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Posts

How do you decide between upvoting and strong upvoting? 2019-08-25T18:19:11.107Z
The case for taking AI seriously as a threat to humanity 2018-12-23T01:00:08.314Z
Pandemic Risk: How Large are the Expected Losses? Fan, Jamison, & Summers (2018) 2018-11-21T15:58:31.856Z

Comment by anonymous_ea on Is it still hard to get a job in EA? Insights from CEA’s recruitment data · 2022-07-20T23:02:37.177Z · EA · GW

Sorry, I'm not sure I understand what your point is. Are you saying that my point 1 is misleading because having even any relevant experience can be a big boost for an applicant's chances to getting hired by CEA, and any relevant experience isn't a high bar?

Comment by anonymous_ea on Is it still hard to get a job in EA? Insights from CEA’s recruitment data · 2022-07-19T20:43:21.446Z · EA · GW

It sounds like there are two, separate things going on:

1. Jobs at CEA are very hard to get, even for candidates with impressive resumes overall.
2. CEA finds it hard to get applicants that have particular desirable qualities like previous experience in the same role.
Comment by anonymous_ea on On Deference and Yudkowsky's AI Risk Estimates · 2022-07-08T22:47:49.254Z · EA · GW

(Of course, this is bound to be a judgment call; e.g. Eliezer didn’t state how many 9’s of confidence he has. It’s not like there’s a universal convention for how many 9’s are enough 9’s to state something as a fact without hedging, or how many 9’s are enough 9’s to mock the people who disagree with you.)

Yes, agreed.

Let me lay out my thinking in more detail. I mean this to explain my views in more detail, not as an attempt to persuade.

Paul's account of Aaronson's view says that Eliezer shouldn't be as confident in MWI as he is, which in words sounds exactly like my point, and similar to Aaronson's stack exchange answer. But it still leaves open the question of how overconfident he was, and what, if anything, should be taken away from this. It's possible that there's a version of my point which is true but is also uninteresting or trivial (who cares if Yudkowsky was 10% too confident about MWI 15 years ago?).

And it's worth reiterating that a lot of people give Eliezer credit for his writing on QM, including for being forceful in his views. I have no desire to argue against this. I had hoped to sidestep discussing this entirely since I consider it to be a separate point, but perhaps this was unfair and led to miscommunication. If someone wants to write a detailed comment/post explaining why Yudkowsky deserves a lot of credit for his QM writing, including credit for how forceful he was at times, I would be happy to read it and would likely upvote/strong upvote it depending on quality.

However, here my intention was to focus on the overconfidence aspect.

I'll explain what I see as the epistemic mistakes Eliezer likely made to end up in an overconfident state. Why do I think Eliezer was overconfident on MWI?

(Some of the following may be wrong.)

• He didn't understand non-MWI-extremist views, which should have rationally limited his confidence
• I don't have sources for this, but I think something like this is true.
• This was an avoidable mistake
• Worth noting that Eliezer has updated towards the competence of elites in science since some of his early writing according to Rob's comment elsewhere this thread
• It's possible that his technical understanding was uneven. This should also have limited his confidence.
• Aaronson praised him for "actually get most of the technical stuff right", which of course implies that not everything technical was correct.
• He also suggested a specific, technical flaw in Yudkowsky's understanding.
• One big problem with having extreme conclusions based on uneven technical understanding is that you don't know what you don't know. And in fact Aaronson suggests a mistake Yudkowsky seems unaware of as a reason why Yudkowsky's central argument is overstated/why Yudkowsky is overconfident about MWI.
• However, it's unclear how true/important a point this really is
• At least 4 points limit confidence in P(MWI) to some degree:
• Lack of experimental evidence
• The possibility of QM getting overturned
• The possibility of a new and better interpretation in the future
• Unknown unknowns
• I believe most or all of these are valid, commonly brought up points that together limit how confident anyone can be in P(MWI). Reasonable people may disagree with their weighting of course.
• I am skeptical that Eliezer correctly accounted for these factors

Note that these are all points about the epistemic position Eliezer was in, not about the correctness of MWI. The first two are particular to him, and the last one applies to everyone.

Now, Rob points out that maybe the heliocentrism example is lacking context in some way (I find it a very compelling example of a super overconfident mistake if it's not). Personally I think there are at least a couple[1] [2] of places in the sequences where Yudkowsky clearly says something that I think indicates ridiculous overconfidence tied to epistemic mistakes, but to be honest I'm not excited to argue about whether some of his language 15 years ago was or wasn't overzealous.

The reason I brought this up despite it being a pretty minor point is because I think it's part of a general pattern of Eliezer being overconfident in his views and overstating them. I am curious how much people actually disagree with this.

Of course, whether Eliezer has a tendency to be overconfident and overstate his views is only one small data point among very many others in evaluating p(doom), the value of listening to Eliezer's views, etc.

1. ^

"Many-worlds is an obvious fact, if you have all your marbles lined up correctly (understand very basic quantum physics, know the formal probability theory of Occam’s Razor, understand Special Relativity, etc.)"

