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#off-topic
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2020-09-12
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seancorfield00:09:27

@sogaiu Thanks. I'll poke the admin team and see who has the rights to restart it. #community-development is generally the best place to report community-related stuff like that.

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coby03:09:40

Anyone happen to run Netgear Armor? I recently got a Netgeat mesh wifi system and I'm very happy with the speed, but they've also been pushing a subscription to Armor/Bitdefender pretty hard. I'm skeptical bc it seems pretty gimmicky, but also open to informed perspectives.

emccue18:09:23

@idiomancy You want a function where f(x) = k(df/dx)

emccue18:09:35

which e^kx fits

emccue18:09:54

(d/dx) e^kx = ke^kx

emccue18:09:02

but that will grow, not approach 0

emccue18:09:48

(d/dx) e^-kx = -k(e^-kx)

emccue18:09:55

For oscillations in springs particularly the math that describes that can either be given in terms of e^... or with sin and cos

idiomancy18:09:36

ah thats interesting, so its common to use e^... to represent spring forces?

emccue18:09:15

(source: have an undergrad in physics)

emccue18:09:30

well, for the simple harmonic motion case, generally people use sin and cos

emccue18:09:50

there is just a relation between the trig functions and e and people tend to express it in whatever form is more convenient

emccue18:09:22

give me a moment to look up the expressions

idiomancy18:09:49

oh hell yes!

idiomancy18:09:52

thanks for the resource!

emccue18:09:53

I don't think that will be all that much help in actually doing a simulation, but its a start

emccue18:09:22

I also have a notebook from physics in high school that covers that stuff

emccue18:09:59

what you want specifically sounds like spring motion w/ friction

emccue18:09:59

or "dampened oscillation"

emccue18:09:28

The exact shape you are looking for sounds like underdamping

emccue18:09:55

which you more or less get by shoving

emccue19:09:27

where w is 2pi * the frequency you derive

emccue19:09:32

and t is the time

emccue19:09:17

which decays to 0 over time

emccue19:09:29

and a some constants to make it balance out

emccue19:09:03

so an offset in the sin part and a scale multiplication for the whole thing

idiomancy18:09:44

hey @U3JH98J4R just wanted to come back and say thanks! that underdamped oscillator reference was perfect for what I needed and I got it working!

chucklehead19:09:39

I think you might be deriving percentage overshoot from control theory

emccue19:09:00

but this is kinda the "result" of the math - depending on how you make your simulation this might just fall out of doing the forces at each timestep. But in simple cases you can hardcode the math and show it at different time steps

jjttjj19:09:27

i remember seeing a few months ago someone's project on hacker news relating to saving all browsing history, and phone activity, etc, in a searchable format. Does this sound familiar to anyone? Ironically I believe I saved the link somehow, but can't find it via searching my github starts, or pocket, etc :man-facepalming: