The orthogonal group is the group of all matrices with orthonormal rows and orthonormal columns Updated 2025-07-16
Or equivalently, the set of rows is orthonormal, and so is the set of columns. TODO proof that it is equivalent to the orthogonal group is the group of all matrices that preserve the dot product.
Tinker Tailor Soldier Spy (TV series) Updated 2025-07-16
- 1: Jim Prideaux captured. Some ex-colleague invites Smiley to dinner and keeps asking how incompetent people like Alleline climbed to the top of the Circus. Smiley recalled to service to meet Ricki Tarr.
- 2: Ricki Tarr tells his story to Smiley. Peter Guillam starts stealing material from the Circus, find missing page on the communication officer list. Smiley sets up his investigation operation.
- 3: Smiley meets Connie who tells that she was fired for suspecting Poliakov. Flashbacks show the ousting of Control and Smiley.
- 4: Guillam steals more material from the circus. While doing that, he is called by the top officers to inquire about Ricki Tarr being in England, which they suspect because they discovered that his family has come.
- 5: Jim Prideaux tells his story to Smiley, who cannot easily access the Circus reports about it. When he is returned to England, there was basically no debriefing, and Esterhase already knew about the Tinker Tailor codenames, presumably through Merlin.
- 6: Smiley hears the story of yet another ousted man, who heard the Russians knew in advance about Jim Prideaux' coming. Toby Esterhase dismissed him for alcoholism.
Vector graphics Updated 2025-07-16
Wikipedia analytics Updated 2025-07-16
Higgs boson Updated 2025-07-16
Mark 17 nuclear bomb Updated 2025-07-16
The Principles of Quantum Mechanics by Paul Dirac (1930) Updated 2025-07-16
Wikipedia CatTree Updated 2025-07-16
This mini-project walks the category hierarchy Wikipedia dumps and dumps them in various simple formats, HTML being the most interesting!
Mathematics dump of Wikipedia CatTree
. Source. Box2D Updated 2025-07-16
Wikipedia dumps Updated 2025-07-16
Per-table dumps created with mysqldump and listed at: dumps.wikimedia.org/. Most notably, for the English Wikipedia: dumps.wikimedia.org/enwiki/latest/
A few of the files are not actual tables but derived data, notably dumps.wikimedia.org/enwiki/latest/enwiki-latest-all-titles-in-ns0.gz from Download titles of all Wikipedia articles
The tables are "documented" under: www.mediawiki.org/wiki/Manual:Database_layout, e.g. the central "page" table: www.mediawiki.org/wiki/Manual:Page_table. But in many cases it is impossible to deduce what fields are from those docs.
Wiley (publisher) Updated 2025-07-16
William Shockley Updated 2025-07-16
Willis Lamb Updated 2025-07-16
Quantum compiler benchmark Updated 2025-07-16
These appear to be benchmarks that don't involve running anything concretely, just compiling and likely then counting gates:
The Spiders' Web: Britain's Second Empire Updated 2025-07-16
2017. Directed by Michael Oswald. Adam Curtis vibes.
Some notable points:
- the role of the British Overseas Territories as tax havens
- the role of the City of London in setting economic policy
- the role of trusts
XPath Updated 2025-07-16
E. Coli K-12 MG1655 gene thrB Updated 2025-07-16
Immediately follows e. Coli K-12 MG1655 gene thrA,
Part of E. Coli K-12 MG1655 operon thrLABC.
House mouse Updated 2025-07-16
SELECT FOR UPDATE Updated 2025-07-16
An example where
SELECT FOR UPDATE is a good solution to an use case can be seen at: nodejs/sequelize/raw/parallel_select_and_update.js.SELECT FOR UPDATE vs/together with the SQL transaction isolation level is commented at: stackoverflow.com/questions/10935850/when-to-use-select-for-update. The horrors of Sequelize Updated 2025-07-16
- foreign keys are capitalized:
- you must give
foreignKeywhen using aliases, otherwise it fails subtely. That would be derived automatically. - stackoverflow.com/questions/41502699/return-flat-object-from-sequelize-with-association can't auto-flatten to reuse the database's
ORDER limitandoffsetdon't work withoutsubQuery: falsewhen doing includes! It is just too buggy. Examples of this can be found e.g. under nodejs/sequelize/many_to_many_same_model.js.- stackoverflow.com/questions/34059081/how-do-i-reference-an-association-when-creating-a-row-in-sequelize-without-assum hard to not duplicate foreign keys values everywhere
- stack traces permanently broken or requiring non-obvious configs:
- does not automatically update fields on hooks: github.com/sequelize/sequelize/issues/8586#issuecomment-422877555
- cannot change columns when other columns have constraints due to the backup table?
- you have to use
.get()forattributealiased fields, why? stackoverflow.com/questions/32649218/how-do-i-select-a-column-using-an-alias/69890944#69890944 .idgets added toSELECTno matter what, breakingGROUP BYunless you do horrible workarounds:- no simple built-in mechanism for transaction retries: Sequelize transaction retries
- impossible to do subqueries in general. Docs just tell you to use literals. This in particular prevents single query deletes with join as done at nodejs/sequelize/raw/many_to_many.js:Also, you can't get query strings either: github.com/sequelize/sequelize/issues/2325
- sequelize.org/master/manual/sub-queries.html: the docs actually just tell you to use literals, lol
- stackoverflow.com/questions/45354001/nodejs-sequelize-delete-with-nested-select-query
- migrations. Generally speaking, anything but the simplest migrations are exceedingly hard to get right, as you have to go very low level when doing migrations. Syntax can be very different from regular DB operations.
- no way to do (non-raw) queries during migrations, e.g. to update fields based on other fields in a complex way?
- github.com/sequelize/cli/issues/862
- stackoverflow.com/questions/18742962/add-data-in-sequelize-migration-script
- stackoverflow.com/questions/38671483/sequelize-migration-update-model-after-updating-column-attributes
- stackoverflow.com/questions/38998397/can-i-use-sequelize-models-in-migration-scripts
- stackoverflow.com/questions/45286429/custom-query-on-sequelize-seeder
queryInterface.sequelize.modelscontains onlySequelizeMeta. Not sure why they have this limitation. - stackoverflow.com/questions/56043246/node-js-sequelize-no-primary-keys-when-migrating/56046101#56046101
- SQLite
changeColumnmigrations do on delete cascades of other tables. SQLite does not have change column statements, so they have to drop and recreate tables, but they don't temporarily remove cascades, so you lose data: stackoverflow.com/questions/62667269/sequelize-js-how-do-we-change-column-type-in-migration/70486686#70486686 - associations require full explicit index construction: stackoverflow.com/questions/39651853/how-to-create-join-table-with-foreign-keys-with-sequelize-or-sequelize-cli
- ability to iterate over a large result without blowing up memory and without using limit + offset (which is inneficient e.g. when looping over recursive queries). This is also known as cursor or streaming interfaces:E.g. the Python SQLite interface supports this just fine: stackoverflow.com/questions/29582736/python3-is-there-a-way-to-iterate-row-by-row-over-a-very-large-sqlite-table-wi
- stack overflow
- stackoverflow.com/questions/28787889/how-can-i-set-up-sequelize-js-to-stream-data-instead-of-a-promise-callback
- stackoverflow.com/questions/43964067/how-to-implement-cursor-pagination-using-sequelize
- stackoverflow.com/questions/57164242/perform-sequelize-findall-in-a-huge-array
- stackoverflow.com/questions/55191891/how-to-loop-through-result-in-sequelize generic loop
- issue tracker
- stack overflow
- empty
attributes: []breaks some nested queries: github.com/sequelize/sequelize/issues/16436 - does not expose a iteration API that supports large arrays?E.g. Python SQLite does: stackoverflow.com/questions/29582736/python3-is-there-a-way-to-iterate-row-by-row-over-a-very-large-sqlite-table-wi
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