2. ^

"The only question now is how long it will take for the people of this world to update." Both quotes from https://www.lesswrong.com/s/Kqs6GR7F5xziuSyGZ/p/S8ysHqeRGuySPttrS

Comment by anonymous_ea on On Deference and Yudkowsky's AI Risk Estimates · 2022-07-06T20:44:04.948Z · EA · GW

I’m trying to make sense of why you’re bringing up “overconfidence” here. The only thing I can think of is that you think that maybe there is simply not enough information to figure out whether MWI is right or wrong (not even for even an ideal reasoner with a brain the size of Jupiter and a billion years to ponder the topic), and therefore saying “MWI is unambiguously correct” is “overconfident”?

Here's my point: There is a rational limit to the amount of confidence one can have in MWI (or any belief). I don't know where exactly this limit is for MWI-extremism but Yudkowsky clearly exceeded it sometimes. To use made up numbers, suppose:

• MWI is objectively correct
• Eliezer says P(MWI is correct) = 0.9999999
• But rationally one can only reach P(MWI) = 0.999
• Because there are remaining uncertainties that cannot be eliminated through superior thinking and careful consideration, such lack of experimental evidence, the possibility of QM getting overturned, the possibility of a new and better interpretation in the future, and unknown unknowns.
• These factors add up to at least P(Not MWI) = 0.001.

Then even though Eliezer is correct about MWI being correct, he is still significantly overconfident in his belief about it.

Consider Paul's example of Eliezer saying MWI is comparable to heliocentrism:

If we are deeply wrong about physics, then I [Paul Christiano] think this could go either way. And it still seems quite plausible that we are deeply wrong about physics in one way or another (even if not in any particular way). So I think it's wrong to compare many-worlds to heliocentrism (as Eliezer has done). Heliocentrism is extraordinarily likely even if we are completely wrong about physics---direct observation of the solar system really is a much stronger form of evidence than a priori reasoning about the existence of other worlds.

I agree with Paul here. Heliocentrism is vastly more likely than any particular interpretation of quantum mechanics, and Eliezer was wrong to have made this comparison.

This may sound like I'm nitpicking, but I think it fits into a pattern of Eliezer making dramatic and overconfident pronouncements, and it's relevant information for people to consider e.g. when evaluating Eliezer's belief that p(doom) = ~1 and the AI safety situation is so hopeless that the only thing left is to die with slightly more dignity.

Of course, it's far from the only relevant data point.

Regarding (2), I think we're on the same page haha.

Comment by anonymous_ea on On Deference and Yudkowsky's AI Risk Estimates · 2022-07-05T22:38:12.706Z · EA · GW

When I said it was relevant to his track record as a public intellectual, I was referring to his tendency to make dramatic and overconfident pronouncements (which Ben mentioned in the parent comment). I wasn't intending to imply that the debate around QM had been settled or that new information had come out. I do think that even at the time Eliezer's positions on both MWI and why people disagreed with him on it were overconfident though.

I think you're right that my comment gave too little credit to Eliezer, and possibly misleadingly implied that Eliezer is the only one who holds some kind of extreme MWI or anti-collapse view or that such views are not or cannot be reasonable (especially anti-collapse). I said that MWI is a leading candidate but that's still probably underselling how many super pro-MWI positions there are. I expanded on this in another comment.

Your story of Eliezer comparing MWI to heliocentrism is a central example of what I'm talking about. It is not that his underlying position is wrong or even unlikely, but that he is significantly overconfident.

I think this is relevant information for people trying to understand Eliezer's recent writings.

To be clear, I don't think it's a particularly important example, and there is a lot of other more important information than whether Eliezer overestimated the case for MWI to some degree while also displaying impressive understanding of physics and possibly/probably being right about MWI.

Comment by anonymous_ea on On Deference and Yudkowsky's AI Risk Estimates · 2022-07-05T21:19:10.945Z · EA · GW

I agree that: Yudkowsky has an impressive understanding of physics for a layman, in some situations his understanding is on par with or exceeds some experts, and he has written explanations of technical topics that even some experts like and find impressive. This includes not just you, but also e.g. Scott Aaronson, who praised his series on QM in the same answer I excerpted above, calling it entertaining, enjoyable, and getting the technical stuff mostly right. He also praised it for its conceptual goals. I don't believe this is faint praise, especially given stereotypes of amateurs writing about physics. This is a positive part of Yudkowsky's track record. I think my comment sounds more negative about Yudkowsky's QM sequence than it deserves, so thanks for pushing back on that.

I'm not sure what you mean when you call yourself a pro-MWI extremist but in any case AFAIK there are physicists, including one or more prominent ones, who think MWI is really the only explanation that makes sense, although there are obviously degrees in how fervently one can hold this position and Yudkowsky seems at the extreme end of the scale in some of his writings. And he is far from the only one who thinks Copenhagen is ridiculous. These two parts of Yudkowsky's position on MWI are not without parallel within professional physicists, and the point about Copenhagen being ridiculous is probably a point in his favor from most views (e.g. Nobel laureate Murray Gell-Mann said that Neils Bohr brainwashed people into Copenhagen), let alone this community. Perhaps I should have clarified this in my comment, although I did say that MWI is a leading interpretation and may well be correct.

