Hacker News Reader

pjbkon Elderly Florida couple killed after their Tesla crashes into semi

That is the reason Mansfield bars were introduced, after Jayne Mansfield's accident that killed her and everyone else on the first row seat:

https://www.curbsideclassic.com/uncategorized/vintage-review....

Incredible to think how her children on the back seat survived (including Mariska Hargitay).

pjbkon Vangelis’ film score for Blade Runner

What a wonderful album. Like "Direct", it features many explorations using new digital synths from the late 80s. Fun fact: the voice-overs were done by Polanski and his wife Emmanuelle Seigner (she acts in the "The Ninth Gate" with Johnny Depp). They used to hang out at Vangelis' studio.

pjbkon Vangelis has died

CS80 indeed. There is an almost identical patch for the Arturia CS-80v if interested:

https://www.synthtopia.com/content/2017/10/19/free-arturia-c...

pjbkon Vangelis has died

Ugh. Risky Business, Thief, The Keep, Firestarter, Sorcerer, Legend, Near Dark, Miracle Mile... Perhaps not as major as Chariots of Fire, but nonetheless.

pjbkon ‘It was the poor man’s studio’: how Amiga computers reprogrammed modern music

I was delighted to discover "Bars and Pipes" which was a very well designed software for comping and far superior than using trackers. Even the earlier versions of Cakewalk on the PC were still missing some of the interesting features that made you productive in BnP. To this day some people still fire up BnP and use it to create music!

pjbkon Melting KiCad

My experience exactly.

Kicad 6 feels a bit like a modernized version of Protel 99, with far less bugs too. So it is like Altium going back in time and choosing the correct development path instead of all the nonsense and disrespect for its users of the last two decades.

pjbkon The Kalman filter: helping chickens cross the road

That is why, even in systems where it seems straightforward how to choose the system variables, it is important to do a system identification analysis before committing to any form of Kalman processing. It provides performance and stability assurances, and is what separates the amateurs from the pros.

pjbkon JetBrains Mono – the free and open-source typeface for developers

It's a bit taller than the usual PT Mono I regularly use. I find that "boxier" mono fonts are a bit more readable than elongated ones.

pjbkon What the world will be like in a hundred years (1922)

Interesting to see how sacrificing some freedoms to give more freedom to others in the short term, eventually enhances your same former freedoms in the medium or long term.

pjbkon Gabriel Boric, a Former Student Activist, Is Elected Chile’s Youngest President

I wouldn't generalize. Every country is different and also countries and conditions change in time. Although Chile was also cheering back in 1970 and we all know how that turned out.

pjbkon Gabriel Boric, a Former Student Activist, Is Elected Chile’s Youngest President

Norway is a small, educated, oil-lucky, well managed "socialist" country whose welfare backbone is a fiercely protected sovereign fund that relies on diversified investments in the capitalisms of the world and thus their correct outer and inner-workings.

pjbkon Gabriel Boric, a Former Student Activist, Is Elected Chile’s Youngest President

Having several Cuban and Venezuelan friends and acquaintances (I'm a Chilean living in Florida), it's interesting to become aware of the real dynamics that happen under sanctions in these countries. The sanctions are mostly political in nature but in the case of Cuba it didn't stop imports from operating. I realized this early during flyovers over Cuba and watching the numerous cargo ships and small vessels going in and out of ports and docks. A cousin of one of my colleagues at work in Miami spent his weekends making deliveries of goods that eventually made to the island. He only got in trouble with the Coast Guard when one time he was bringing back some folks that wanted to illegally immigrate to the US using the special laws they have for people fleeing the island. They told him if they ever find out he was doing it again they would confiscate his boat and face prison time. After Obama restrictions have been lifted further.

The sad thing is that only the people related to the party are the ones able to afford most of the stuff traded in the black market, or plainly are the main contacts importing illegal goods. If you are a common citizen your only option is to become something like a bartender in a tourist hotel, which essentially makes you close to products like food, liquor and electronics that have sanction exemptions that you can illegally buy and trade in the black market. BTW, when they explained me this 10 years ago the going entry "price" to become a bartender was over 10k USD, several lifetime salaries of many people in Cuba. Therefore as you can imagine this translates in lots of corruption and the only people that gets affected by sanctions in reality is the common man.

