Hacker News: SimplyUnknown

New comment by SimplyUnknown in "The Burrows-Wheeler Transform"

SimplyUnknown — Fri, 10 Oct 2025 08:27:11 +0000

I'm still not sure I get it. I think it is

1. Put the BWT string in the right-most empty column

2. Sort the rows of the matrix such that the strings read along the columns of the matrix are in lexicographical order starting from the top-row????

3. Repeat step 1 and 2 until matrix is full

4. Extract the row of the matrix that has the end-delimiter in the final column

It's the "sort matrix" step that seems under-explained to me.

New comment by SimplyUnknown in "I'm Unsatisfied with Easing Functions"

SimplyUnknown — Wed, 23 Jul 2025 21:43:37 +0000

I have the feeling that B-splines would be a good solution for this problem. Given that they have a continuous zeroth (i.e., the function is continuous), first, and second derivative, the motion will always be smooth and there will be no kinks. However, maybe it's moving the problem because now you must tune the coefficients of the B-spline instead of damping parameters (even though a direct mapping between these must exist but this mapping may not be trivial).

New comment by SimplyUnknown in "Why JPEGs Still Rule the Web After 30 Years (2024)"

SimplyUnknown — Tue, 17 Jun 2025 15:48:27 +0000

Multiple reasons, while technically better and more benign compression artifacts, it is computationally more expensive, limited quality improvements, encumbered by patents, poor Metadata format, poor colorspace support... In the end, the benefits aren't great enough compared to jpeg to change the default format

New comment by SimplyUnknown in "I don't like NumPy"

SimplyUnknown — Thu, 15 May 2025 20:55:44 +0000

I really like einops. This works for numpy, pytorch and keras/tensorflow and has easy named transpose, repeat, and eimsum operations.

New comment by SimplyUnknown in "Tumor-derived erythropoietin acts as immunosuppressive switch in cancer immunity"

SimplyUnknown — Fri, 25 Apr 2025 18:48:39 +0000

Full paper link for the interested: https://ehdijrb3629whdb.tiiny.site

New comment by SimplyUnknown in "Pixel is a unit of length and area"

SimplyUnknown — Thu, 24 Apr 2025 06:25:12 +0000

In medical imaging, data are often acquired using anisotropic resolution. So a pixel (or voxel in 3D) can be an averaged signal sample originating from 2mm of tissue in one direction and 0.9mm in another direction.

New comment by SimplyUnknown in "Solving Boolean satisfiability and integer programming with Python packaging"

SimplyUnknown — Tue, 26 Nov 2024 09:52:17 +0000

Conda indeed is slow. However, mamba is a drop in replacement for Conda and uses a way faster solver, which makes it a lot more palatable.

New comment by SimplyUnknown in "Visualizing World War II"

SimplyUnknown — Tue, 12 Nov 2024 17:03:59 +0000

Not quite what you are looking but if you're interested in Operation Market Garden: for the Dutch maps there is https://www.topotijdreis.nl, which gives you historical maps with a year slider. This can at least help one visualize how cities, villages, and topography at through the years.

New comment by SimplyUnknown in "National Popular Vote Interstate Compact"

SimplyUnknown — Mon, 12 Aug 2024 22:01:49 +0000

CGP Grey also made an excellent video about it, which he dubbed the NaPoVoInterCo: https://www.youtube.com/watch?v=tUX-frlNBJY

New comment by SimplyUnknown in "Kolmogorov Complexity and Compression Distance (2023)"

SimplyUnknown — Sat, 30 Mar 2024 22:48:45 +0000

But Chinese (or mandarin) is not a context-free grammar whereas I believe that encoding a language on a turing machine implies a context-free grammar so this example doesn't hold.

New comment by SimplyUnknown in "Is Cosine-Similarity of Embeddings Really About Similarity?"

SimplyUnknown — Tue, 12 Mar 2024 08:15:58 +0000

I think maybe it's poorly phrased. As far as I can tell, their linear regression example for eq. 2 has an unique solution, but I think they state I that when optimizing for cosine similarity you can find non-unique solutions. But I haven't read in detail.

Then again, you could argue whether that is a problem when considering very high dimensional embeddings. Their conclusions seem to point in that direction but I would not agree on that.

New comment by SimplyUnknown in "Synthetic data generation for tabular data"

SimplyUnknown — Wed, 28 Feb 2024 09:45:02 +0000

The thing is you use synthetic data to when it is difficult to obtain real data. For example, in medical imaging, it is very expensive to collect MRI scans to build a large dataset. Not to mention the potential privacy issues and obtaining informed consent to publish the dataset. Synthetic datasets can help here to, for example, pretrain your model and fine tune on real data afterwards. I'm then assuming that collecting tabular data can face similar issues which prevent building large datasets.

New comment by SimplyUnknown in "Advent of Code 2023's new AI/LLM Policy"

SimplyUnknown — Mon, 16 Oct 2023 16:32:22 +0000

Surely not, but if you practicing to get better at programming using AoC, LLMs are unlikely to help you.

New comment by SimplyUnknown in "Advent of Code 2023's new AI/LLM Policy"

SimplyUnknown — Mon, 16 Oct 2023 15:58:06 +0000

Maybe better programmer not so much, but I'd say the spirit of AoC is to crack a puzzle and translate the solution into code. Solving this using LLM will not help you getting better at solving puzzles, solving puzzles, or grasp the main concepts of a programming language. In that sense, ChatGPT is not a pedagogical asset in this particular instance.

New comment by SimplyUnknown in "Mistral 7B"

SimplyUnknown — Wed, 11 Oct 2023 15:52:14 +0000

Obviously you can, but in the grand scheme of things people should share more details about their method so people can improve on it in the future, no?

New comment by SimplyUnknown in "Mistral 7B"

SimplyUnknown — Wed, 11 Oct 2023 15:38:48 +0000

I mean, you can't just share the weights of the model and call it a day, right? You have to share details on what and why you are doing. You must communicate this somehow. In theory, you might be able to do this in a github readme, but a paper-style document on arxiv is nicely suited for this.

New comment by SimplyUnknown in "Northern summer was hottest on record by a significant margin"

SimplyUnknown — Wed, 06 Sep 2023 14:09:30 +0000

I guessed as much, but I wasn't able to confirm. Thanks for the search.

New comment by SimplyUnknown in "Northern summer was hottest on record by a significant margin"

SimplyUnknown — Wed, 06 Sep 2023 13:43:20 +0000

So the solution would be to continue emitting greenhouse gases and ensure it will also get worse in 30 or 50 years?

> The best time to plant a tree was 20 years ago, the second best time is now.

Said to be a Chinese proverb, but I haven't extensively verified.

The only viable solution right now to combat global warming is to immediately stop emitting greenhouse gases, even if there is a lag effect.

New comment by SimplyUnknown in "Do Machine Learning Models Memorize or Generalize?"

SimplyUnknown — Thu, 10 Aug 2023 17:34:54 +0000

First of all, great blog post with great examples. Reminds me of distill.pub used to be.

Second, the article correctly states that typically L2 weight decay is used, leading to a lot of weights with small magnitudes. For models that generalize better, would it then be better to always use L1 weight decay to promote sparsity in combination with longer training?

I wonder whether deep learning models that only use sparse fourier features rather than dense linear layers would work better...

New comment by SimplyUnknown in "Have attention spans been declining?"

SimplyUnknown — Tue, 25 Jul 2023 08:23:35 +0000

Not all of these are mutually exclusive, but there is also a fourth option:

- ADHD was severely underdiagnosed in the past and got more accurately diagnosed in recent years