The negative aspects I said in my comment were:

1. Yudkowsky's confidence in MWI is disproportionate
2. Yudkowsky's conviction that people who disagree with him are making elementary mistakes is disproportionate
3. These may come partly from a lack of knowledge or expertise

Maybe (3) is a little unfair, or sounds harsher than I meant it. It's a bit unclear to me how seriously to take Aaronson's quote. It seems like plenty of physicists have looked through the sequences to find glaring flaws, and basically found none (physics stackexchange). This is a nontrivial achievement in context. At the same time I expect most of the scrutiny has been to a relatively shallow level, partly because Yudkowsky is a polarizing writer. Aaronson is probably one of fairly few people who have deep technical expertise and have read the sequences with both enjoyment and a critical eye. Aaronson suggested a specific, technical flaw that may be partly responsible for Yudkowsky holding an extreme position with overconfidence and misunderstanding what people who disagree with him think. Probably this is a flaw Yudkowsky would not have made if he had worked with a professional physicist or something. But maybe Aaronson was just casually speculating and maybe this doesn't matter too much. I don't know. Possibly you are right to push back on the mixed states explanation.

I think (1) and (2) are well worth considering though. The argument here is not that his position is necessarily wrong or impossible, but that it is overconfident. I am not courageous enough to argue for this position to a physicist who holds some kind of extreme pro-MWI view, but I think this is a reasonable view and there's a good chance (1) and (2) are correct. It also fits in Ben's point 4 in the comment above: "Yudkowsky’s track record suggests a substantial bias toward dramatic and overconfident predictions."

Comment by anonymous_ea on The Future Might Not Be So Great · 2022-07-05T16:48:09.065Z · EA · GW

For convenience, this is CEA's statement from three years ago:

We approached Jacy about our concerns about his behavior after receiving reports from several parties about concerns over several time periods, and we discussed this public statement with him. We have not been able to discuss details of most of these concerns in order to protect the confidentiality of the people who raised them, but we find the reports credible and concerning. It’s very important to CEA that EA be a community where people are treated with fairness and respect. If you’ve experienced problems in the EA community, we want to help. Julia Wise serves as a contact person for the community, and you can always bring concerns to her confidentially.

By my reading, the information about the reports contained in this is:

• CEA received reports from several parties about concerns over Jacy's behavior over several time periods
• CEA found the reports 'credible and concerning'
• CEA cannot discuss details of most of these concerns because the people who raised them want to protect their confidentiality
• It also implies that Jacy did not treat people with fairness and respect in the reported incidents
• 'It’s very important to CEA that EA be a community where people are treated with fairness and respect' - why say this unless it's applicable to this case?

Julia also said in a comment at the time that the reports were from members of the animal advocacy and EA communities, and CEA decided to approach Jacy primarily because of these rather than the Brown case:

The accusation of sexual misconduct at Brown is one of the things that worried us at CEA. But we approached Jacy primarily out of concern about other more recent reports from members of the animal advocacy and EA communities.

Comment by anonymous_ea on On Deference and Yudkowsky's AI Risk Estimates · 2022-07-04T01:13:02.134Z · EA · GW

Edit: I think this came off more negatively than I intended it to, particularly about Yudkowsky's understanding of physics. The main point I was trying to make is that Yudkowsky was overconfident, not that his underlying position was wrong. See the replies for more clarification.

I think there's another relevant (and negative) data point when discussing Yudkowsky's track record: his argument and belief that the Many-Worlds Interpretation of quantum mechanics is the only viable interpretation of quantum mechanics, and anyone who doesn't agree is essentially a moron. Here's one 2008 link from the Sequences where he expresses this position[1]; there are probably many other places where he's said similar things. (To be clear, I don’t know if he still holds this belief, and if he doesn’t anymore, when and why he updated away from it.)

Many Worlds is definitely a viable and even leading interpretation, and may well be correct. But Yudkowsky's confidence in Many Worlds, as well as his conviction that people who disagree with him are making elementary mistakes, is more than a little disproportionate, and may come partly from a lack of knowledge and expertise.

The above is a paraphrase of Scott Aaronson, a credible authority on quantum mechanics who is sympathetic to both Yudkowsky and Many Worlds (bold added):

I think Yudkowsky's central argument---basically, that anyone who rejects [Many Worlds] needs to have their head examined---is to put it mildly, a bit overstated. :) I'll resist the temptation to elaborate, since this is really a discussion for another thread.

In several posts, Yudkowsky gives indications that he doesn't really understand the concept of mixed states. (For example, he writes about the No-Communication Theorem as something complicated and mysterious, which it's not from a density-matrix perspective.) As I see it, this might be part of the reason why Yudkowsky sees anything besides Many-Worlds as insanity, and can't understand what (besides sheep-like conformity) would drive any knowledgeable physicist to any other point of view. If I didn't know that in real life, people pretty much never encounter pure states, but only more general objects that (to paraphrase Jaynes) scramble together "subjective" probabilities and "objective" amplitudes into a single omelette, the view that quantum states are "states of knowledge" that "live in the mind, not in the world" would probably also strike me as meaningless nonsense.

While this isn't directly related to AI risk, I think it's relevant to Yudkowsky's track record as a public intellectual.

1. ^

He expresses this in the last six paragraphs of the post. I'm excerpting some of it (bold added, italics were present in the original):

Many-worlds is an obvious fact, if you have all your marbles lined up correctly (understand very basic quantum physics, know the formal probability theory of Occam’s Razor, understand Special Relativity, etc.) It is in fact considerably more obvious to me than the proposition that spinning black holes should obey conservation of angular momentum.

...

So let me state then, very clearly, on behalf of any and all physicists out there who dare not say it themselves: Many-worlds wins outright given our current state of evidence. There is no more reason to postulate a single Earth, than there is to postulate that two colliding top quarks would decay in a way that violates Conservation of Energy. It takes more than an unknown fundamental law; it takes magic.

The debate should already be over. It should have been over fifty years ago. The state of evidence is too lopsided to justify further argument. There is no balance in this issue. There is no rational controversy to teach. The laws of probability theory are laws, not suggestions; there is no flexibility in the best guess given this evidence. Our children will look back at the fact that we were still arguing about this in the early twenty-first century, and correctly deduce that we were nuts.

We have embarrassed our Earth long enough by failing to see the obvious. So for the honor of my Earth, I write as if the existence of many-worlds were an established fact, because it is. The only question now is how long it will take for the people of this world to update.

Comment by anonymous_ea on The Future Might Not Be So Great · 2022-07-02T21:12:49.203Z · EA · GW

From Jacy:

this was only on my website for a few weeks at most... I believe I also casually used the term elsewhere, and it was sometimes used by people in my bio description when introducing me as a speaker.

Comment by anonymous_ea on On Deference and Yudkowsky's AI Risk Estimates · 2022-06-23T01:43:04.847Z · EA · GW

I don't necessarily disagree with the assessment of a temporary ban for "unnecessary rudeness or offensiveness", or "other behaviour that interferes with good discourse", but I disagree that Charles' comment quality is "uniformly" low or that a ban might be merited primarily because of high comment volume and too low quality.There are some real insights and contributions sprinkled in in my opinion.

For me the unnecessary rudeness or offensiveness and other behavior interfering with discourse comes from things like comments that are technically replies to a particular person but seem like they're mostly intended to win the argument in front of unknown readers, and containing things like rudeness, paranoia, and condescension towards the person they're replying to. I think the doxing accusation, which if I remember correctly actually doxxed the victim much more than Gwern's comment, is part of a similar pattern of engaging poorly with a particular person, partly through an incorrect assessment that the benefits to bystanders will outweigh the costs. I think this sort of behavior stifles conversation and good will.

I'm not sure a ban is a great solution though. There might be other, less blunt ways of tackling this situation.

What I would really like to see is a (much) higher lower limit of comment quality from Charles i.e. moving the bar for tolerating rudeness and bad behavior in a comment much higher even though it could be potentially justified in terms of benefits to bystanders or readers.

Comment by anonymous_ea on Some potential lessons from Carrick’s Congressional bid · 2022-05-19T03:29:31.952Z · EA · GW

The Reddit comments I've seen have been largely the same as well: people being tired of apparently incessant campaign ads along with some suspicion of large out of state money and crypto.

Comment by anonymous_ea on EA and the current funding situation · 2022-05-17T15:24:41.659Z · EA · GW

Comment by anonymous_ea on EA and the current funding situation · 2022-05-14T14:31:55.661Z · EA · GW

My read on your comment is that you misread Anthony's allusion to $1b as about potentially spending$1b at some stage (whether right now or later), rather than about the expected impact of his idea. I could be wrong, but that's the only way your comment makes sense to me ("if you spent $1b of EA money" - what could this refer to besides spending$1b of money?).

Anthony is asking for connection to someone who is skilled at running a particular kind of simulation to see if his idea has potential. He believes that the value of checking of his idea might be $1b, because of potentially trillions of dollars worth of gains. Crucially, it would not take$1b to check his idea - that figure is an estimate of the potential value of checking the idea, not of the cost of checking it. The cost of checking is probably something like the social capital to connect him with a relevant person and the costs involved in running the simulation (if it progresses to that stage).

I don't think this was a bad mistake on your end, just a quick, incorrect assumption that you made while trying to help someone. It only led to a fractious response because so many other EAs have also misread and misunderstood Anthony, and he is naturally tired and upset by this. In my opinion, the fault here lies mostly with social dynamics rather than any one person acting particularly badly.

I appreciate your attempts to engage productively (including deciding not to engage if that seems better to you), take responsibility for any mistakes you may have made, and without assigning blame to other parties. That is a clear positive to me.

Hope you have a good day as well :)

Comment by anonymous_ea on EA and the current funding situation · 2022-05-14T04:43:53.556Z · EA · GW

Upvoted for the last three sentences, but I believe your first sentence is incorrect. The second paragraph of your initial comment does not make sense to me in the absence of you believing that Anthony was looking for funding.

Comment by anonymous_ea on EA and the current funding situation · 2022-05-14T01:09:01.608Z · EA · GW

Thanks, this is a good followup. I'm glad my comment contained useful feedback for you.

I think your attempt to help Anthony went awry when he asked you why his tone was the bigger issue than whether he had been misrepresented, and you did not even seem to consider that he could be right in your reply. Perhaps he is right? Perhaps not? But it's important to at least genuinely consider that he could be.

