try:
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mlp = create_mlp(input_size=3, hidden_sizes=[4, 2], output_size=1)
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print(f"MLP created with {len(mlp.layers)} layers")
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print("✅ MLP creation successful")
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# Test the structure - should have 6 layers: Dense, ReLU, Dense, ReLU, Dense, Sigmoid
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expected_layers = 6 # 3 Dense + 2 ReLU + 1 Sigmoid
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assert len(mlp.layers) == expected_layers, f"Expected {expected_layers} layers, got {len(mlp.layers)}"
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print("✅ MLP has correct number of layers")
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# Test layer types
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layer_types = [type(layer).__name__ for layer in mlp.layers]
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expected_pattern = ['Dense', 'ReLU', 'Dense', 'ReLU', 'Dense', 'Sigmoid']
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assert layer_types == expected_pattern, f"Expected pattern {expected_pattern}, got {layer_types}"
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print("✅ MLP follows correct layer pattern")
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# Test with sample data
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x = Tensor([[1.0, 2.0, 3.0]])
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y = mlp(x)
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print(f"MLP input: {x}")
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print(f"MLP output: {y}")
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print(f"MLP output shape: {y.shape}")
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# Verify the output
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assert y.shape == (1, 1), f"Expected shape (1, 1), got {y.shape}"
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print("✅ MLP produces correct output shape")
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# Test that sigmoid output is in valid range
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assert np.all(y.data >= 0) and np.all(y.data <= 1), "Sigmoid output should be between 0 and 1"
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print("✅ MLP output is in valid range")
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except Exception as e:
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print(f"❌ MLP creation test failed: {e}")
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raise
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# Test different architectures
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try:
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# Test shallow network
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shallow_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1)
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assert len(shallow_net.layers) == 4, f"Shallow network should have 4 layers, got {len(shallow_net.layers)}"
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# Test deep network
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deep_net = create_mlp(input_size=3, hidden_sizes=[4, 4, 4], output_size=1)
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assert len(deep_net.layers) == 8, f"Deep network should have 8 layers, got {len(deep_net.layers)}"
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# Test wide network
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wide_net = create_mlp(input_size=3, hidden_sizes=[10], output_size=1)
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assert len(wide_net.layers) == 4, f"Wide network should have 4 layers, got {len(wide_net.layers)}"
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print("✅ Different MLP architectures work correctly")
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except Exception as e:
|
|
print(f"❌ MLP architecture test failed: {e}")
|
|
raise
|
|
|
|
# Show the MLP pattern
|
|
print("🎯 MLP creation pattern:")
|
|
print(" Input → Dense → Activation → Dense → Activation → ... → Dense → Output_Activation")
|
|
print(" Automatically creates the complete architecture")
|
|
print(" Handles any number of hidden layers")
|
|
print("📈 Progress: Sequential network ✓, MLP creation ✓")
|
|
|
|
# %% [markdown]
|
|
"""
|
|
## Step 4: Understanding Network Architectures
|
|
|
|
### Architecture Patterns
|
|
Different network architectures solve different problems:
|
|
|
|
#### **Shallow vs Deep Networks**
|
|
```python
|
|
# Shallow: 1 hidden layer
|
|
shallow = create_mlp(10, [20], 1)
|
|
|
|
# Deep: Many hidden layers
|
|
deep = create_mlp(10, [20, 20, 20], 1)
|
|
```
|
|
|
|
#### **Narrow vs Wide Networks**
|
|
```python
|
|
# Narrow: Few neurons per layer
|
|
narrow = create_mlp(10, [5, 5], 1)
|
|
|
|
# Wide: Many neurons per layer
|
|
wide = create_mlp(10, [50], 1)
|
|
```
|
|
|
|
### Why Architecture Matters
|
|
- **Capacity:** More parameters can learn more complex patterns
|
|
- **Depth:** Enables hierarchical feature learning
|
|
- **Width:** Allows parallel processing of features
|
|
- **Efficiency:** Balance between performance and computation
|
|
|
|
### Different Activation Functions
|
|
```python
|
|
# ReLU networks (most common)
|
|
relu_net = create_mlp(10, [20], 1, activation=ReLU)
|
|
|
|
# Tanh networks (centered around 0)
|
|
tanh_net = create_mlp(10, [20], 1, activation=Tanh)
|
|
|
|
# Multi-class classification
|
|
classifier = create_mlp(10, [20], 3, output_activation=Softmax)
|
|
```
|
|
|
|
Let's test different architectures!
