nichg

nichg, 1 month ago

@franco_vazza Important to succeeding in persuading them, or important to determining if I will be persuaded?

nichg, 4 months ago

@elizabethtasker Could you dig to the surface, snap some modular parts up there to establish a level, and extend your base down into the caverns via snapped pieces?

nichg, 7 months ago

@albertcardona The norms of academic writing include a lot of formalism and boilerplate that I think tends to make people worse writers when they internalize it - passive voice, burying the ledge, etc. The better world would be one where people could get papers through peer review without making them worse to read. But in the world we have, I can see people wanting to write with looser style and hit a button that turns that into the style that is expected by the scientific community.

nichg, 7 months ago

@albertcardona Sure, but given people can't easily just change the realities of funders and tenure panels looking at impact factor and specific prestige journals, I'm not surprised that people are finding solutions to make it more bearable for them personally, and I can't really justify being categorically against them doing so.

I mean, in my case I personally just left academia entirely because of this stuff which is arguably less constructive than a bad technological bypass.

nichg, 7 months ago

@noneuclideandreamer Check what's happening to your divergence as you iterate Poisson, if you simulate adding grad(P) to your velocity field. That should be decreasing; if its increasing or staying constant, you might have a sign error or coefficient with the wrong value or something.

nichg, 7 months ago

@noneuclideandreamer Torus should be fine as long as you don't care about absolute values of the pressure. If you're on a torus and have no internal boundaries, you can use a Fourier method to solve Poisson exactly in one step.

nichg, 7 months ago

@noneuclideandreamer You can do it component-wise, then project out the part of the Fourier-space velocity field parallel to k (both real and imaginary parts), transform back, and keep only the real part. I think the imaginary part should still be zero when you transform back anyhow, but of course there will be machine precision level errors... You can also just work with pressure, which is a scalar, but then you get errors of order dx.

nichg, 7 months ago

@noneuclideandreamer Well, Poisson's equation where the 'charge' is the divergence of your velocity field. You can derive it by setting: div(v-grad(P))=0. In Fourier space that's just -k^2 P(k) = Fdiv(v)

nichg, 10 months ago

@elizabethtasker So it turns out I'll be travelling to Tokyo this week... and maybe regretting it?

nichg, 11 months ago

@ct_bergstrom @emilymbender I'm careful about arguments from incredulity like this. Even if I can't describe an algorithm for me to do this, I couldn't have described one for distinguishing cats from dogs using a list of pixels either. And there's stuff about few-shot and zero-shot translation using statistical regularities common between languages (https://arxiv.org/abs/1710.11041 and other papers by Artexte). Enough for me to not hurry to a conclusion even if it doesn't fully answer the challenge.