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Cake day: June 16th, 2023

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  • Hugin@lemmy.worldtomemes@lemmy.worldIt's true.
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    2 days ago

    Yeah. The thing that made me “get” quaternions was thinking about clocks. The hands move around in a 2d plane. You can represent the tips position with just x,y. However the axis that they rotate around is the z axis.

    To do a n dimensional rotation you need a n+1 dimensional axis. So to do a 3D rotation you need a 4D axis. This is bassicly a quat.

    You can use trig to get there in parts but it requires you to be careful to keep your planes distinct. If your planes get parallel you get gimbal lock. This never happens when working with quats.


  • Hugin@lemmy.worldtomemes@lemmy.worldIt's true.
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    2 days ago

    No. It’s more what the previous poster said about encoding rotation. It’s just not a xyz axes. It’s current, charge, flux as axes. The trig is how you collapse the 3d system into a 2d or 1d projection. You lose some information but it’s more useful from a spefic reference.

    Without complex numbers you can’t properly represent the information.



  • Hugin@lemmy.worldtomemes@lemmy.worldIt's true.
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    2 days ago

    Yup. When you have a circuit that is not purely resistive the inductive or capacitive load causes the voltage and current to not be in phase. It looks like ohms law is being violated. However the missing part of the energy is in the imaginary component to be returned latter.






  • (i) Peaches. Any firm yellow variety of the species Prunus persica L., excluding nectarine varieties, which are pitted, peeled, and diced, not less than 30 percent and not more than 50 percent.

    (ii) Pears. Any variety, of the species Pyrus communis L. or Pyrus sinensis L., which are peeled, cored, and diced, not less than 25 percent and not more than 45 percent.

    (iii) Pineapples. Any variety, of the species Ananas comosus L., which are peeled, cored, and cut into sectors or into dice, not less than 6 percent and not more than 16 percent.

    (iv) Grapes. Any seedless variety, of the species Vitis vinifera L., or Vitis labrusca L., not less than 6 percent and not more than 20 percent.

    (v) Cherries. Approximate halves or whole pitted cherries of the species Prunus cerasus L., not less than 2 percent and not more than 6 percent, of the following types:

    (a ) Cherries of any light, sweet variety;

    (b ) Cherries artificially colored red; or

    (c ) Cherries artificially colored red and flavored, natural or artificial.

    Provided, That each 127.5 grams (4 1/2 ounces avoirdupois) of the finished canned fruit cocktail and each fraction thereof greater than 56.7 grams (2 ounces avoirdupois) contain not less than 2 sectors or 3 dice of pineapple and not less than 1 approximate half of the optional cherry ingredient.

    (3) Packing media. (i) The optional packing media referred to in paragraph (a)(1) of this section, as defined in § 145.3 are:

    (a ) Water.

    (b ) Fruit juice(s) and water.

    (c ) Fruit juice(s).

    From https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=145.135











  • It was something around 40 TB X2 . We were doing a terrain analysis of the entire Earth. Every morning for 25 days I would install two fresh drives in the cluster doing the data crunching and migrate the filled drives to our file server rack.

    The drives were about 80% full and our primary server was mirrored to two other 50 drive servers. At the end of the month the two servers were then shipped to customer locations.