|
|
"""
|
|
|
|
# %% [markdown]
|
|
"""
|
|
### 🧪 Unit Test: Architecture Variations
|
|
|
|
Let's test different network architectures to understand their behavior.
|
|
|
|
**This is a unit test** - it tests architectural variations in isolation.
|
|
"""
|
|
|
|
# %% nbgrader={"grade": true, "grade_id": "test-architectures", "locked": true, "points": 10, "schema_version": 3, "solution": false, "task": false}
|
|
def plot_network_architectures():
|
|
"""Visualize different network architectures."""
|
|
if not _should_show_plots():
|
|
return
|
|
|
|
# Create different architectures
|
|
relu_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1, activation=ReLU)
|
|
tanh_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1, activation=Tanh)
|
|
classifier = create_mlp(input_size=3, hidden_sizes=[4], output_size=3, output_activation=Softmax)
|
|
|
|
# Create input data
|
|
x = Tensor([[1.0, 2.0, 3.0]])
|
|
|
|
# Get outputs
|
|
y_relu = relu_net(x)
|
|
y_tanh = tanh_net(x)
|
|
y_multi = classifier(x)
|
|
|
|
# Plot the results
|
|
fig, axs = plt.subplots(1, 3, figsize=(15, 4))
|
|
|
|
axs[0].set_title("ReLU Network Output")
|
|
axs[0].bar(['Output'], [y_relu.data[0][0]], color='skyblue')
|
|
|
|
axs[1].set_title("Tanh Network Output")
|
|
axs[1].bar(['Output'], [y_tanh.data[0][0]], color='salmon')
|
|
|
|
axs[2].set_title("Softmax Classifier Output")
|
|
axs[2].bar([f"Class {i}" for i in range(3)], y_multi.data[0], color='lightgreen')
|
|
|
|
plt.tight_layout()
|
|
plt.show()
|
|
|
|
def test_unit_network_architectures():
|
|
"""Unit test for different network architectures."""
|
|
# Test different architectures
|
|
print("🔬 Unit Test: Network Architecture Variations...")
|
|
|
|
try:
|
|
# Test different activation functions
|
|
relu_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1, activation=ReLU)
|
|
tanh_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1, activation=Tanh)
|
|
|
|
# Test different output activations
|
|
classifier = create_mlp(input_size=3, hidden_sizes=[4], output_size=3, output_activation=Softmax)
|
|
|
|
# Test with sample data
|
|
x = Tensor([[1.0, 2.0, 3.0]])
|
|
|
|
# Test ReLU network
|
|
y_relu = relu_net(x)
|
|
assert y_relu.shape == (1, 1), "ReLU network should work"
|
|
print("✅ ReLU network works correctly")
|
|
|
|
# Test Tanh network
|
|
y_tanh = tanh_net(x)
|
|
assert y_tanh.shape == (1, 1), "Tanh network should work"
|
|
print("✅ Tanh network works correctly")
|
|
|
|
# Test multi-class classifier
|
|
y_multi = classifier(x)
|
|
assert y_multi.shape == (1, 3), "Multi-class classifier should work"
|
|
|
|
# Check softmax properties
|
|
assert abs(np.sum(y_multi.data) - 1.0) < 1e-6, "Softmax outputs should sum to 1"
|
|
print("✅ Multi-class classifier with Softmax works correctly")
|
|
|
|
# Test different architectures
|
|
shallow = create_mlp(input_size=4, hidden_sizes=[5], output_size=1)
|
|
deep = create_mlp(input_size=4, hidden_sizes=[5, 5, 5], output_size=1)
|
|
wide = create_mlp(input_size=4, hidden_sizes=[20], output_size=1)
|
|
|
|
x_test = Tensor([[1.0, 2.0, 3.0, 4.0]])
|
|
|
|
# Test all architectures
|
|
for name, net in [("Shallow", shallow), ("Deep", deep), ("Wide", wide)]:
|
|
y = net(x_test)
|
|
assert y.shape == (1, 1), f"{name} network should produce correct shape"
|
|
print(f"✅ {name} network works correctly")
|
|
|
|
print("✅ All network architectures work correctly")
|
|
|
|
except Exception as e:
|
|
print(f"❌ Architecture test failed: {e}")
|
|
raise
|
|
|
