Vitor

Karma: 817

Vitor 22 Mar 2016 16:18 UTC
19 points
in reply to: Stefan_Schubert’s comment on: Open Thread March 21 - March 27, 2016
Your problem is called a clustering problem. First of all, you need to answer how you measure your error (information loss, as you call it). Typical error norms used are l1 (sum of individual errors), l2 (sum of squares of errors, penalizes larger errors more) and l-infinity (maximum error).

Once you select a norm, there always exists a partition that minimizes your error, and to find it there are a bunch of heuristic algorithms, e.g. k-means clustering. Luckily, since your data is one-dimensional and you have very few categories, you can just brute force it (for 4 categories you need to correctly place 3 boundaries, and naively trying all possible positions takes only n^3 runtime)

Hope this helps.

Vitor 4 May 2016 13:11 UTC
0 points
in reply to: Furcas’s comment on: My Kind of Moral Responsibility
The real danger, of course, is being utterly convinced Christianity is true when it is not.

The actions described by Lumifer are horrific precisely because they are balanced against a hypothetical benefit, not a certain one. If there is only an epsilon chance of Christianity being true, but the utility loss of eternal torment is infinite, should you take radical steps anyway?

In a nutshell, Lumifer’s position is just hedging against Pascal’s mugging, and IMHO any moral system that doesn’t do so is not appropriate for use out here in the real world.

Vitor 12 Jul 2016 21:34 UTC
6 points
in reply to: HungryHobo’s comment on: Open thread, Jul. 11 - Jul. 17, 2016
This will not have any practical consequences whatsoever, even in the long term. It is already possible to perform reversible computation (Paper by Bennett linked in the article) for which such lower bounds don’t apply. The idea is very simple: just make sure that your individual logic gates are reversible, so you can uncompute everything after reading out the results. This is most easily achieved by writing the gate’s output to a separate wire. For example an OR gate, instead of mapping 2 inputs to 1 output like

(x,y) --> (x OR y),

it would map 3 inputs to 3 outputs like

(x, y, z) --> (x,y, z XOR (x OR y)),

causing the gate to be its own inverse.

Secondly, I understand that the Landauer bound is so extremely small that worrying about it in practice is like worrying about the speed of light while designing an airplane.

Finally, I don’t know how controversial the Landauer bound is among physicists, but I’m skeptical in general of any experimental result that violates established theory. Recall that just a while ago there were some experiments that appeared to show FTL communication, but were ultimately a sensor/timing problem. I can imagine many ways in which measurement errors sneak their way in, given the very small amount of energy being measured here.

Vitor 12 Jul 2016 21:56 UTC
4 points
in reply to: Thomas’s comment on: Open thread, Jul. 11 - Jul. 17, 2016
Did you also test what other software (optaplanner as mentioned by HungryHobo, any SAT solver or similar tool) can do to improve those same schedules?

Did you run your software on some standard benchmark? There exists a thing called the international timetabling competition, with publicly available datasets.

Sorry to be skeptical, but scheduling is an NP-hard problem with many practical applications and tons of research has already been done in this area. I will grant that many small organizations don’t have the know-how to set up an automated tool, so there may still be a niche for you, specially if you target a specific market segment and focus on making it as painless as possible.

Vitor 23 Jan 2020 3:04 UTC
5 points
on: Disasters
What is the “total cost of ownership” of supplies? keeping a stockpile fresh requires ongoing maintenance. In addition to direct cost and space required, you regularly have to devote time and attention to it. It just doesn’t seem practical, specially a large supply of fresh water.

An additional cost is the hassle of moving/selling/giving away your stockpile if you move. If you have deep roots in the place you live, this might not be a large consideration, but I’ve moved at least once every 6 years all my life, some times considerably more often (future projection: even more often). “Unnecessary” stuff like this just adds an extra burden to an already burdensome time.

How would you say the value of having supplies changes as you reduce from 14 days to something smaller? It’s non-linear for sure, so maybe there’s a lower point that’s a good compromise, e.g. 3 days of food and water. Another way of phrasing the question: where does the “two weeks” reference point in your post come from?