Venezuela is no different. I once met some young Venezuelans whose dad was a military general in the country. All his family was lavishly living and studying in Miami. Somebody else told me that after Chavez there has never been so many high rank officials, all essentially millionaires, that protect that part of Venezuela's ruling class that aligned with the regime. If they used to be rich, like in the Russia after the perestroika now they practically own the country. Just browse in YouTube all the videos of people that visit the Caracas luxury malls, fully stocked supermarkets and fast food restaurants. A common person needs to work a full week to be able to buy a McDonald's meal. To guard critical infrastructure facilities and gas stations they have a special police that in practice has a license to kill.

pjbkon Crohn’s Disease: Is the Cold Chain Hypothesis Still Hot?

My dad was diagnosed with CD around 20 years ago. Besides going through the usual cortisone treatments to control his flares and monoclonal antibodies starting with Remicade, then a couple of other ones that were less effective and now Humira, he has discovered that eating a cup of boiled Durvillaea kelp every day helps with his symptoms: https://en.wikipedia.org/wiki/Durvillaea_antarctica. It seems to have some nutrients similar to mucilagen that acts like a buffer in his case.

pjbkon How imaginary numbers were invented [video]

Huh? Clifford and Cayley-Dickson Algebras?

pjbkon How imaginary numbers were invented [video]

With complex numbers in polar form the tangent is easy. In the unitary circle, if you derive e^(i*t) you get i*e^(i*t), which maps the cos(t) real component to i*cos(t) imaginary, and the i*sin(t) imaginary component to -sin(t) real. This is effectively a 90 degree rotation, so if you integrate the tangent infinitesimally over its path parameterized by t you will recover the circle.

Here is some introductory material to what I referenced above and some generalizations into more dimensions (which, as Hamilton discovered when stumbling into quaternions trying to augment complex numbers, is not as straightforward as you would think):

- Why i? [http://www.stat.physik.uni-potsdam.de/~pikovsky/teaching/stu...]

- An Introduction to Geometric Algebra with an Application in Rigid Body Mechanics [https://www.researchgate.net/profile/Terje-Vold/publication/...]

- Functions of Multivector Variables [https://journals.plos.org/plosone/article/file?id=10.1371/jo...]

- Lie Group Theory - A Completely Naive Introduction [https://jakobschwichtenberg.com/naive-introduction-lie-theor...]

- Previous HN discussion: Intuitive Understanding of Euler’s Formula [https://news.ycombinator.com/item?id=18325865]

pjbkon How imaginary numbers were invented [video]

If you realize where e comes from, which is compounding and what we call an exponential process, being that "the current rate of change is proportional to the present value", then the exponential of a complex number is no different to the exponent of a real number. In the case of one-dimensional real numbers you assign the slope of the function to the current value. The complex case is exactly the same, but if you think instead in the two-dimensional Argand plane and complex algebra, the slope is the tangent to a circle proportional to the angle at that radius (which curve is the one that at every point the slope is equal to its complex value?).

Therefore with the rules of complex arithmetic the tangent provides the "curling" effect in the curvature of a periodic circle, while in the real case you get the common compounding shape of the exponential curve. The relation to sine and cosine is just the projection into direct(real)/quadrature(imaginary) components in either fixed or intrinsic coordinates. Same when you expand the exponential into its complex power series.

BTW, this is actually the essence of infinitesimal transformations in continuous groups and the exponential map, which generalizes this concept to other types of numbers or abstract objects (i.e. Lie group theory).

pjbkon How imaginary numbers were invented [video]

> in addition to real and complex numbers there are higher dimensional numbers namely hypercomplex numbers i.e quaternion and octanion numbers, and no other valid numbering systems beyond that.

To be precise, no other multi-dimensional numbers beyond octonions (which lack associativity) that follow the behavior of complex numbers. There are indeed an infinite amount of multivector numbers with different algebraic rules.

pjbkon How imaginary numbers were invented [video]

That is correct. In the Clifford formulation that is equivalent (and in general a superset) of complex numbers you can choose the dimension or behavior to be whatever you want it to be in the resulting algebra. You can even assign it a particular metric or nullify it. The 'square to -1' that implies quadrature is just a specialization in that case. Many algebraic things of complex numbers like the exponential map still work or have general counterparts.

pjbkon A Note About Recruiters

"You can’t just send random bullshit and expect meaningful results"

Huh, isn't that the way nature works?

