Adam Optimizer from scratch | Gradient descent made better | Foundations for ML [Lecture 26]

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Why the Adam Optimizer Is a Game-Changer in Machine Learning
If you’ve trained a machine learning model recently, chances are you’ve used Adam. It’s one of the most popular optimization algorithms, and for good reason—it combines the best features of Momentum and RMSprop to deliver fast, stable, and adaptive learning. But what makes Adam so special? Let’s break it down.

The Basics of Adam
Adam (short for Adaptive Moment Estimation) does two key things:

Smooths Gradients with Momentum: It keeps a running average of past gradients to stabilize updates.
This average is calculated by combining a fraction of the previous average (usually 90%) with the current gradient.
Scales Learning Rates Dynamically: Adam tracks the square of past gradients and uses it to scale updates, ensuring parameters with large gradients get smaller steps and those with small gradients get larger ones.
Finally, to ensure early iterations don’t slow down due to initialization, Adam applies bias correction to both averages, ensuring they accurately reflect the gradients.

Why Use Adam?
Faster Convergence: By combining momentum and adaptive learning rates, Adam is quicker and more stable than traditional gradient descent.
Works Out of the Box: Adam performs well across a wide variety of tasks with default settings—90% momentum, 99.9% decay for gradient scaling, and a learning rate of 0.001.
Handles Noisy Gradients: It’s perfect for tasks where gradients vary wildly or data is sparse.
Where Adam Shines
Adam is widely used in:

Deep Learning: From Convolutional Neural Networks (CNNs) to Recurrent Neural Networks (RNNs) and Transformers, Adam is the default optimizer.
Sparse Data: For applications like natural language processing, recommendation systems, and text classification.
Large-Scale Models: Adam’s ability to adapt learning rates per parameter makes it ideal for complex, high-dimensional tasks.
The Takeaway
Adam isn’t just another optimizer—it’s the gold standard for most machine learning tasks. Its combination of momentum and adaptive learning rates ensures stable and efficient optimization, saving time and effort when training models.

What’s your experience with Adam? Do you rely on it, or do you have another favorite optimizer? Let’s discuss in the comments!