Comment by anonymous_ea on EA and the current funding situation · 2022-05-14T00:21:50.675Z · EA · GW

Strong downvote for extreme and inappropriate condescension in the guise of helping someone. There is no adequate reason for you to assume that Anthony is living in a world where everyone is intrinsically against him, and that he cannot even imagine not living in a different world. This is an extremely strong statement to make about someone you know through a few online comments. Why do you think you're right?

Even if you were right, helping him would not take the form of trying to point this out publicly in such a tactless way.

Comment by anonymous_ea on An update in favor of trying to make tens of billions of dollars · 2022-05-11T12:38:42.216Z · EA · GW

Sorry, I don't have the capacity to engage further here.

Comment by anonymous_ea on An update in favor of trying to make tens of billions of dollars · 2022-05-10T02:38:51.209Z · EA · GW

I strongly disagree that the situational opportunity is anywhere near as broad as "mostly being an American alive in the 21st century". I'm not sure what you have in mind regarding "the type of person who is capable of starting the next FTX", but I think that is a fairly narrow class, not a very wide one.

Comment by anonymous_ea on An update in favor of trying to make tens of billions of dollars · 2022-05-10T01:54:52.176Z · EA · GW

Charles is not saying is that having an elite background is the only thing that matters. He is saying that high success involves both high capability and high situational opportunity.

Comment by anonymous_ea on Effective altruism’s odd attitude to mental health · 2022-04-30T00:35:33.110Z · EA · GW

Like IanDavidMoss says, I think the more interesting phenomenon you mention is the sudden and unnoticed switch to skeptical mode:

I then told them about my work at the Happier Lives Institute comparing the cost-effectiveness of cash transfers to treating depression and how we'd found the latter was about 10x better (original analysis, updated analysis). They suddenly switched to sceptical mode, saying they didn't believe you could really measure people's mental health or feelings and that, even if you could, targeting poverty must still be better.

After a couple of minutes of this, I suddenly clocked how weirdly disconnected the first and second parts of the conversation were. I asked them how they could be so sceptical of mental health as a global priority when they had literally just been talking to me about it as a very serious issue for EAs. They looked puzzled - the tension seemed never to have occurred to them - and, to their credit, they replied "oh, yeah, hmm, that is weird".

Comment by anonymous_ea on What is a neutral life like? · 2022-04-17T01:55:35.390Z · EA · GW

I don't buy that what a neutral life is like is an important question.

I listened to a few minutes of the timestamp you linked but unless I missed something, Will is talking about his interest in finding out what proportion of people have lives above and below zero, not what a neutral life is like.

Consider a life which, on bringing it into existence, neither increases nor decreases social welfare because it is perfectly neutral in quality. What is such a life like?

This is a hugely important question. For Effective Altruists, the answer has implications for the value of the far future and the relative importance of saving lives versus reducing suffering.

I don't see any tight connections between the value of finding out more about neutral lives and what implications that might have for efforts to reduce existential risk or other longtermist efforts. It's more related to the important question of saving lives vs reducing suffering, but I don't see any clear implications here either. If you spell out what connections you see I might be more convinced.

Even those not looking to improve the world should be interested - the answer also has implications for the ethics of having children and even whether or not you were wronged by being brought into existence. Despite this, the question has been given surprisingly little attention in both EA and non-EA circles.

It seems to me that the ethics of having children and the question of antinatalism are swamped by many considerations besides what a neutral life is like. Again, if you spell out the connections you see here I might be more interested.

I hope this is useful feedback!

Comment by anonymous_ea on Movement Collapse Scenarios · 2022-01-11T00:35:38.563Z · EA · GW

This is a great post in both content and writing quality. I'm a little sad that despite winning a forum prize, there was relatively little followup.

Comment by anonymous_ea on [Linkpost] Eric Schwitzgebel: Against Longtermism · 2022-01-07T00:11:41.289Z · EA · GW

Thanks for sharing this!

Quoting from the article (underline added):

First, it's unlikely that we live in a uniquely dangerous time for humanity, from a longterm perspective. Ord and other longtermists suggest, as I mentioned, that if we can survive the next few centuries, we will enter a permanently "secure" period in which we no longer face serious existential threats. Ord's thought appears to be that our wisdom will catch up with our power; we will be able to foresee and wisely avoid even tiny existential risks, in perpetuity or at least for millions of years. But why should we expect so much existential risk avoidance from our descendants? Ord and others offer little by way of argument.

[...]

You might suppose that, as resources improve, people will grow more cooperative and more inclined toward longterm thinking. Maybe. But even if so, cooperation carries risks. For example, if we become cooperative enough, everyone's existence and/or reproduction might come to depend on the survival of the society as a whole. The benefits of cooperation, specialization, and codependency might be substantial enough that more independent-minded survivalists are outcompeted. If genetic manipulation is seen as dangerous, decisions about reproduction might be centralized. We might become efficient, "superior" organisms that reproduce by a complex process different from traditional pregancy, requiring a stable web of technological resources. We might even merge into a single planet-sized superorganism, gaining huge benefits and efficiencies from doing so. However, once a species becomes a single organism the same size as its environment, a single death becomes the extinction of the species. Whether we become a supercooperative superorganism or a host of cooperative but technologically dependent individual organisms, one terrible miscalculation or one highly unlikely event could potentially bring down the whole structure, ending us all.