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Vitor25 Jan 2020 17:21 UTC

2 points

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Vitor 6 Sep 2020 12:02 UTC
6 points
on: Design thoughts for building a better kind of social space with many webs of trust
I’m intrigued, but this is a bit vague. What kind of thing are you looking to build, concretely? The gestalt I’m getting is this: A social network with a transparent feed / recommendation algorithm that each user can explicitly tune, which as a side effect tags any piece of information with a trust score. This score is implicitly filtered through a particular lens / prior depending on who you trust. Looking at things through different lenses for different purposes is encouraged.
Two thoughts on this:
- It seems to put a lot of administrative burden on users to keep their edges up to date. Can the system be made mostly automatic, e.g. alerting you to changes, suggesting manual review of certain nodes, adjusting weights over time based on your usage, etc? Basically, can you give a user-centric description of the idea, rather than a system-centric one?
- What about strategic incentives? Sure, very blatant voting rings and such can be easily rooted out, but this system would give malicious actors a lot of information to embed themselves in a web in more subtle, insidious manners, e.g. sleeper accounts.

Vitor 12 Nov 2020 11:38 UTC
5 points
on: Being Productive With Chronic Health Conditions
Wholeheartedly agree with this. This covers most of the things I do / aspire to do to manage my own chronic condition.
One area that you don’t really mention is finding work that is flexible and offers social support for the measures you’re implementing for yourself. If your productivity is unreliable, it is a very bad thing to be working a job with lots of hard deadlines, or where your lack of progress will immediately block your co-workers from progressing in their own work. It’s also important to prevent others from assuming you have more slack than you actually do.
In this area, I’ve found pre-committing to be an extremely valuable tool. When I work towards a deadline, I discuss with my boss in advance how bad it would be to miss the deadline, and what our plan B would be in that case (e.g. if 1 week before the deadline things are looking bad, we cut X which we agree is non-essential). This prevents high-stakes, high-pressure discussions from happening while I am in a health crisis, and protects my professional reputation. You don’t want to find out 1 week before the deadline that your boss actually considers X to be essential! Better to find out a month in advance and adjust your plans accordingly.

Vitor 13 Dec 2020 5:03 UTC
1 point
on: Covid 12/10: Vaccine Approval Day in America
> Switzerland is going even slower, making the usual noises about the need for ‘caution.’ My read is that this is because they did not order vaccine doses early enough, and now they are all sold out, so why not spin that by not approving the vaccine for a while and calling it ‘caution?’
This “read” of yours is quite far reaching, going on very little information. It is also completely wrong: Switzerland has contracts with all 3 major vaccine providers, the first of which was signed way back in August, securing 4.5 million doses (covering ~25% of the population).
Source (in german): <https://www.srf.ch/news/schweiz/moderna-impfdosen-gesichert-schweiz-steigt-ins-rennen-um-einen-moeglichen-impfstoff-ein>
So, yes, these delays are indeed because the swiss health authorities are being cautious. The vaccines are going through expedited but otherwise normal approval processes.

Vitor 20 Dec 2020 12:06 UTC
2 points
in reply to: Zvi’s comment on: Covid 12/10: Vaccine Approval Day in America
So, the Swiss just approved the Pfizer vaccine. I think this clearly proves you wrong. However, as I was already planning to write an answer before this new development, let me give you that answer for completeness’ sake (better late than never).
Your original claim sounded a lot stronger than what you’re now saying, where it seems you simply disagree with the exact quantity that is being ordered.
Do you consider it obvious that 5+ doses per person would be optimal? For starters, only about half the population even wants to get vaccinated. Also, the first million doses are clearly worth much more than each additional million. These decisions were made in a very high uncertainty environment, before the effectiveness numbers were known. Switzerland obviously doesn’t have the same market power as other, larger countries, etc. I’m not saying I disagree with your position, just that it is far from obviously correct.
But your original comment went much further than just claiming the swiss ordered the wrong quantity. You implied that Swissmedic (the body in charge of approval) basically has no political independence, and that both the head of Swissmedic and the health minister were brazenly lying to the public when they claimed that they were moving as fast as possible towards approval.
My priors say that these things are pretty unlikely. The delay is much more easily explained by the fact that there is no emergency approval process in Switzerland, which yields a huge status-quo bias for the regular process. To move any faster, new laws would have had to be passed.
So yes, I do think that you made a very far reaching read based on very little information.

Vitor 24 Feb 2021 9:51 UTC
1 point
in reply to: abramdemski’s comment on: Kelly isn’t (just) about logarithmic utility
Comment/question about St. Petersburg and utilities: given any utility function u which goes to infinity, it should be possible to construct a custom St. Petersburg lottery for that utility function, right? I.e. a lottery with infinite expectation but arbitrarily low probability of being in the green. If we want to model an agent as universally rejecting such lotteries, it follows that utility cannot diverge, and thus must asymptotically approach some supremum (also requiring the natural condition that u is strictly monotone). Has this shape of utility function been seriously proposed in economics? Does it have a name?

