Uploaded June 2024 | Updated September 2026, 1 week ago
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![Neural Networks Demystified [Part 2: Forward Propagation]](https://i.ytimg.com/vi/UJwK6jAStmg/mqdefault.jpg "Neural Networks Demystified [Part 2: Forward Propagation]
Neural Networks Demystified
@stephencwelch
Supporting Code:
https://github.com/stephencwelch/Neural-Networks-Demystified
In this short series, we will build and train a complete Artificial Neural Network in python. New videos every other friday.
Part 1: Data + Architecture
Part 2: Forward Propagation
Part 3: Gradient Descent
Part 4: Backpropagation
Part 5: Numerical Gradient Checking
Part 6: Training
Part 7: Overfitting, Testing, and Regularization")
![Learning to See [Part 8: More Assumptions...Fewer Problems?]](https://i.ytimg.com/vi/UVwwYZMFocg/mqdefault.jpg "Learning to See [Part 8: More Assumptions...Fewer Problems?]
In this series, well explore the complex landscape of machine learning and artificial intelligence through one example from the field of computer vision: using a decision tree to count the number of fingers in an image. Its gonna be crazy.
Supporting Code: https://github.com/stephencwelch/LearningToSee
welchlabs.com
@welchlabs")
![The moment we stopped understanding AI [AlexNet]](https://i.ytimg.com/vi/UZDiGooFs54/mqdefault.jpg "The moment we stopped understanding AI [AlexNet]
Thanks to KiwiCo for sponsoring todays video! Go to https://www.kiwico.com/welchlabs and use code WELCHLABS for 50% off your first month of monthly lines and/or for 20% off your first Panda Crate.
Activation Atlas Posters!
https://www.welchlabs.com/resources/5gtnaauv6nb9lrhoz9cp604padxp5o
https://www.welchlabs.com/resources/activation-atlas-poster-mixed5b-13x19
https://www.welchlabs.com/resources/large-activation-atlas-poster-mixed4c-24x36
https://www.welchlabs.com/resources/activation-atlas-poster-mixed4c-13x19
Special thanks to the Patrons:
Juan Benet, Ross Hanson, Yan Babitski, AJ Englehardt, Alvin Khaled, Eduardo Barraza, Hitoshi Yamauchi, Jaewon Jung, Mrgoodlight, Shinichi Hayashi, Sid Sarasvati, Dominic Beaumont, Shannon Prater, Ubiquity Ventures, Matias Forti
Welch Labs
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Watch on TikTok: https://www.tiktok.com/@welchlabs
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References
AlexNet Paper
https://proceedings.neurips.cc/paper_files/paper/2012/file/c399862d3b9d6b76c8436e924a68c45b-Paper.pdf
Original Activation Atlas Article- explore here - Great interactive Atlas! https://distill.pub/2019/activation-atlas/
Carter, et al., Activation Atlas, Distill, 2019.
Feature Visualization Article: https://distill.pub/2017/feature-visualization/
`Olah, et al., Feature Visualization, Distill, 2017.`
Great LLM Explainability work: https://transformer-circuits.pub/2024/scaling-monosemanticity/index.html
Templeton, et al., Scaling Monosemanticity: Extracting Interpretable Features from Claude 3 Sonnet, Transformer Circuits Thread, 2024.
“Deep Visualization Toolbox by Jason Yosinski video inspired many visuals:
https://www.youtube.com/watch?v=AgkfIQ4IGaM
Great LLM/GPT Intro paper
https://arxiv.org/pdf/2304.10557
3B1Bs GPT Videos are excellent, as always:
https://www.youtube.com/watch?v=eMlx5fFNoYc
https://www.youtube.com/watch?v=wjZofJX0v4M
Andrej Kerpathys walkthrough is amazing:
https://www.youtube.com/watch?v=kCc8FmEb1nY
Goodfellow’s Deep Learning Book
https://www.deeplearningbook.org/
OpenAI’s 10,000 V100 GPU cluster (1+ exaflop) https://news.microsoft.com/source/features/innovation/openai-azure-supercomputer/
GPT-3 size, etc: Language Models are Few-Shot Learners, Brown et al, 2020.
Unique token count for ChatGPT: https://cookbook.openai.com/examples/how_to_count_tokens_with_tiktoken
GPT-4 training size etc, speculative:
https://patmcguinness.substack.com/p/gpt-4-details-revealed
https://www.semianalysis.com/p/gpt-4-architecture-infrastructure
Historical Neural Network Videos
https://www.youtube.com/watch?v=FwFduRA_L6Q
https://www.youtube.com/watch?v=cNxadbrN_aI
Errata
1:40 should be: word fragment is appended to the end of the original input. Thanks for Chris A for finding this one.
CFAQJOTYQHT7JYIT")
![The F=ma of Artificial Intelligence [Backpropagation, How Models Learn Part 2]](https://i.ytimg.com/vi/VkHfRKewkWw/mqdefault.jpg "The F=ma of Artificial Intelligence [Backpropagation, How Models Learn Part 2]
Take your personal data back with Incogni! Use code WELCHLABS and get 60% off an annual plan: http://incogni.com/welchlabs
New Patreon Rewards 29:48 - own a piece of Welch Labs history! https://www.patreon.com/welchlabs
Books & Posters
https://www.welchlabs.com/resources
Sections
0:00 - Intro
2:08 - No more spam calls w/ Incogni
3:45 - Toy Model
5:20 - y=mx+b
6:17 - Softmax
7:48 - Cross Entropy Loss
9:08 - Computing Gradients
12:31 - Backpropagation
18:23 - Gradient Descent
20:17 - Watching our Model Learn
23:53 - Scaling Up
25:45 - The Map of Language
28:13 - The time I quit YouTube
29:48 - New Patreon Rewards!