A more mundane concern is this: Cooperative entities can be taken advantage of. As long as people have differential degrees of reproductive success, there will be evolutionary pressure for cheaters to free-ride on others' cooperativeness at the expense of the whole. There will always be benefits for individuals or groups who let others be the ones who think longterm, making the sacrifices necessary to reduce existential risks. If the selfish groups are permitted to thrive, they could employ for their benefit technology with, say, a 1/1000 or 1/1000000 annual risk of destroying humanity, flourishing for a long time until the odds finally catch up. If, instead, such groups are aggressively quashed, that might require warlike force, with the risks that war entails, or it might involve complex webs of deception and counterdeception in which the longtermists might not always come out on top.

The point about cooperation carrying risks is interesting and not something I've seen elsewhere.

Comment by anonymous_ea on A huge opportunity for impact: movement building at top universities · 2021-12-26T15:56:34.438Z · EA · GW

Our Community Building Grants were a step up from an all-volunteer force of organizers, but we think they had some problems:

• We also didn’t spend enough time listening to and learning from organizers.

• What factors led to this happening?
• How did you realize you were making this mistake?
• What were the consequences of this mistake?
• How do you plan to rectify this in the future?
Comment by anonymous_ea on Aiming for the minimum of self-care is dangerous · 2021-12-11T20:06:27.319Z · EA · GW

On a similar note, I actually parsed the title as the opposite of the intended meaning. That is, I thought the article was going to say that aiming for the minimum [amount of impact, or something else related like career capital] is dangerous, rather than that that aiming for the minimal amount of self-care is dangerous.

Comment by anonymous_ea on A Primer on the Symmetry Theory of Valence · 2021-09-10T02:15:42.079Z · EA · GW

Greg, I want to bring two comments that have been posted since your comment above to your attention:

1. Abby said the following to Mike:

Your responses here are much more satisfying and comprehensible than your previous statements, it's a bit of a shame we can't reset the conversation.

2. Another anonymous commentator (thanks to Linch for posting) highlights that Abby's line of questioning regarding EEGs ultimately resulted in a response satisfactory to her and which she didn't have the expertise to further evaluate:

if they had given the response that they gave in one of the final comments in the discussion, right at the beginning (assuming Abby would have responded similarly) the response to their exchange might have been very different i.e. I think people would have concluded that they gave a sensible response and were talking about things that Abby didn't have expertise to comment on:

_______

Abby Hoskin: If your answer relies on something about how modularism/functionalism is bad: why is source localization critical for your main neuroimaging analysis of interest? If source localization is not necessary: why can't you use EEG to measure synchrony of neural oscillations?

Mike Johnson: The harmonic analysis we’re most interested in depends on accurately modeling the active harmonics (eigenmodes) of the brain. EEG doesn’t directly model eigenmodes; to infer eigenmodes we’d need fairly accurate source localization. It could be there are alternative ways to test STV without modeling brain eigenmodes, and that EEG could give us. I hope that’s the case, and I hope we find it, since EEG is certainly a lot easier to work with than fMRI.

Abby Hoskin: Ok, I appreciate this concrete response. I don't know enough about calculating eigenmodes with EEG data to predict how tractable it is.

Comment by anonymous_ea on AI Timelines: Where the Arguments, and the "Experts," Stand · 2021-09-08T13:26:34.579Z · EA · GW

I appreciate you posting this picture, which I had not seen before. I just want to add that this was compiled in 2014, and some of the people in the picture have likely shifted in their views since then.

Comment by anonymous_ea on Towards a Weaker Longtermism · 2021-08-09T19:46:54.828Z · EA · GW

Phil Trammell's point in  Which World Gets Saved is also relevant:

It seems to me that there is another important consideration which complicates the case for x-risk reduction efforts, which people currently neglect. The consideration is that, even if we think the value of the future is positive and large, the value of the future conditional on the fact that we marginally averted a given x-risk may not be.

...

Once we start thinking along these lines, we open various cans of worms. If our x-risk reduction effort starts far "upstream", e.g. with an effort to make people more cooperative and peace-loving in general, to what extent should we take the success of the intermediate steps (which must succeed for the x-risk reduction effort to succeed) as evidence that the saved world would go on to a great future? Should we incorporate the fact of our own choice to pursue x-risk reduction itself into our estimate of the expected value of the future, as recommended by evidential decision theory, or should we exclude it, as recommended by causal? How should we generate all these conditional expected values, anyway?

Some of these questions may be worth the time to answer carefully, and some may not. My goal here is just to raise the broad conditional-value consideration which, though obvious once stated, so far seems to have received too little attention. (For reference: on discussing this consideration with Will MacAskill and Toby Ord, both said that they had not thought of it, and thought that it was a good point.) In short, "The utilitarian imperative 'Maximize expected aggregate utility!'" might not really, as Bostrom (2002) puts it, "be simplified to the maxim 'Minimize existential risk'".