Vitor 2 Mar 2021 11:52 UTC
2 points
on: Kelly *is* (just) about logarithmic utility
Great post, I find it really valuable to engage in this type of meta-modeling, i.e., deriving when and why models are appropriate.
I think you’re making a mistake in Section 2 though. You argue that a mode optimizer can be pretty terrible (agreed). Then, you argue that any other quantile optimizer can also be pretty terrible (also agreed). However, Kelly doesn’t only optimize the mode, or 2% quantile, or whatever other quantile: it maximizes all those quantiles simultaneously! So, is there any distribution for which Kelly itself fails to optimize between meaningfully different states (as in your 2%-quantile with 10% bad outcome example)? I don’t think such a distribution exists.
(Note: maybe I’m misunderstanding what johnswentworth said here, but if solving for any x%-quantile maximizer always yields Kelly, then Kelly maximizes for all quantiles, correct?)

Vitor 2 Mar 2021 17:18 UTC
1 point
in reply to: abramdemski’s comment on: Kelly *is* (just) about logarithmic utility
That clears up my confusion, thanks!

Vitor 19 Mar 2021 10:31 UTC
1 point
on: Covid 3/18: An Expected Quantity of Blood Clots
Germany has already reversed the AZ stop. Hopefully all other countries will do likewise soon.

Vitor 17 Apr 2021 10:27 UTC
7 points
on: Covid 4/15: Are We Seriously Doing This Again
News from Switzerland: health authorities have made the decision that people who had covid should only get one vaccine shot, 6 months after recovery. This sounds sensible to me, but I’m worried what this means regarding different strains: if someone was infected by the milder variant, aren’t they still at high risk from the newer strains? Anyplace else pursuing similar policies?

Vitor 14 May 2021 10:27 UTC
4 points
on: Covid 5/13: Moving On
Regarding the positivity rate in India stalling out, I would be hesitant to over-interpret this. There is a natural limit to the positivity rate somewhere below 100% (it might even be roughly 25% as we’re currently seeing).
A simple model as an intuition-pump: there are two subgroups. Group 1 would like a test, but will elastically respond to any extra hassle of getting one. Group 2 absolutely needs a test and will not desist, e.g., they strongly believe they have Covid, and without a test they cannot get access to medical treatment. As tests get scarce, group 1 will gradually drop away and test takers converge to being drawn 100% from group 2. But those test-takers will obviously have lower than 100% positivity rate: if this wasn’t the case, we wouldn’t need tests at all! There are other diseases and circumstances that cause people to join group 2.
In a nutshell, positivity rate is only a proxy for undiagnosed Covid cases within some unknown operating envelope (I’m guessing 5-20%?).

Vitor 29 Jul 2021 8:30 UTC
1 point
in reply to: TekhneMakre’s comment on: Black ravens and red herrings
More than the prior, I find the sampling process to be nonsensical. Why would we expect to run across the objects in the world uniformly at random? Seeing ravens is highly correlated with being outside, looking at the sky, etc, so why wouldn’t seeing white ravens have similar but much narrower requirements, like being on a specific island? Adding something along these lines to our model should make the bayesian evidence gained by observing either black ravens or non-black non-ravens quickly go to 0.

Vitor 10 Sep 2021 23:25 UTC
3 points
in reply to: Neel Nanda’s comment on: Covid 9/9: Passing the Peak
Agreed. Also to note: I took a bunch of taxis during 2020 (for doctor’s appointments and such) and I was often their first/only client of the day, so the driver is not necessarily someone with above average exposure to infected people. The circumstances probably change a lot by place / time / lockdown level, so it’s worth taking into account the specifics of your situation.

Vitor 16 Sep 2021 13:43 UTC
36 points
in reply to: brummli’s comment on: I wanted to interview Eliezer Yudkowsky but he’s busy so I simulated him instead
Hard disagree. I like to know what it is I’m reading. I got the strange feeling that this text was way more powerful/cogent than what I thought GPT-3 was capable of, and I feel very mislead that one of the crippling defects of GPT-3 (inability to maintain long-term coherency) was in fact being papered over by human intervention.
Not knowing beforehand sure did help me train my bullshit detector, though.

Vitor 16 Sep 2021 17:32 UTC
19 points
in reply to: theme_arrow’s comment on: I wanted to interview Eliezer Yudkowsky but he’s busy so I simulated him instead
The responses are cherry-picked, so this is way better than what GPT-3 is capable of. See the discussion in the downvoted subthread.

Vitor

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