TuxGuitar Updated 2025-07-16
Just use MuseScore instead.
Can import from: MIDI.
Ubuntu 20.04:
sudo apt install tuxguitar tuxguitar-alsa tuxguitar-jsa tuxguitar-osstuxguitar-jsa was needed, otherwise no sound: askubuntu.com/questions/457321/tuxguitar-no-sound-in-14-04Has OK step sequencer non-realtime up/down/left/right guitar based composition interface.
Has chord insertion.
Has bend editor.
Could be more amazing, but it is OK.
A bit limited by being very "guitar oriented". Shows you guitar strings, and you enter offset to each string. So to enter two adjacent notes you need to use two seprate strings and thing about the offsets. If only it had a more piano based interface.
Drum notation is also atrocious, you have to go to the top chord, and use high numbers starting at 36.
Two photon interference experiment Updated 2025-07-16
Can be achieved in two ways it seems:
- macroscopic beam splitter and optical table
- photolithography
Animation of Hong-Ou-Mandel Effect on a silicon like structure by Quantum Light University of Sheffield (2014): www.youtube.com/watch?v=ld2r2IMt4vg No maths, but gives the result clear: the photons are always on the same side.
- quantum dot source. TODO how do you produce identical photons from two separate quantum dots? See also: quantum dot single photon source.
- superconducting nanowire detector. So the device has to be cooled then? Video "Jeremy O'Brien: "Quantum Technologies" by GoogleTechTalks (2014)" youtube.com/watch?v=7wCBkAQYBZA&t=2497 however says that semiconducting devices can also be used
Ubuntu 21.10 does not wake up from suspend Updated 2025-07-16
Please refer to Video "Linus Torvalds saying "Nvidia Fuck You" (2012)".
Does not happen every time, only some times. Can't figure out why. Usually happens when has suspended for a longer time.
bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-470/+bug/1946303 sounds like a likely report, Nvidia driver version 470, but can't find those error messages anywhere. The last line of:once was:which is when sleep starts.
journalctl -o short-precise -k -b -1PM: suspend entry (deep)This suggests that it is not a video bug then, seems that it is not waking up at all? Gotta try to SSH into it. OK. I did SSH into it, and that was fine, so it is just the video that won't start.
PM: suspend exitbugs.launchpad.net/ubuntu/+source/linux/+bug/1949977 is another possible bug, based on kernel version. I'm running 5.13, which is one of the failing versions on the report. Can't find any interesting dmesg though.
In another crash:had the following interesting lines:and there was a corresponding
journalctl -o short-precise -k -b -1nvidia-modeset: WARNING: GPU:0: Lost display notification (0:0x00000000); continuing.
[24307.640014] NVRM: GPU at PCI:0000:01:00: GPU-18af74bb-7c72-ff70-e447-87d48378ea20
[24307.640018] NVRM: Xid (PCI:0000:01:00): 79, pid=8828, GPU has fallen off the bus.
[24307.640021] NVRM: GPU 0000:01:00.0: GPU has fallen off the bus.
[24328.054022] nvidia-modeset: ERROR: GPU:0: The requested configuration of display devices (LGD (DP-4)) is not supported on this GPU.
[repeats several more times]
[24328.056767] nvidia-modeset: ERROR: GPU:0: The requested configuration of display devices (LGD (DP-4)) is not supported on this GPU.
[24328.056951] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:0:0:0x0000000f
[24328.056955] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:1:0:0x0000000f
[24328.056959] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:2:0:0x0000000f
[24328.056962] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:3:0:0x0000000f
[24328.056983] nvidia-modeset: ERROR: GPU:0: DP-4: Failed to disable DisplayPort audio stream-0
[24328.056992] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000947d:0:0:0x0000000f/var/crash/_usr_sbin_gdm3.0.crash.Related "GPU has fallen off the bus": askubuntu.com/questions/868321/gpu-has-fallen-off-the-bus-nvidia
Ubuntu 23.04 boot broken on kernel 6.2 Updated 2025-07-16
The solution on kernel 6.2 was:as per comments under: bugs.launchpad.net/ubuntu/+source/linux/+bug/2012559. This also made the nvidia driver work: Find GPU information in Ubuntu.
sudo apt instal nvidia-driver-515Previously I had:and it blew up before reaching disk decryption.
nvidia-driver-510I also tried:but that broke in a different way:
nvidia-driver-525Finished apport-autoreport.service - Process error reports when automatic reporting is enabled.
nvidia-modeset: ERROR: GPU:0: Idling display engine timed out: 0x0000947d:0:0:407
(1 of 2) Job systemd-backlight@backlight: nvidia_e.service/start running (32s no limit) Unable to lock screen on Ubuntu Updated 2025-07-16
However it did not happen on Lenovo ThinkPad P51 (2017) also on Ubuntu 23.10 which had been upgraded several times from God knows what starting point... At first one had X11 (forced by Nvidia drivers) and the other Wayland, but moving to p14s X11 changed nothing.