Comment by anonymous_ea on What EA projects could grow to become megaprojects, eventually spending $100m per year? · 2021-08-07T20:59:04.492Z · EA · GW I like this idea in general, but would it ever really be able to employ$100m+ annually? For comparison, GiveWell spends about $6 million/year and CSET was set up for$55m/5 years (11m/year)

Comment by anonymous_ea on Linch's Shortform · 2021-07-15T23:36:41.580Z · EA · GW

Thanks. Going back to your original impact estimate, I think the bigger difficulty I have in swallowing your impact estimate and claims related to it (e.g. "the ultimate weight of small decisions you make is measured not in dollars or relative status, but in stars") is not the probabilities of AI or space expansion, but what seems to me to be a pretty big jump from the potential stakes of a cause area or value possible in the future without any existential catastrophes, to the impact that researchers working on that cause area might have.

Comment by anonymous_ea on Linch's Shortform · 2021-07-05T21:09:47.563Z · EA · GW

So is the basic idea that transformative AI not ending in an existential catastrophe is the major bottleneck on a vastly positive future for humanity?

Comment by anonymous_ea on Linch's Shortform · 2021-07-05T16:50:03.495Z · EA · GW

Conditioning upon us buying the importance of work at MIRI (and if you don't buy it, replace what I said with CEA or Open Phil or CHAI or FHI or your favorite organization of choice), I think the work of someone sweeping the floors of MIRI is just phenomenally, astronomically important, in ways that is hard to comprehend intuitively.

(Some point estimates with made-up numbers: Suppose EA work in the next few decades can reduce existential risk from AI by 1%.  Assume that MIRI is 1% of the solution, and that there are less than 100 employees of MIRI. Suppose variance in how good a job someone can do in cleanliness of MIRI affects research output by 10^-4 as much as an average researcher.* Then we're already at 10^-2 x 10^ -2 x 10^-2 x 10^-4 = 10^-10 the impact of the far future. Meanwhile there are 5 x 10^22 stars in the visible universe)

Can you spell out the impact estimation you are doing in more detail? It seems to me that you first estimate how much a janitor at an org might impact the research productivity of that org, and then there's some multiplication related to the (entire?) value of the far future. Are you assuming that AI will essentially solve all issues and lead to positive space colonization, or something along those lines?

Comment by anonymous_ea on Looking for more 'PlayPumps' like examples · 2021-05-28T16:57:08.808Z · EA · GW

I'm not sure Make a Wish is a good example given the existence of this study. Quoting Dylan Matthews from Future Perfect on it (emphasis added):

The average wish costs $10,130 to fulfill. Given that Malaria Consortium can save the life of a child under 5 for roughly$2,000 (getting a precise figure is, of course, tough, but it’s around that), you could probably save four or five children’s lives in sub-Saharan Africa for the cost of providing a nice experience for a single child in the US. For the cost of the heartwarming Batkid stunt — $105,000 — you could save the lives of some 50-odd kids. So that’s why I’ve been hard on Make-A-Wish in the past, and why effective altruists like Peter Singer have criticized the group as well. But now I’m reconsidering. A new study in the journal Pediatric Research, comparing 496 patients at the Nationwide Children’s Hospital in Columbus, Ohio, who got their wishes granted to 496 “control” patients with similar ages, gender, and diseases, found that the patients who got their wishes granted went to the emergency room less, and were less likely to be readmitted to the hospital (outside of planned readmissions). In a number of cases, this reduction in hospital admissions and emergency room visits resulted in a cost savings in excess of$10,130, the cost of the average wish. In other words, Make-A-Wish helped, and helped in a cost-effective way.

Comment by anonymous_ea on Draft report on existential risk from power-seeking AI · 2021-05-08T21:02:21.863Z · EA · GW

This links to A Sketch of Good Communication, not whichever comment you were intending to link :)

Comment by anonymous_ea on Open and Welcome Thread: March 2021 · 2021-03-22T16:50:54.335Z · EA · GW

Welcome Sive!

Comment by anonymous_ea on Please stand with the Asian diaspora · 2021-03-22T13:55:01.636Z · EA · GW

Thanks for explaining. I don't wish to engage further here [feel free to reply though of course], but FWIW I don't agree that there are any reasoning errors in Jacob's post or any anomalies to explain. I think you are strongly focused on a part of the conversation that is of particular importance to you (something along the lines of whether people who are not motivated or skilled at expressing sympathy will be welcome here), while Jacob is mostly focused on other aspects.

Comment by anonymous_ea on Please stand with the Asian diaspora · 2021-03-21T22:33:12.693Z · EA · GW

what appears to me to be a series of anomalies that is otherwise hard to explain

What do you believe needs explaining?

Comment by anonymous_ea on Please stand with the Asian diaspora · 2021-03-21T17:15:18.516Z · EA · GW

This might be a minor point, but personally I think it's better to avoid making generalizations of how an entire community must be feeling. Some members of the Asian community are unaware of recent events, while others may not be particularly affected by them. Perhaps something more along the lines of "I understand many people in the Asian community are feeling hurt right now" would be generally better.

Comment by anonymous_ea on Please stand with the Asian diaspora · 2021-03-21T03:14:39.570Z · EA · GW

I'm curious how xccf's comment elsewhere on this thread fits in with your position as expressed here.

Comment by anonymous_ea on [deleted post] 2021-03-20T15:44:10.817Z

Ben Hoffman's GiveWell and the problem of Partial Funding was also posted here on the forum, with replies from OpenPhil and GiveWell staff.