|
print("🎯 Architecture insights:")
|
|
print(" Different activations create different behaviors")
|
|
print(" Softmax enables multi-class classification")
|
|
print(" Architecture affects network capacity and learning")
|
|
print("📈 Progress: Sequential ✓, MLP creation ✓, Architecture variations ✓")
|
|
|
|
# %% [markdown]
|
|
"""
|
|
### 📊 Visualization Demo: Network Architectures
|
|
|
|
Let's visualize the different network architectures for educational purposes:
|
|
"""
|
|
|
|
# %%
|
|
# Demo visualization - only run in interactive mode, not during tests
|
|
if __name__ == "__main__":
|
|
# Generate network architecture visualization (only in interactive mode)
|
|
if _should_show_plots():
|
|
plot_network_architectures()
|
|
print("📊 Network architecture visualization complete!")
|
|
else:
|
|
print("📊 Plots disabled during testing")
|
|
|
|
# %% [markdown]
|
|
"""
|
|
## Step 5: Comprehensive Test - Complete Network Applications
|
|
|
|
### Real-World Network Applications
|
|
Let's test our networks on realistic scenarios:
|
|
|
|
#### **Classification Problem**
|
|
```python
|
|
# 4 features → 2 classes (binary classification)
|
|
classifier = create_mlp(4, [8, 4], 2, output_activation=Softmax)
|
|
```
|
|
|
|
#### **Regression Problem**
|
|
```python
|
|
# 3 features → 1 continuous output
|
|
regressor = create_mlp(3, [10, 5], 1, output_activation=lambda: Dense(0, 0)) # Linear output
|
|
```
|
|
|
|
#### **Deep Learning Pattern**
|
|
```python
|
|
# Complex feature learning
|
|
deep_net = create_mlp(10, [64, 32, 16], 1)
|
|
```
|
|
|
|
This comprehensive test ensures our networks work for real ML applications!
|
|
"""
|
|
|
|
# %% nbgrader={"grade": true, "grade_id": "test-integration", "locked": true, "points": 15, "schema_version": 3, "solution": false, "task": false}
|
|
# Comprehensive test - complete network applications
|
|
print("🔬 Comprehensive Test: Complete Network Applications...")
|
|
|
|
try:
|
|
# Test 1: Multi-class Classification (Iris-like dataset)
|
|
print("\n1. Multi-class Classification Test:")
|
|
iris_classifier = create_mlp(input_size=4, hidden_sizes=[8, 6], output_size=3, output_activation=Softmax)
|
|
|
|
# Simulate iris features: [sepal_length, sepal_width, petal_length, petal_width]
|
|
iris_samples = Tensor([
|
|
[5.1, 3.5, 1.4, 0.2], # Setosa
|
|
[7.0, 3.2, 4.7, 1.4], # Versicolor
|
|
[6.3, 3.3, 6.0, 2.5] # Virginica
|
|
])
|
|
|
|
iris_predictions = iris_classifier(iris_samples)
|
|
assert iris_predictions.shape == (3, 3), "Iris classifier should output 3 classes for 3 samples"
|
|
|
|
# Check softmax properties
|
|
row_sums = np.sum(iris_predictions.data, axis=1)
|
|
assert np.allclose(row_sums, 1.0), "Each prediction should sum to 1"
|
|
print("✅ Multi-class classification works correctly")
|
|
|
|
# Test 2: Regression Task (Housing prices)
|
|
print("\n2. Regression Task Test:")
|
|
# Create a regressor without final activation (linear output)
|
|
class Identity:
|
|
def __call__(self, x): return x
|
|
|
|
housing_regressor = create_mlp(input_size=3, hidden_sizes=[10, 5], output_size=1, output_activation=Identity)
|
|
|
|
# Simulate housing features: [size, bedrooms, location_score]
|
|
housing_samples = Tensor([
|
|
[2000, 3, 8.5], # Large house, good location
|
|
[1200, 2, 6.0], # Medium house, ok location
|
|
[800, 1, 4.0] # Small house, poor location
|
|
])
|
|
|
|
housing_predictions = housing_regressor(housing_samples)
|
|
assert housing_predictions.shape == (3, 1), "Housing regressor should output 1 value per sample"