Both were running GNOME Display Manager.
Same happens with Super + L, but also CLI commands: askubuntu.com/questions/7776/how-do-i-lock-the-desktop-screen-via-command-line
Bibliography:
- askubuntu.com/questions/1242110/after-upgrading-to-ubuntu-20-04-lockscreen-not-working canon
- askubuntu.com/questions/1246622/ubuntu-20-04-unable-to-lock-screen
- askubuntu.com/questions/1245071/cant-lock-screen-with-shortcut-on-ubuntu-20-04-gnome
- askubuntu.com/questions/1248756/super-l-not-working-on-ubuntu-20-04
Undecidable problem Updated 2025-07-16
Or in other words: there is no Turing machine that always halts for every input with the yes/no output.
Every undecidable problem must obviously have an infinite number of "possibilities of stuff you can try": if there is only a finite number, then you can brute-force it.
Lists of undecidable problems.
Coolest ones besides the obvious boring halting problem:
Upsert with
NOT NULL column Updated 2025-07-16Attempt at nodejs/sequelize/raw/upsert.js:
- stackoverflow.com/questions/48816629/on-conflict-do-nothing-in-postgres-with-a-not-null-constraint OP unable to provide a minimal exampe, but it is likely the problem
- dba.stackexchange.com/questions/292428/postgresql-upsert-issue-with-not-null-columns
Variety Jones Updated 2025-07-16
2023 Silk Road's Second-in-Command Gets 20 Years in Prison www.wired.com/story/silk-road-variety-jones-sentencing/
2016 "Exclusive: Our Thai prison interview with the alleged top advisor to Silk Road" arstechnica.com/tech-policy/2016/09/exclusive-our-thai-prison-interview-with-an-alleged-top-advisor-to-silk-road/
2015 The Variety Show On the trail of the man believed to be Variety Jones, one of the architects of the defunct drug marketplace Silk Road. www.vice.com/en/article/wnx5qn/the-variety-show
www.justice.gov/usao-sdny/file/797251/download some kind of case file of his trial.
Bibliography:
The curious thing about VJ is that he actually has some culture and says cool things, e.g.:
Verilator interactive example Updated 2025-07-16
The example under verilog/interactive showcases how to create a simple interactive visual Verilog example using Verilator and SDL.
You could e.g. expand such an example to create a simple (or complex) video game for example if you were insane enough. But please don't waste your time doing that, Ciro Santilli begs you.
The example is also described at: stackoverflow.com/questions/38108243/is-it-possible-to-do-interactive-user-input-and-output-simulation-in-vhdl-or-ver/38174654#38174654
Usage: install dependencies:then run as either:Tested on Verilator 4.038, Ubuntu 22.04.
sudo apt install libsdl2-dev verilatormake run RUN=and2
make run RUN=moveFile overview:
Video game console Updated 2025-07-16
Who needs a hackable general purpose computer, when you can buy a completely locked down computer that only runs useless programs for which you have to pay thousands of dollars to develop for, cannot run a large percentage of major titles from competitor hardware due to business deals (see also) and will inevitably reach planned obsolescence in 4 years?
Webdev's Creed Updated 2025-07-16
Without me, my stack is useless. Without my stack, I am useless. I must fire my requests true. I must shoot straighter than my hackers who are trying to kill me. I must shoot him before he shoots me. I will ...My stack is human, even as I am human, because it is my life. Thus, I will learn it as a brother. I will learn its weaknesses, its strength, its parts, its accessories, its ORMs and its asset bundlers. I will keep my stack clean and ready, even as I am clean and ready. We will become part of each other. We will ...
Explanation: this is an allusion to the Rifleman's Creed. This particular version talks about the website stack chosen for a website, i.e. the libraries used.
Ciro Santilli has always felt that choosing a stack is an almost religious choice. It is perhaps part of why the prayer style of the original Rifleman's Creed resonates with the web stack choice.
It is very hard to know how things are going go, the ups and downs, before putting big hours into it.
And once you start, it is hard, though not impossible, to move away.
webpack Updated 2025-07-16
Webpack is like a magic hydra that can eat any type of file and bundle it into a single output: .js, .ts, .ccs, .scss, .jsx, .tsx,
require, import, import css from .js, it doesn't matter at all, it just digests all into the same dump.When it works, you are just left in awe and with a single Js file. When it doesn't, you're fucked and have to debug for several hours.
