Ciro's Edict #5 / \Include and \x and working on dynamic website Updated +Created
This was the major final step of fully integrating the OurBigBook CLI into the dynamic website (besides fixing some nasty bugs that escaped passed by me from the previous newsletter).
The implementation was done by "simply" reusing scopes, e.g.: cirosantilli's article about mathematics has scope cirosantilli and full ID cirosantilli/mathematics.
That on the website is equivalent to a local file structure of:
cirodown/mathematics.bigb
The problem is that a bunch of subdirectory scope operations were broken locally as well, as it simply wasn't a major use case. But now they became a major use case for , so I fixed them.
Light year Updated +Created
Politics of Brazil Updated +Created
Ciro's Edict #5 / Next steps Updated +Created
  • upload all of cirosantilli.com to ourbigbook.com. I will do this by implementing an import from filesystem functionality based on the OurBigBook CLI. This will also require implementing slit headeres on the server to work well, I'll need to create one Article for every header on render.
  • get \x and \Include working on the live web preview editor. This will require creating a new simple API, currently the editor jus shows broken references, but final render works because it goes through the database backend
  • implement email verification signup. Finally! Maybe add some notifications too, e.g. on new comments or likes.
Ciro's Edict #5 / Skip ID extraction and rendering based on database timestamps Updated +Created
Now that we can reliably split files at will with \Include, I finally added this feature.
This means while developing a website locally with the OurBigBook CLI, if you have a bunch of files with an error in one of them, your first run will run slowly until the error:
extract_ids README.ciro
extract_ids README.ciro finished in 73.82836899906397 ms
extract_ids art.ciro
extract_ids art.ciro finished in 671.1738419979811 ms
extract_ids ciro-santilli.ciro
extract_ids ciro-santilli.ciro finished in 1009.6256089992821 ms
extract_ids science.ciro
error: science.ciro:13686:1: named argument "parent" given multiple times
extract_ids science.ciro finished in 1649.6193730011582 ms
but further runs will blast through the files that worked, skipping all files that have sucessfully converted:
extract_ids README.ciro
extract_ids README.ciro skipped by timestamp
extract_ids art.ciro
extract_ids art.ciro skipped by timestamp
extract_ids ciro-santilli.ciro
extract_ids ciro-santilli.ciro skipped by timestamp
extract_ids science.ciro
so you can fix file by file and move on quickly.
This was not fully trivial to implement because we had to rework how duplicate IDs are checked. Previously, we just nuked the DB every time on a directory conversion, and then repopulated everything. If a duplicated showed up on a file, it was a duplicate.
But now that we are not necessarily extracing IDs from every file, we can't just nuke the database anymore, otherwise we'd lose the information. Therefore, what we have to do is to convert every file, and only at the end check the duplicates.
Ciro's Edict #6 / Next steps Updated +Created
Make article editing more reasonable. Several bugs in the area.
States of Brazil Updated +Created
History of Brazil Updated +Created
Sequelize example Updated +Created
To run examples on a specific database:
All examples can be tested on all databases with:
cd sequelize
./test
Overview of the examples:
Phenylalanine Updated +Created
How many "la"s does a name need to have?
Ciro Santilli's hardware / Toshiba MK1059GSM Updated +Created
~1TB.
Internal hard drive likely removed from some old computer I lost track of, kept in a crappy case, incredible stuff.
Ubuntu 20.04 gnome-disks benchmark, NTFS partition: 40MB/s.
Eigendecomposition of a matrix Updated +Created
Every invertible matrix can be written as:
where:
Note therefore that this decomposition is unique up to swapping the order of eigenvectors. We could fix a canonical form by sorting eigenvectors from smallest to largest in the case of a real number.
Intuitively, Note that this is just the change of basis formula, and so:
Gavin Andresen Updated +Created
Spontaneous parametric down-conversion Updated +Created
Phenomena that produces photons in pairs as it passes through a certain type of crystal.
You can then detect one of the photons, and when you do you know that the other one is there as well and ready to be used. two photon interference experiment comes to mind, which is the basis of photonic quantum computer, where you need two photons to be produced at the exact same time to produce quantum entanglement.
Video 1.
One Photon In, TWO Photons Out by JQInews (2010)
Source.
Mentions that this phenomena is useful to determine the efficiency of a single photon detector, as you have the second photon of the pair as a control.
Also briefly describes how the input energy and momentum must balance out the output energy and momentum of the two photons coming out (determined by the output frequency and angle).
Shows the crystal close up of the crystal branded "Cleveland Crystals Inc.". Mentions that only one in a billion photon gets scattered.
Then shows their actual optical table setup, with two tunnels of adjustable angle to get photons with different properties.
Video 2.
How do you produce a single photon? by Physics World (2015)
Source.
Very short whiteboard video by Peter Mosley from the University of Bath, but it's worth it for newbs. Basically describes spontaneous parametric down-conversion.
One interesting thing he mentions is that you could get single photons by making your sunglasses thicker and thicker to reduce how many photons pass, but one big downside problem is that then you don't know when the photon is going to come through, that becomes essentially random, and then you can't use this technique if you need two photons at the same time, which is often the case, see also: two photon interference experiment.
Schwinger effect Updated +Created

There are unlisted articles, also show them or only show them.