|
|
print("✅ Regression task works correctly")
|
|
|
|
# Test 3: Deep Network Performance
|
|
print("\n3. Deep Network Test:")
|
|
deep_network = create_mlp(input_size=10, hidden_sizes=[20, 15, 10, 5], output_size=1)
|
|
|
|
# Test with realistic batch size
|
|
batch_data = Tensor(np.random.randn(32, 10)) # 32 samples, 10 features
|
|
deep_predictions = deep_network(batch_data)
|
|
|
|
assert deep_predictions.shape == (32, 1), "Deep network should handle batch processing"
|
|
assert not np.any(np.isnan(deep_predictions.data)), "Deep network should not produce NaN"
|
|
print("✅ Deep network handles batch processing correctly")
|
|
|
|
# Test 4: Network Composition
|
|
print("\n4. Network Composition Test:")
|
|
# Create a feature extractor and classifier separately
|
|
feature_extractor = Sequential([
|
|
Dense(input_size=10, output_size=5),
|
|
ReLU(),
|
|
Dense(input_size=5, output_size=3),
|
|
ReLU()
|
|
])
|
|
|
|
classifier_head = Sequential([
|
|
Dense(input_size=3, output_size=2),
|
|
Softmax()
|
|
])
|
|
|
|
# Test composition
|
|
raw_data = Tensor(np.random.randn(5, 10))
|
|
features = feature_extractor(raw_data)
|
|
final_predictions = classifier_head(features)
|
|
|
|
assert features.shape == (5, 3), "Feature extractor should output 3 features"
|
|
assert final_predictions.shape == (5, 2), "Classifier should output 2 classes"
|
|
|
|
row_sums = np.sum(final_predictions.data, axis=1)
|
|
assert np.allclose(row_sums, 1.0), "Composed network predictions should be valid"
|
|
print("✅ Network composition works correctly")
|
|
|
|
print("\n🎉 Comprehensive test passed! Your networks work correctly for:")
|
|
print(" • Multi-class classification (Iris flowers)")
|
|
print(" • Regression tasks (housing prices)")
|
|
print(" • Deep learning architectures")
|
|
print(" • Network composition and feature extraction")
|
|
|
|
except Exception as e:
|
|
print(f"❌ Comprehensive test failed: {e}")
|
|
|
|
print("📈 Final Progress: Complete network architectures ready for real ML applications!")
|
|
|
|
# Run the test
|
|
test_unit_network_architectures()
|
|
|
|
# %% nbgrader={"grade": false, "grade_id": "networks-compatibility", "locked": false, "schema_version": 3, "solution": false, "task": false}
|
|
#| export
|
|
class MLP:
|
|
"""
|
|
Multi-Layer Perceptron (MLP) class.
|
|
|
|
A convenient wrapper around Sequential networks for standard MLP architectures.
|
|
Maintains parameter information and provides a clean interface.
|
|
|
|
Args:
|
|
input_size: Number of input features
|
|
hidden_size: Size of the single hidden layer
|
|
output_size: Number of output features
|
|
activation: Activation function for hidden layer (default: ReLU)
|
|
output_activation: Activation function for output layer (default: Sigmoid)
|
|
"""
|
|
|
|
def __init__(self, input_size: int, hidden_size: int, output_size: int,
|
|
activation=ReLU, output_activation=None):
|
|
self.input_size = input_size
|
|
self.hidden_size = hidden_size
|
|
self.output_size = output_size
|
|
|
|
# Build the network layers
|
|
layers = []
|
|
|
|
# Input to hidden layer
|
|
layers.append(Dense(input_size, hidden_size))
|
|
layers.append(activation())
|
|
|
|
# Hidden to output layer
|
|
layers.append(Dense(hidden_size, output_size))
|
|
if output_activation is not None:
|
|
layers.append(output_activation())
|
|
|
|
self.network = Sequential(layers)
|
|
|
|
def forward(self, x):
|
|
"""Forward pass through the MLP network."""