Demos under: webpack/. To run all of them by default:To easily make changes and reload the .js output live let this run on a terminal:
cd webpack/min
npm install
npm run build
xdg-open index.htmlnpx webpack watchExamples:
- webpack/min: minimal hello world. Doesn't do much, just copies
index.jstodist/index.js. - webpack/require:
requireandimportdemo. Both work from the same file.dist/index.jsnow contains all of:notindex.jsnotindex2.js- Lodash, a common third-party helper library specified in the package.json and installed with npm
- webpack/node: produce Node.js output, as opposed to the default web output. To test it run:Achieved simply with:
npm run build node dist/index.jsas documented at: webpack.js.org/concepts/targets/target: 'node'Fatman in Robin, - webpack/sequelize: attempts at getting Sequelize to work with webpack. It's just not supported by Sequelize:
Website Updated 2025-07-16
What does it mean that photons are force carriers for electromagnetism? Updated 2025-07-16
TODO find/create decent answer.
I think the best answer is something along:
- local symmetries of the Lagrangian imply conserved currents. gives conserved charges.
- OK now. We want a local symmetry. And we also want:Given all of that, the most obvious and direct thing we reach a guess at the quantum electrodynamics Lagrangian is Video "Deriving the qED Lagrangian by Dietterich Labs (2018)"
- Dirac equation: quantum relativistic Newton's laws that specify what forces do to the fields
- electromagnetism: specifies what causes forces based on currents. But not what it does to masses.
A basic non-precise intuition is that a good model of reality is that electrons do not "interact with one another directly via the electromagnetic field".
A better model happens to be the quantum field theory view that the electromagnetic field interacts with the photon field but not directly with itself, and then the photon field interacts with parts of the electromagnetic field further away.
The more precise statement is that the photon field is a gauge field of the electromagnetic force under local U(1) symmetry, which is described by a Lie group. TODO understand.
This idea was first applied in general relativity, where Einstein understood that the "force of gravity" can be understood just in terms of symmetry and curvature of space. This was later applied o quantum electrodynamics and the entire Standard Model.
From Video "Lorenzo Sadun on the "Yang-Mills and Mass Gap" Millennium problem":
- www.youtube.com/watch?v=pCQ9GIqpGBI&t=1663s mentions this idea first came about from Hermann Weyl.
- youtu.be/pCQ9GIqpGBI?t=2827 mentions that in that case the curvature is given by the electromagnetic tensor.
Bibliography:
- www.youtube.com/watch?v=qtf6U3FfDNQ Symmetry and Quantum Electrodynamics (The Standard Model Part 1) by ZAP Physics (2021)
- www.youtube.com/watch?v=OQF7kkWjVWM The Symmetry and Simplicity of the Laws of Nature and the Higgs Boson by Juan Maldacena (2012). Meh, also too basic.
When the École Polytechnique mathematics department didn't let Ciro Santilli do his internship of choice due to grades Updated 2025-07-16
This was one of the only bad experience Ciro had at Polytechnique, besides the inevitable fear of not graduating.
Ciro wanted to do a robotics internship in Germany, linked to his interests in artificial general intelligence, see also: Section "Ciro's 2D reinforcement learning games".
But the head of the applied mathematics department Polytechnique prevented him from going because Ciro didn't have the necessary grades, even though the Germans had already agreed to it: he had a C, but he needed a B. As mentioned at École Polytechnique, most Brazilians had crappy grades due to their Polytechnique-incompatible background.
This was done because in the past students with bad grades had abandoned their internships halfway and given foreigners a bad impression of Polytechnique.
It is impossible to say if the head of department really agreed with this bullshit policy, or if it was something beyond his powers and he hid his true opinion, but it felt like the agreed.
What an extremely limited view!!!
To leave the worse, the worse. To assume that grades mean anything!
And thus Ciro had to choose a last moment internship that he hated, rather than becoming the greatest roboticist that ever lived, and did terribly at it.
At least on the other hand Ciro learnt Python instead of working at the internship, and became the greatest programming tutorial writer that ever lived. Maybe.
Whole cell simulation Updated 2025-07-16
Ciro Santilli started taking some notes at: github.com/cirosantilli/awesome-whole-cell-simulation. but they are going to be all migrated here.
It is interesting to note how one talks about single cell analysis, in contrast to whole cell simulation: experimentally it is hard to analyse a single cell. But theoretically, it is hard to simulate a single cell. This mismatch is perhaps the ultimate frontier of molecular biology.
Why are complex numbers used in the Schrodinger equation? Updated 2025-07-16
This useless video doesn't really explain anything, he just says "it's needed because the equation has an in it".
The real explanation is: they are not needed, they just allow us to write the equation in a shorter form, which is always a win: physics.stackexchange.com/questions/32422/qm-without-complex-numbers/557600#557600
Why can't you collimate incoherent light as well as a laser? Updated 2025-07-16
You could put an LED in a cavity with a thin long hole but then, most rays, which are not aligned with the hole, will just bounce inside forever producing heat.
So you would have a very hot device, and very little efficiency on the light output. This heat might also behave like a black-body radiation source, so you would not have a single frequency.
The beauty of lasers is the laser cavity (two parallel mirrors around the medium) selects parallel motion preferentially, see e.g.: youtu.be/_JOchLyNO_w?t=832 from Video "How Lasers Work by Scientized (2017)"
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