If you have any questions, please ask. I love yapping.

yapLet's say we have some periodic function f. The goal is to represent it as a bunch of sine waves. This is called a Fourier series (FS).

The FS coefficients are given by

            ⌠2⋅π
         1  ⎮         -i⋅k⋅x
f̂(k) =  ─── ⎮   f(x)⋅e       dx
        2⋅π ⌡0

for whole numbers k. We can then approximate the original function with

  n
 ___
 ╲          -i⋅k⋅x
 ╱    f̂(k)⋅e
 ‾‾‾
k = -n             

and make the approximation better by making n larger.

For non-periodic functions, we can still get an approximation! The Fourier Transform (FT) uses a continuous range of frequencies instead of whole numbers, and the sum is replaced by an integral (the inverse FT).

FT's are used everywhere, for example in signal processing and spectroscopy. If a recording contains an annoying high-pitched noise, we can apply the FT and filter the unwanted frequencies. Spectroscopy separates light into its different wavelengths. By comparing the resulting spectral lines with known measurements, we can determine which elements and molecules are present in stars and planets, for example.

idk what more to add ._.


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[–] 15 points 4 days ago (4 children)

After a long and good conversation with a friend she told me monkey-typewriter I should spend less time thinking about negative things?

Chat is this real? Is this a thing you can just do?

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  • [–] 7 points 4 days ago* (1 child)

    It is actually a thing you can change. You don't have to ruminate on negative things all the time. When my last partner broke up with me, I kept looking at photos of us, reading past texts, reliving memories; tearing at the wound to prevent it from healing. I eventually reached a point where I had felt everything there was to feel about it but I still kept hurting myself over it until one night I read through the entire text chain from day one until the end and told myself that was it, that's the end of this cycle. I need to stop doing this to myself because it's a choice that I'm making and I don't have to make this choice.

    Feeling poorly about yourself/your living situation/the future is a little different but the basic facts are still applicable. There are things you can change now and there are things that you can change in the future. Do what you can now and plan for the future. You cannot change the past and ruminating on it is only going to dig you deeper into a pit. You've made big changes in your life and you're not just going to stay where you are right now forever. Things will get better if you let them and if you work towards that. When shit is rough it's so easy to forget how much progress you've made but when you're doing okay you need to make a practice of reinforcing that feeling of progress. Every little victory adds up to the whole of you. You can do this shit, you have been doing this shit, and you'll keep working towards a life that is better for you, if you let yourself.

    I was incredibly self-destructive for much of my life. I had to start over so many times until I confronted those tendencies and stopped giving in to them. I had to allow myself to be okay with making progress, with feeling that I was deserving of a little stability. In my case, I needed a ton of people to call me out on my bullshit before I truly started making changes in how I viewed and treated myself. I hope all of us here are helping to move you to a healthier relationship with yourself trans-heart

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  • [–] 5 points 4 days ago

    This reminds me of a story: when my first girlfriend broke up with me I was devastated. My favorite past time the next year was to get drinky, use music and internet threads to make me sad instead of numb, and then pour through our entire relationship's instant messenger chat logs to see if I could understand where it all went wrong. Finally, I realized how unhealthy it all was and I put every log, every picture, and some other things on a jump drive and gave it to my best friend to keep safe for me until I could be trusted with it again. A couple years after that, I asked them to throw it away, I had finally dug myself out of that hole I dug and moved on. They had lost it XD

    I don't know when I ever would've gotten better had I not put my self-harm material out of reach. It didn't stop every thought, and didn't stop a particularly toxic pattern I had with my ex where she would call whenever her life was falling apart because I always put my own emotional health on hold to be there for her, but it did keep me from my worse self-inflicted rumination pattern.

    (This section isn't toward you SuperZutsuki, but to anyone reading) I don't know how we do that with climate change, negative self talk, the Palestinian genocide, rising fascism, or any of the other nightmares we live with, but if there is a way to put it away, put it into someone you trust's hands until you need it again, try. See if you can take a week of social media, with a friend who will let you know if anything really important happens, if the week goes well maybe make it a month. Find hopeful media to engage with, not bullshit saccharine media, but media where positive seeds are planted and cared for. And maybe most importantly, even though its incredible, awfully frustrating at times, connect with people off line in the work to make the world just a bit better. There are countless ways to do this, labor unions, mutual aid groups, food not bombs orgs, urban farms, communist and/or anarchist groups, etc. You have to be not alone more times than at work if you're ever going to be okay, and you can't be behind a mask then (I mean identity mask, not COVID mask, so you have to be out as your true gender, your real neurotype, etc.) or it won't work. But, baby steps of getting back into the world...see what your public library has available, you might be surprised what kinda things you can do for free.

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  • [–] 7 points 4 days ago

    I struggle with that too, it's specially awful when it just start spiraling into more and more negative thoughts. I found that either trying to maintain myself busy or imagining those thoughts physically going away from me help.

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  • [–] 7 points 4 days ago* (1 child)

    if i didn't learn that skill, i would be a much less happy person. it's not a betrayal to the working class to spend some time not thinking about the unimaginable horrors of the current system. after a certain point, it's sorta lt-dbyf-dubois mode to be so focused on The Gloaming that it's overshadowing the very real issues in one's personal life

    climate change was my issue. i live in a region affected by the changes, taking action to prepare is important, but i can't spend each day monitoring noaa and ipcc and local weather reports

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  • [–] 5 points 4 days ago (1 child)

    Climate change is a brutal doom. Probably the worst thing you can doom about tbh. I mean, the realistic end of the world, how could you not. The more you know the worse it is.

    Tragically there are so many negative things for me to focus on, big picture and personal life :catgirl-flop: maybe I'll get better at the skill. It'd be nice.

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  • [–] 6 points 4 days ago (1 child)

    exactly, the more you learn, the worse you feel, and it has exactly 0 impact on the course of events so i just sorta wallowed in the helplessness. brutal doom indeed.

    focusing on negative things in your personal life can be good and helpful; analysis can help find solutions. but after a certain point or with things outside of our immediate control, i felt an interminable cycle of depressy. you got this Eggnog, one step at a time!

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