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Ji-Ha
5,138 posts
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Ji-Ha
@Ji_Ha_Kim
jiha-kim.github.io
Joined January 2024
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  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Apr 3, 2025
    The more I learn the more I realize everything in ML is copied from physics
    136K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Feb 22, 2025
    I wrote a blog post for an introduction to stochastic calculus! I share my perspective and intuition behind Brownian motion, the connections between random walks, Binomial and normal distributions, or Itô and Stratonovich calculus. It includes some visualizations too!
    GIF
    109K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Mar 8, 2025
    Wow, Qwen web search led me to some Chinese websites, and there is real gold mine of information on machine learning
    76K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Oct 6, 2025
    I discovered this very cool application called Obsidian, it's very good for writing math, especially if you install some plugins that can auto-replace text
    00:00
    416K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Mar 7, 2025
    I stumbled upon a highly underrated paper It studies the dimensionality self-attention geometry via algebraic methods, focusing on a simplified version without softmax but also a short section with it at the end, they have some conjectures if anyone will can prove it
    47K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Mar 28, 2025
    Blog post: The Mean-ing of Loss Functions Inspired by @FrnkNlsn, @ArtemKRSV
    85K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Feb 23, 2025
    I love @bremen79’s explanations on optimization theory, I am inspired to learn more about it. I highly recommend watching his content, lectures and blog posts.
    34K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Jul 12, 2024
    ML is only hard because people obfuscate, overcomplicate and overengineer everything
    user avatar
    Teortaxes▶️ (DeepSeek 推特🐋铁粉 2023 – ∞)
    @teortaxesTex
    Jul 11, 2024
    Prompt engineering is a real profession because in 2024, prompt engineering can look like this
    29K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    May 12, 2025
    I got recommended Terence Tao's YouTube channel created in 2010, where he uploaded his first video just yesterday! He showcases his process of formalizing a proof in Lean 4 with the help of GitHub Copilot and the "canonical" tactic in Lean.
    64K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Dec 3, 2024
    I suspect LLMs are secretly running on complex numbers and we are not exploiting this enough
    user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Dec 1, 2024
    Replying to @Ji_Ha_Kim
    An additional note: complex numbers can be used to represent rotations very simply. Intuitively, RoPE is coupling every 2 consecutive dimensions of the embedding space. Let q = [x1,y1,x2,y2,…] then we update with e^ik(x+iy)=(x cos k - y sin k) + i(x sin k + y cos k), k=ptheta
    77K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Oct 11, 2025
    Very cool fact: the FFT is based on sampling the roots of unity smartly, typically on C. But it actually works for any field! For example, multiplication of very big integers often uses something called "number-theoretic transform", basically FFT on the finite field Z/pZ
    user avatar
    Tom Yeh
    @ProfTomYeh
    Oct 10, 2025
    At MIT, the only course I ever dropped was signal processing. The DFT math was too intimidating. It’s so easy to just type fft() in MATLAB and move on. Years later, I finally did DFT by hand. ✍️ If you are also afraid of DFT, I hope this helps! ⬇️ Download:
    00:00
    47K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Apr 23, 2025
    It’s interesting that transformer dot product self-attention has d_k^2 redundant degrees of freedom. Since setting Q’=QA, K’=K(A^-1)^T gives Q’K’^T=QAA^-1 K^T = QK^T So for d_k = 64 there are 64^2=4096 redundant dimensions since there are dim(GL(n))=n^2 invertible n x n matrices
    56K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Nov 25, 2024
    The inventor of muTransfer, muP, LoRA and GFlowNets also worked on o1’s inference time reasoning. He’s totally unstoppable. It seems like he recently left OpenAI to co-found a stealth AI company in Woodside, California. Definitely something to follow closely
    user avatar
    Edward Hu
    @edwardjhu
    Sep 13, 2024
    proud to see what i worked on at OpenAI finally shipped! go 🐢!!
    46K
  • user avatar
    Ji-Ha
    @Ji_Ha_Kim
    Oct 16, 2025
    The theory of operators is very interesting. Another cool trick: eigen-decomposition of the transpose T, since T^2-I=0, λ=±1. Then projectors P₊=(I+T)/2, P₋=(I-T)/2 decompose into symmetric/antisymmetric parts with A=(A+A^T)/2 + (A-A^T)/2
    user avatar
    CM
    @Creative_Math_
    Oct 15, 2025
    An addendum to @3blue1brown’s video, here is the linear algebra proof behind *why* Laplace transform works. For the ML folks who follow me, you can think of Laplace as a PCA on your ODE, where the “principal components” are the values of s at which your transform has a pole
    32K