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David Kipping
Exoplanets & Exomoons, Cool Worlds Lab, Columbia University
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David Kipping 4. velj
Odgovor korisniku/ci @Astro_Wright @SB_AlphaCephei
Yes!
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David Kipping 4. velj
Odgovor korisniku/ci @SB_AlphaCephei
I’d say that’s actually too general because it’s two-way. I want the one way transition into a lower energy state only....
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David Kipping 4. velj
Odgovor korisniku/ci @caleb_scharf
Yes along those lines but something formally defined in a bibliographic source ideally!
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David Kipping 4. velj
Odgovor korisniku/ci @Eamonn_Kerins
Perhaps that example is not the best but I think there is a more general definition to be had regarding phase transitions
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David Kipping 4. velj
I’m struggling to find a physics-based formal definition of condensation. Most online describe liquid-gas phase transition. But I want a more general one, for example how the fundamental forces condensed out of a unifying force in the early Universe. Is there something like that?
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David Kipping 3. velj
Most humans will lose consciousness at 5g
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David Kipping proslijedio/la je tweet
James Davenport, PhD 3. velj
Video is now live!! Check it out!
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David Kipping 3. velj
Odgovor korisniku/ci @jradavenport
I was in the live chat!
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David Kipping proslijedio/la je tweet
guy fieri debord 2. velj
I might be the last astronomer to see this but I am in TEARS at the MIRI logo
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David Kipping 3. velj
Odgovor korisniku/ci @alexteachey @fringetracker
Deep cut
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David Kipping 3. velj
Had a blast with Jim, make sure you check out this episode and his wonderful channel!
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David Kipping 3. velj
Odgovor korisniku/ci @TrekCore
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David Kipping 2. velj
I agree but I think you’re describing a summary statistic there rather than the sampler itself. I think the conversation keeps jumping between the two which is making it low SNR. This would just be better to discuss in person next time.
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David Kipping 2. velj
I think it depends on the implementation. For the popular MultiNest code it’s just an issue of turning on the flag nest_pWrap=1. I would think periodic parameters would be easy to deal with irrespective of the sampling algorithm just by using numerical tricks like truncation.
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David Kipping 2. velj
Awesome to be included in this list of educational channels! Especially to be put in the list next to outrageously good !
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David Kipping 2. velj
Yes i usually see something different. I can’t make a plot though - away from my computer. But! If you don’t have any such bias with whatever sampler you’re using then I don’t think there’s any good reason to reparameterize to the Lagrangian-esque components anyway
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David Kipping 2. velj
Odgovor korisniku/ci @exofastupdates @nespinozap i 3 ostali
No we're talking about different effects. LW71 describe how using a summary statistic of a mean/median is positively biased when applied to a posterior near a BC. This is a different effect where the posterior is additionally skewed. Easier just chat next time I see you about it!
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David Kipping 2. velj
Odgovor korisniku/ci @exofastupdates @nespinozap i 3 ostali
This would go away with an infinitesimal proposal size, and maybe could be solved with a better sampler, I think the reparameterization in the OP indeed solves it too. But you don’t really have this issue to fix with nested sampling which I appreciated when I switched!
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David Kipping 2. velj
Odgovor korisniku/ci @exofastupdates @nespinozap i 3 ostali
The problem I found nested sampling avoids is that if my mcmc makes a proposal from e=0.01 with a Gaussian proposal of 0.02, there’s a decent chance it will try a negative e that is forbidden. So it’s biased toward accepting positive jumps here, which skews the posterior.
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David Kipping 2. velj
Odgovor korisniku/ci @CuriousTerran @JasonFRowe i 2 ostali
I actually don’t use that reparameterization since I stopped using Markov chains. Nested sampling doesn’t suffer from artificially positively biased posteriors against boundary conditions as troubles MCMC.
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