I always found this funny as well. We say ginger cats (chats roux) in French too!

But doesn't roux/rouge just mean "red"?

"Ginger" doesn't mean "red", except for hair color. And that's the interesting part.

Roux is just for hair colour in French. Not the same as rouge.

Ah, thanks, my bad not looking it up, I was feeling so sure I'd know that!

Would you mind sharing some of the insights you gained on reading code? It could be useful for the more junior of us!

Not GP, but the main thing is that there is always some conceptual model being a good codebase. Meaning there’s the problem, then a given set of data structures and algorithms that forms a solution for that model.

It’s often hidden behind the syntax and implementation because of the layers of abstraction. A single operation (semantic wise) may be scattered over many statements, and some definition may be important in several subconcepts. It helps to be familiar with various technical concepts as possible. basic data structures like lists and trees, more advanced concepts like scheduling and concurrency, as well as platform concepts like files, process, networking,…

Why? Because they are implementation details that distract from the main conceptual model. It’s like how OpenBSD handle device discovery and configuration. Once you know that it’s a tree, you just need to remember how you build a tree and then most of the code are obvious. You can then discern the traversal stuff from the actual device configuration easily and know how to focus your reading.

Neat! I wonder how they deal with people using possibly different map projections?

The data collection is standardised through my border drawing game so no issue with that

I think the question comes from (or is at least related to) the recent UN vote on moving from Mercator to Equal Earth projection.

What people are drawing isn't the "truth" on average. First, nobody has seen the world from actual far away (space) and is just using what they remember from school or other media. And second, there is no "truth" because we are fundamentally dealing with a 2d projection of the 3d surface of a sphere and there are many different projections, all with advantages and disadvantages, neither being more correct than any other.

I was wondering the same thing, but playing it you only fill in small border segments at a time, with the rest of the map filled in, so the projection doesn't change much.

The red lines are the only segments filled in via small border segments; the green and the blue lines require you to do much more of the country's outline.

Worst case can mean two things. For fixed n, worst list content and worst k, which gives you the less fine-grained O(n). For fixed n and fixed k, worst list content, which gives you the fine-grained O(n - k).

Edit: Another example of that is the complexity of convolutional filtering, which is O(n min(log n, k)) for a signal of length n and a kernel of size k.

I'm interested in the context surrounding his statement but I could not find where it originates from. Do you have a link to it?

It's a somewhat active inverse problems research subfield https://github.com/MenghanXia/ReversibleHalftoning

That one does not seem to be an undither project, it appears to be a special way to encode chroma information within a monochrome dithered image. NTSC television also encodes chroma within a grayscale signal, but that's different than black and white only.

I'm only vaguely familiar with dithering/half-toning. What does "component" refer to here?

8 bit per component = 0-255 red, 0-255 green, 0-255 blue

Like ~99% of images you encounter on the Web.

red/green/blue

Do you have tips to start using notebooks instead of marking books? I personally like to underline stuff in my books, when I start a new novel it's often people, places and events. I'm not sure what would be the notebook equivalent of that. Writing down what I would underline? It seems tedious and you loose context and the sense of proximity between words.

For my textbooks, I use little record cards. I write the book reference on the top line, then whatever notes or quotations etc. If it's a heavily referred to book, I sometimes use different colour cards to mean different things.

When I return the book to the library etc., I take all my record cards out and put them in a little perspex index box.

Sometimes I use the record cards to then start some more detailed notes in a notebook; sometimes the record cards refer to a page in my notebooks where I've attempted a derivation etc.

I was once telling a friend about a book I had just finished. They were curious about it and asked me to borrow it. I politely accepted knowing very well they could never read my copy for it was embarrassingly covered in the messy marks I had enjoyed making during my read. Fortunately neither of us ever brought the subject again and I now think twice before messing up my books!

I wouldn't consider those things embarrassing. You may even consider it an opportunity to discuss the book at a later date?

> Also, from the fundamental theorem of algebra, once the Jacobian polynomial {\mathrm{det} DF} is non-zero, it must be constant.

I wouldn't have guessed this is true. I'm wondering what the proof looks like!

I’m fairly confident that the blog post is trying to say something like this:

Given a polynomial function from C^n to C^n, the following statements are equivalent: (a) det DF is nonzero everywhere. (b) det DF = c for some constant c != 0

The backward direction (b implies a) is trivial. The forward direction can be proven by observing that det DF is itself a polynomial function from C^n to C. If n were 1, then this would follow directly from the fundamental theorem of algebra: a non constant polynomial has degree at least 1 and hence has at least one zero. Extending this logic to higher dimension is not especially difficult.

I do find the way it’s stated in the article to be confusing.

Ah right this makes a lot of a sense - thanks!