SQL 2D histogram Updated +Created
Let's try it on SQLite 3.40.1, Ubuntu 23.04. Data setup:
sqlite3 tmp.sqlite 'create table t(x integer, y integer)'
sqlite3 tmp.sqlite <<EOF
insert into t values
  (0, 0),
  (1, 1),
  (2, 2),
  (3, 3),
  (4, 4),
  (5, 5),
  (6, 6),
  (7, 7),
  (8, 8),
  (9, 9),
  (10, 10),
  (11, 11),
  (12, 12),
  (13, 13),
  (14, 14),
  (15, 15),
  (16, 16),
  (17, 17),
  (18, 18),
  (19, 19),

  (2, 18)
EOF
sqlite3 tmp.sqlite 'create index txy on t(x, y)'
For a bin size of 5 ignoring empty ranges we can:
sqlite3 tmp.sqlite <<EOF
select
  floor(x/5)*5 as x,
  floor(y/5)*5 as y,
  count(*) as cnt
from t
group by 1, 2
order by 1, 2
EOF
which produces the desired:
0|0|5
0|15|1
5|5|5
10|10|5
15|15|5
And to consider empty ranges we can use SQL genenerate_series + as per stackoverflow.com/questions/72367652/populating-empty-bins-in-a-histogram-generated-using-sql:
sqlite3 tmp.sqlite <<EOF
select x, y, sum(cnt) from (
  select
      floor(x/5)*5 as x,
      floor(y/5)*5 as y,
      count(*) as cnt
    from t
    group by 1, 2
  union
  select *, 0 as cnt from generate_series(0, 15, 5) inner join (select * from generate_series(0, 15, 5))
)
group by x, y
EOF
which outputs the desired:
0|0|5
0|5|0
0|10|0
0|15|1
5|0|0
5|5|5
5|10|0
5|15|0
10|0|0
10|5|0
10|10|5
10|15|0
15|0|0
15|5|0
15|10|0
15|15|5
Let students learn by teaching Updated +Created
Tell students to:
  • make suggestions to the course material themselves, since you have used text and published your source.Review their suggestions, and accept the best ones.
  • answer the questions of other students on your online forum. Let them work instead of you.
Praise those that do this very highly, and give them better grades if you have that superpower.
This is part of a larger concept Ciro Santilli holds dear: don't just consume, but also produce.
Whatever you do, even if it is playing video games: if you manage to produce related content that will interest other people, and possibly allow you to get paid, it will much much fun to do that thing.
Self-adjoint operator Updated +Created
DokuWiki Updated +Created
Matrix operation Updated +Created
Ciro Santilli's knee Updated +Created
If Achilles' had his heel, Ciro had his knee.
First during University in Brazil while trying a kick up during the development of Cirodance his knee went a bit weird for a few weeks.
Then, just after arriving in France for École Polytechnique, the boys were playing indoor soccer, and to impress the girls Ciro was playing really hard, even took off his shirt, and suddenly when he was running by himself his knee snapped, he fell and it hurt like hell.
Ciro was on crutches for a few weeks, but the inflammation went away, but then he tried to play more soccer, but the knee was not as stable as before, and once he tried to run full speed, it slipped and hurt him a bit more (less severely) and so he gave up. For some reason it was not visible on the tomography made at the hospital.
Maybe Ciro should have investigated more though, certainly an experienced doctor could have done a hand pressure exam to determine which joint was damaged manually even. That was a medical failure.
So from this day on Ciro gave up on all interesting sports, and confined himself to more repetitive stuff like gym weights and cycling: Section "Ciro Santilli's sport practice". At Polytechnique he was forced to take up swimming as his mandatory sport, that was unbearably boring.
This defect is likely genetic since a close relative had similar problems.
But oh well, his then not-even girlfriend was impressed enough by the soccer or sorry enough for the sucker to marry him, so it worked out.
Gallium Updated +Created
Germanium Updated +Created
Selenium Updated +Created
Silver Updated +Created
Ytterbium Updated +Created
Not "Yt" because that is already "Yttrium". God.
NFT Marketplace Updated +Created
Metric induced by a norm Updated +Created
In a vector space, a metric may be induced from a norm by using subtraction:
PageRank Updated +Created
When Ciro finally understood that this is a play on Larry Page's name (of course it is, typical programmer/academic humor stuff), his mind blew.
Google project Updated +Created
Proton Updated +Created
Satan Updated +Created
Ubuntu 23.04 boot broken on kernel 6.2 Updated +Created
Switching to the other installed kernel, 5.9 made boot work.
The solution on kernel 6.2 was:
sudo apt instal nvidia-driver-515
as per comments under: bugs.launchpad.net/ubuntu/+source/linux/+bug/2012559. This also made the nvidia driver work: Find GPU information in Ubuntu.
Previously I had:
nvidia-driver-510
and it blew up before reaching disk decryption.
I also tried:
nvidia-driver-525
but that broke in a different way:
Finished 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)
Ciro Santilli's undergrad studies at the University of São Paulo Updated +Created
Ciro's official diploma from the University of São Paulo read "Automation and Control Engineer at the Polytechnic School of the University of São Paulo".
The University of São Paulo had been elected the best South American university in the Times Ranking 2013 (archive) in all subjects.
Ciro finished the course with honors of "The Best Student in Automation and Control of the year 2013".
Ciro didn´t learn basically any control engineering however unfortunately. He did only the 3 base years of the electrical engineering course, and the rest got lost on stupid politics of having to go back to do 6 months from France to validate his Brazilian degree, see also: Section "Don't force international exchange students to come back early".

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