robryk @robryk@qoto.org
I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work on weird ML (we'll see how it goes), am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.
I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.
If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.
I appreciate it if my grammar or style is corrected (in any of the languages I use here).
Joined Nov 2020
I'm not sure if that's anyhow fast, but you could perform the comparison (ending with an all-ones byte where it succeeded and all-zeroes elsewhere), AND it with a vector that has (2^i)-i in i-th position, OR it up, add 1, and use any of the scalar ways of figuring out which power of two that is.
(Alternatively, have the second vector have 2^i in i-th position, AND it with first, add them up and use a scalar way to figure out which is the highest bit set.
Your argument (modulo the part about traces being left everywhere) applies off the Internet too, right? (Or are the 3 people purely a metaphor for machines?)
Anyone or everyone?
I'm confused what it would do upon detection: it would have to substitute something in place of the real imagery. What would that thing be and how would it keep it consistent for (a) various rotations (b) various objects placed behind the object being imaged?
I could imagine this being easier to pull of with CT, but Vidisco (based on a single glance on their website) seems to sell imaging devices that have a single emitter and a single 2d sensor.
@mcc you might be amused by the diminutives (kruczek[1], kruczątko -- this word seems to have surprisingly few of them) and to know that biały kruk (white crow) means a rare old book.
[1] which also means fine print or gotcha
The feature might be logically impossible to implement correctly though.
@temptoetiam@octodon.social @_thegeoff
On shallow enough angles you get more reflection (and maybe even more reflection than scattering). This gets exploited by https://en.wikipedia.org/wiki/Wolter_telescope
I actually realised now that I don't understand why the angles need to be shallower for gamma (Fresnel equations imply that reflectivity for a given direction and polarisation of beam depends only on refractive index -- with no reflection at all for equal refractive indices -- and in the around-visible range refractive indices tend to grow with decreasing wavelength).
@eoaiuastwg Does fellow have different connotations or is it not gender-neutral (or both)?
And if you have a directory with a colon in its path (a totally legit character for filenames), you are screwed.
There's something simple that works that escapes me this moment. Just one comment: if you get it via a soundcard-like input you get real values, because you shifted it to baseband and IIUC lost the distinction between negative and positive frequencies. If it was shifted s.t. carrier wasn't DC you'd IIRC be able to retrieve the expected complex signal (because carrier-eps and carrier+eps are distinguishable frequencies).
Yes. And that isn't affected by components of the signal of sufficiently different frequencies (with the "sufficient" distance being on the order of magnitude of 1/sampling window).
Ah, and you need to have these be counterrotating (i.e. flip the sign of time in quadratureXXX definitions).
The reason that works is that if you have a spinny thing that spins significantly more than once during your sampling period, the value of the spinny thing will average to zero. If the spinny thing makes much less than one revolution, the average will be close to something on the unit circle. So, for a signal that's a single sine wave this should work well to detect whether its frequency is close to the given frequency (up until the point when aliasing becomes a problem -- which is when the spinny thing spins at least ~once between two adjacent samples).
It also works for arbitrary signals because everything up to the point where you take the absolute value is linear, and all the uninteresting signals contribute ~0.
No, absolute value of the mean rather than mean of the absolute value.
Don't you mean "pointwise multiply" when you say convolve? (Then, the _resulting signal_ would average out to 0 if the sine was absent and to a complex number with absolute value prop. to sine's strength in the original signal and arg indicating the phase offset. Note that this is about the average of the signal and not the absolute value of the signal.)
Why do you want RMS of a complex signal? What is the physical thing you are trying to model?
ISTM that the transformation that #rust does to bodies of async functions to split them into pieces-between-await-calls requires unsafe blocks (if we hold a ref from one block to another, the ref remains valid only by virtue of !Unpin around its target and so we start relying on things that cannot be expressed in the type/lifetime system for safety).
Is there a macro library/something that would allow me to do something similar _without writing unsafe myself_?
Yes, magnitude(mean) != mean(magnitude).
Mean of complex numbers is useful or not in a very contextual way :) (e.g. see why the Fourier basis is linearly independent).
It seems that numpy is slightly silly and your options for computing squared norm is either np.real(x)**2+np.imag(x)**2 or np.abs(x)**2.
Isn't `x**2` literally the square, which will be a complex value that just rotates twice as quickly?
Do you need a dome, or just a room of any convex shape with high enough ceiling? Parallax shift rates (i.e. angle change per head position linear change) are inversely proportional to distance, so the shifts should be continuous but not necessarily smooth for a non-dome ceiling. I'm not sure what's the threshold for noticeability.
I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work on weird ML (we'll see how it goes), am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.
I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.
If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.
I appreciate it if my grammar or style is corrected (in any of the languages I use here).
Joined Nov 2020