|
|
return self.network.forward(x)
|
|
|
|
def __call__(self, x):
|
|
"""Make the MLP callable."""
|
|
return self.forward(x)
|
|
|
|
# %% [markdown]
|
|
|
|
def test_unit_sequential_networks():
|
|
"""Unit test for the Sequential network implementation."""
|
|
print("🔬 Unit Test: Sequential Networks...")
|
|
|
|
# Test basic Sequential network
|
|
net = Sequential([
|
|
Dense(input_size=3, output_size=4),
|
|
ReLU(),
|
|
Dense(input_size=4, output_size=2),
|
|
Sigmoid()
|
|
])
|
|
|
|
x = Tensor([[1.0, 2.0, 3.0]])
|
|
y = net(x)
|
|
|
|
assert y.shape == (1, 2), "Sequential network should produce correct output shape"
|
|
assert np.all(y.data > 0), "Sigmoid output should be positive"
|
|
assert np.all(y.data < 1), "Sigmoid output should be less than 1"
|
|
|
|
print("✅ Sequential networks work correctly")
|
|
|
|
# Run the test
|
|
test_unit_sequential_networks()
|
|
|
|
def test_unit_mlp_creation():
|
|
"""Unit test for the MLP creation function."""
|
|
print("🔬 Unit Test: MLP Creation...")
|
|
|
|
# Test different MLP architectures
|
|
shallow = create_mlp(input_size=4, hidden_sizes=[5], output_size=1)
|
|
deep = create_mlp(input_size=4, hidden_sizes=[8, 6, 4], output_size=2)
|
|
|
|
x = Tensor([[1.0, 2.0, 3.0, 4.0]])
|
|
|
|
# Test shallow network
|
|
y_shallow = shallow(x)
|
|
assert y_shallow.shape == (1, 1), "Shallow MLP should work"
|
|
|
|
# Test deep network
|
|
y_deep = deep(x)
|
|
assert y_deep.shape == (1, 2), "Deep MLP should work"
|
|
|
|
print("✅ MLP creation works correctly")
|
|
|
|
# Run the test
|
|
test_unit_mlp_creation()
|
|
|
|
def test_unit_network_architectures():
|
|
"""Unit test for different network architectures."""
|
|
print("🔬 Unit Test: Network Architectures...")
|
|
|
|
# Test different activation functions
|
|
relu_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1, activation=ReLU)
|
|
tanh_net = create_mlp(input_size=3, hidden_sizes=[4], output_size=1, activation=Tanh)
|
|
|
|
# Test multi-class classifier
|
|
classifier = create_mlp(input_size=3, hidden_sizes=[4], output_size=3, output_activation=Softmax)
|
|
|
|
x = Tensor([[1.0, 2.0, 3.0]])
|
|
|
|
# Test all architectures
|
|
y_relu = relu_net(x)
|
|
y_tanh = tanh_net(x)
|
|
y_multi = classifier(x)
|
|
|
|
assert y_relu.shape == (1, 1), "ReLU network should work"
|
|
assert y_tanh.shape == (1, 1), "Tanh network should work"
|
|
assert y_multi.shape == (1, 3), "Multi-class classifier should work"
|
|
assert abs(np.sum(y_multi.data) - 1.0) < 1e-6, "Softmax outputs should sum to 1"
|
|
|
|
print("✅ Network architectures work correctly")
|
|
|
|
# Run the test
|
|
test_unit_network_architectures()
|
|
|
|
def test_unit_network_applications():
|
|
"""Comprehensive unit test for network applications in real ML scenarios."""
|
|
print("🔬 Comprehensive Test: Network Applications...")