Nice Implementation for a viewer in C++:
https://kirit.com/Tiny%20Classifiers/tiny-classifier.cpp
Special Thanks to Patrons https://www.patreon.com/welchlabs
Juan Benet, Ross Hanson, Yan Babitski, AJ Englehardt, Alvin Khaled, Eduardo Barraza, Hitoshi Yamauchi, Jaewon Jung, Mrgoodlight, Shinichi Hayashi, Sid Sarasvati, Dominic Beaumont, Shannon Prater, Ubiquity Ventures, Matias Forti, Brian Henry, Tim Palade, Petar Vecutin, Nicolas baumann, Jason Singh, Robert Riley, vornska, Barry Silverman, Jake Ehrlich, Mitch Jacobs, Lauren Steely
References
Werbos, P. J. (1994). The roots of backpropagation : from ordered derivatives to neural networks and political forecasting. United Kingdom: Wiley. Newton quote is on p4, Werbos expands on the analogy on p4.
Olazaran, Mikel. A sociological study of the official history of the perceptrons controversy. *Social Studies of Science* 26.3 (1996): 611-659. Minsky quote is on p 393.
Widrow, Bernard. Generalization and information storage in networks of adaline neurons.” Self-organizing systems (1962): 435-461.
Historical Videos
http://youtube.com/watch?v=FwFduRA_L6Q
https://www.youtube.com/watch?v=ntIczNQKfjQ
Code:
https://github.com/stephencwelch/manim_videos
Technical Notes
Large Llama training animation shows 8/16 layers. Specifically layers 1, 2, 7, 8, 9, 10, 15, and 16. Every third attention pattern is shown, and special tokens are ignored. MLP neurons are downsampled using max pooling. Only the weights and gradients above a specific percentile based threshold are shown. Only query weights are shown going into each attention layer.
The coordinates of Paris are subtracted from all training examples in the 4 city example as a simple normalization - this helps with convergence.
In some scenes, math is happening at higher precision behind the scenes, and results are rounded, which may create apparent inconsistencies.
Written by: Stephen Welch
Produced by: Stephen Welch, Sam Baskin, and Pranav Gundu
Special thanks to: Emily Zhang
Premium Beat IDs
EEDYZ3FP44YX8OWT
MWROXNAY0SPXCMBS
CFAQJOTYQHT7JYIT")
![How To Science [Part 4: Science]](https://i.ytimg.com/vi/Y7kCJtWFpUU/mqdefault.jpg "How To Science [Part 4: Science]
PDF: http://www.welchlabs.com/guides
Support Welch Labs: www.patreon.com/welchlabs
Music:
https://www.premiumbeat.com/royalty-free-tracks/jazz-manouche-forever
https://www.premiumbeat.com/royalty-free-tracks/out-of-the-woods
https://www.premiumbeat.com/royalty-free-tracks/truth-to-tell")
![Imaginary Numbers Are Real [Part 7: Complex Multiplication]](https://i.ytimg.com/vi/YHvR8siIiD0/mqdefault.jpg "Imaginary Numbers Are Real [Part 7: Complex Multiplication]
More information and resources: http://www.welchlabs.com
Imaginary numbers are not some wild invention, they are the deep and natural result of extending our number system. Imaginary numbers are all about the discovery of numbers existing not in one dimension along the number line, but in full two dimensional space. Accepting this not only gives us more rich and complete mathematics, but also unlocks a ridiculous amount of very real, very tangible problems in science and engineering.
Part 1: Introduction
Part 2: A Little History
Part 3: Cardans Problem
Part 4: Bombellis Solution
Part 5: Numbers are Two Dimensional
Part 6: The Complex Plane
Part 7: Complex Multiplication
Part 8: Math Wizardry
Part 9: Closure
Part 10: Complex Functions
Part 11: Wandering in Four Dimensions
Part 12: Riemanns Solution
Part 13: Riemann Surfaces
Want to learn more or teach this series? Check out the Imaginary Numbers are Real Workbook: http://www.welchlabs.com/resources.
Want to learn more or teach this series? Check out the Imaginary Numbers are Real Workbook: http://www.welchlabs.com/resources.")
![Waffles And Harmonic Motion [Part II]](https://i.ytimg.com/vi/ZzVpT8w8ILU/mqdefault.jpg "Waffles And Harmonic Motion [Part II]
In this two part series, we dig into understanding and quantifying simple harmonic motion (SHM). We try to figure our why systems that oscillate move the way they do, and what ideas from physics govern this motion.
I have unapologetically stolen much of my approach from Richard Feynmans wonderful physics lectures: http://www.feynmanlectures.caltech.edu/I_toc.html. The approach presented here was largely borrowed from Feynman chapters 9 and 21. I encourage anyone interesting in going to deeper to read Feynmans lectures.
Supporting code: https://github.com/stephencwelch/Acoustics-To-Deep-Learning/blob/master/Waffles%20And%20Harmonic%20Motion%20%5BPart%20II%5D.ipynb
For more, see www.welchlabs.com/blog")
![How to Science [Part 3: Experiments]](https://i.ytimg.com/vi/b-CPQdWU-sI/mqdefault.jpg "How to Science [Part 3: Experiments]
PDF: http://www.welchlabs.com/guides/
Support Welch Labs: https://www.patreon.com/welchlabs
Music:
https://premiumbeat.com/royalty_free_music/songs/jazz-manouche-forever
https://premiumbeat.com/royalty_free_music/songs/razer-trap")