My thoughts precisely.

pjbkon Prince of Persia has been released for the Atari XL/XE

I think you should appreciate the fact that the guy opens up bluntly and sincerely in his books, acknowledging he is a human being with opinions, fears and struggles like everyone else. If you are into technology for the purpose of creating art or a software developer in particular, it is refreshing and cultivating to read how other people have faced challenges with the limitations of our instruments or our own minds: when you have the drive to achieve a goal and then truly realize all the effort it takes, the mundane aspects of going into business deals, coping with lack of initiative, burnout, and then pushing yourself back together.

I praise him for keeping diaries while developing Karateka and Prince of Persia, and then publishing them allowing us to take a raw look of how things were for him during that time of his life.

pjbkon Mihály Csíkszentmihályi has died

Oh, what a loss. I think I first heard of his work in Lyall Watson's book Neophilia in the late 80s. I was so mesmerized by the concept of flow that was always looking for anything new Csikszentmihalyi had published, or any psychology or neuroscience studies about flow and related ideas on human cognition. He will certainly be missed.

pjbkon Facebook Recruiter Correspondence

Seriously, I think one of the biggest misconceptions people with opinions like yours might have is that we are somehow unified in these decisions or occurrences – we are not – and the healthy dissent is what, over time, hopefully bends us in the right direction.

Oh, the irony. Well it looks like the "healthy dissent" gets you out the door. Perhaps that is the right direction the recruiter was referring to?

pjbkon Python and Lua (2019)

Through the years starting from around 1998 I deployed Lua into several embedded systems: hardware debugging tools, scientific instruments, medical devices, home automation and finally robotics. Back then you couldn't beat the small footprint of the environment and the decent availability of libraries so you didn't need to start everything from scratch. In contrast, for example the Pawn language was also competent for similar applications but its ecosystem was quite lacking.

Some years ago when Squirrel started to get traction, particularly due to its adoption in a couple of IoT frameworks, I fiddled with it for some months and it almost got its way into a commercial electronics project. However by then uPython was getting more popular, had better tooling support and ARM microcontroller chips had become very fast. Being able to reuse the same code on the host with minimal or no changes, or having an interface or emulation layer that you can also program in Python is a game changer. It took me less than a week to rewrite the Squirrel code to Python, with even better features thanks to the language facilities.

I thought I was never going to touch Lua again but a couple of months ago I found myself hacking some REAPER audio processing scripts, and cursing Ierusalimschy once more for his decision on neglecting Dijkstra's advice and not starting indexes from zero...

pjbkon Found a program I wrote in 1981 and decided to bring it back to life

My astronomical 6502 assembly routines (ca 1987) compile and run fine in embedded simulators. Through the years it has always been in my todo list to port them to C, then Lisp, then C++, then Java, then Python, then Rust... But alas they do exactly what they need to do so the priority to rewrite them falls out of the map. And the main project why they were written in first place, a telescope interferometer controller, still remains unfinished.

pjbkon Live: SpaceX to launch four civilians to orbit in mission known as Inspiration4

This one was a blast to watch from Melbourne (Florida), about 50 miles south from Kennedy Space Center. It lit up half of the evening sky, weather accommodating. Sorry for the shaky video.

https://www.youtube.com/watch?v=GHJuz-D6D9o

pjbkon Supporting half-precision floats is annoying

Depends on what you want to do and how you interpret your data. IIRC we only needed to normalize one parameter in the host using percentages instead in the UI. For the rest everything translated without modification since the F16 covered the max/min parameter ranges.

Mind this was for a regulated medical device and therefore any change in the software was burdensome. The change didn't affect the internal calculations since it was only for the communication protocol and UI, and the compiler support allowed the minimal changes on both embedded and host source codes.

pjbkon Supporting half-precision floats is annoying

Some years ago I used them to transfer real-time waveforms from a medical device via USB and BLE links since they provided more than enough precision for the clinical application. The 2x bandwidth increase without resorting to compression (and its computational overhead) allowed us to meet the project specifications just by changing the type of the data array and recompiling.

pjbkon Europe is now a corporate also-ran. Can it recover its footing?

Nor productivity:

https://www.oecd-ilibrary.org/sites/b2774f97-en/1/2/1/index....

pjbkon Working at a startup is overrated, both financially and emotionally

My humble recommendation: If the company has a valuation or is close to one, ask them to add the necessary money for early exercising to your signing bonus, which is usually pennies on the dollar for them. Then do it the moment you get your options converted to stock.

In that way you minimize any tax risks and at the same time you test how much the company is interested in you and values their employees.

pjbkon I’ve had the same supper for 10 years

That's trial and error knowledge gathered through billions of years and quintillions of individuals from multitude species. Hard to compete with that.