|
|
|
|
# Test multi-class classification
|
|
iris_classifier = create_mlp(input_size=4, hidden_sizes=[8, 6], output_size=3, output_activation=Softmax)
|
|
iris_samples = Tensor([[5.1, 3.5, 1.4, 0.2], [7.0, 3.2, 4.7, 1.4], [6.3, 3.3, 6.0, 2.5]])
|
|
iris_predictions = iris_classifier(iris_samples)
|
|
|
|
assert iris_predictions.shape == (3, 3), "Iris classifier should work"
|
|
row_sums = np.sum(iris_predictions.data, axis=1)
|
|
assert np.allclose(row_sums, 1.0), "Predictions should sum to 1"
|
|
|
|
# Run the test
|
|
test_unit_network_applications()
|
|
|
|
# %% [markdown]
|
|
"""
|
|
## 🧪 Module Testing
|
|
|
|
Time to test your implementation! This section uses TinyTorch's standardized testing framework to ensure your implementation works correctly.
|
|
|
|
**This testing section is locked** - it provides consistent feedback across all modules and cannot be modified.
|
|
"""
|
|
|
|
# %% nbgrader={"grade": false, "grade_id": "standardized-testing", "locked": true, "schema_version": 3, "solution": false, "task": false}
|
|
# =============================================================================
|
|
# STANDARDIZED MODULE TESTING - DO NOT MODIFY
|
|
# This cell is locked to ensure consistent testing across all TinyTorch modules
|
|
# =============================================================================
|
|
|
|
# %% [markdown]
|
|
"""
|
|
## 🔬 Integration Test: End-to-End Network Forward Pass
|
|
"""
|
|
|
|
# %%
|
|
def test_module_full_network_forward_pass():
|
|
"""
|
|
Integration test for a complete forward pass through a multi-layer network.
|
|
|
|
Tests a complete forward pass through a multi-layer network,
|
|
integrating Tensors, Dense layers, Activations, and the Sequential container.
|
|
"""
|
|
print("🔬 Running Integration Test: Full Network Forward Pass...")
|
|
|
|
# 1. Define a simple 2-layer MLP
|
|
# Input (3) -> Dense(4) -> ReLU -> Dense(2) -> Output
|
|
model = Sequential([
|
|
Dense(3, 4),
|
|
ReLU(),
|
|
Dense(4, 2)
|
|
])
|
|
|
|
# 2. Create a batch of input Tensors
|
|
# Batch of 5 samples, each with 3 features
|
|
input_tensor = Tensor(np.random.randn(5, 3))
|
|
|
|
# 3. Perform a forward pass through the entire network
|
|
output_tensor = model(input_tensor)
|
|
|
|
# 4. Assert the final output is correct
|
|
assert isinstance(output_tensor, Tensor), "Network output must be a Tensor"
|
|
assert output_tensor.shape == (5, 2), f"Expected output shape (5, 2), but got {output_tensor.shape}"
|
|
print("✅ Integration Test Passed: Full network forward pass is successful.")
|
|
|
|
# %% [markdown]
|
|
"""
|
|
## 🤖 AUTO TESTING
|
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"""
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# %%
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if __name__ == "__main__":
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test_module_full_network_forward_pass()
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from tito.tools.testing import run_module_tests_auto
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# Automatically discover and run all tests in this module
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success = run_module_tests_auto("Networks")
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# %% [markdown]
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"""
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## 🎯 MODULE SUMMARY: Neural Network Architectures
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Congratulations! You've successfully implemented complete neural network architectures:
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### What You've Accomplished
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✅ **Sequential Networks**: Chained layers for complex transformations
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✅ **MLP Creation**: Multi-layer perceptrons with flexible architectures
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✅ **Network Architectures**: Different activation patterns and output types
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✅ **Integration**: Real-world applications like classification and regression
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### Key Concepts You've Learned
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- **Sequential Processing**: How layers chain together for complex functions
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- **MLP Design**: Multi-layer perceptrons as universal function approximators
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- **Architecture Choices**: How depth, width, and activations affect learning
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- **Real Applications**: Classification, regression, and feature extraction
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### Next Steps
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1. **Export your code**: `tito package nbdev --export 04_networks`
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2. **Test your implementation**: `tito test 04_networks`
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3. **Build complete models**: Combine with training for full ML pipelines
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4. **Move to Module 5**: Add convolutional layers for image processing!
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**Ready for CNNs?** Your network foundations are now ready for specialized architectures!
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""" |