Comment by anonymous_ea on [deleted post] 2021-03-19T19:09:45.330Z

I don't have any advice to offer, but as a datapoint for you: I applaud your goal and am even sympathetic to many of your points, but even I found this post actively annoying (unlike your previous ones in this series). It feels like you're writing a series of posts for your own benefit without actually engaging with your audience or interlocutors.  I think this is fine for a personal blog, but does not fit on this forum.

Comment by anonymous_ea on Religious Texts and EA: What Can We Learn and What Can We Inform? · 2021-01-30T16:08:26.958Z · EA · GW

There's a Buddhists in Effective Altruism group as well.

Comment by anonymous_ea on CEA update: Q4 2020 · 2021-01-15T22:54:59.758Z · EA · GW

Thanks for writing this!

Comment by anonymous_ea on Long-Term Future Fund: Ask Us Anything! · 2020-12-11T02:53:51.389Z · EA · GW

I think I would spend a substantial amount of money on prizes for people who seem to have done obviously really good things for the world. Giving $10M to scihub seems worth it. Maybe giving$5M to Daniel Ellsberg as a prize for his lifetime achievements. There are probably more people in this reference class of people who seem to me to have done heroic things, but haven't even been remotely well enough rewarded (like, it seems obvious that I would have wanted Einstein to die having at least a few millions in the bank, so righting wrongs of that reference class seems valuable, though Einstein did at least get a Nobel prize). My guess is one could spend another $100M this way. I'm really surprised by this; I think things like the Future of Life award are good, but if I got$1B I would definitely not think about spending potentially \$100m on similar awards as an EA endeavor. Can you say more about this? Why do you think this is so valuable?

Comment by anonymous_ea on Long-Term Future Fund: Ask Us Anything! · 2020-12-05T23:29:57.533Z · EA · GW

Regardless of whatever happens, I've benefited greatly from all the effort you've put in your public writing on the fund Oliver.

Comment by anonymous_ea on KevinO's Shortform · 2019-12-06T19:09:58.021Z · EA · GW

I just voted for the GFI, AMF, and GD videos because of your comment!


text:
## Scaling limits of particle systems on self-similar and random networks

###### (Click on each image for a high-res version.)

My research focuses on the analysis of probability models on self-similar and random graphs. The overarching goal is to prove limit theorems that describe various laws of nature that take place in fractal or random geometries, such as heat flow, wave propagation, charged particles in an electromagnetic field, and fluid dynamics.

I carry out two interconnected lines of research, one analytic and the other probabilistic. On the one hand, I analyze the eigenvalues and eigenfunctions of variants of the Laplace operator $$\Delta$$ on fractal spaces. On the other hand, I study the scaling limits of random processes involving many interacting particles driven by Laplacian-like operators, representing models of magnetism or crystal growth.

All of my research papers can be found on the arXiv.

## Recent papers

#### (Last updated March 2017)

NEW! Spherical asymptotics in the shape of internal DLA on Sierpinski gasket graphs. (An informal 1-sentence summary of this paper: "You can grow a crystal on a fractal, and yet the crystal will be round almost surely." Illustrated by the above animation.)

Power dissipation on the Feynman-Sierpinski ladder circuit and the Hanoi tower circuits. We give a "fractal spin" on the classic infinite ladder circuit discussed in the Feynman Lectures on Physics. For the F-S ladder we can rigorously prove the convergence of the effective impedances using the dynamics of Möbius transformations. This is just one example of how undergraduates can contribute to mathematical research. A refinement of our results (concerning the energy measure) on the F-S ladder circuit was attained recently by Patricia Alonso-Ruiz.

NEW! From non-symmetric particle systems to non-linear PDEs on fractals (a review). This is a summary of a series of preprints concerning the hydrodynamic limit of the boundary-driven exclusion process on a resistance space, which will appear in the near future. The starting point is:

The moving particle lemma for the exclusion process on a weighted graph. I prove in this paper an energy inequality for the exclusion process, which is analogous to Thomson's (or Dirichlet's) principle for random walks / electric networks. It builds upon the marvelous "octopus inequality" proved by Caputo, Liggett, and Richthammer in 2009.

Current Colgate student trainees: Jonah Kudler-Flam '17 and Ilias Stitou '19.

In Spring 2017, Jonah and Ilias are working on numerical simulations of aggregation models on fractal graphs, in an attempt to better understand the (fluctuations of the) limit shapes of the aggregate clusters. Their projects build upon the spherical shape theorem for internal DLA on the graphical Sierpinski gasket, proved recently by Huss, Sava-Huss, Teplyaev, and myself. Source codes will be made public upon the conclusion of the projects.

### Want to join my research group?

I'm always looking for bright, self-motivated, and mathematically inclined students to do research with me. Contrary to what you might have heard, it does not take a genius to do math research. With the right skill sets and persistence, anyone can contribute to the solution of an open mathematical problem.

For the past few years I have led projects that address open math questions via numerical experiments: By writing and running programs that numerically simulate the given problem, one produces results or pictures that suggest the existence of certain patterns, and then aims to justify their existence through rigorous proofs. Depending on your background and training, you may choose to focus on the theory, the numerics, or both.

My research problems are drawn from the intersection of probability, statistical physics, and theoretical computer science. In particular I like studying random (drunkard's) walks and the associated (discrete) calculus on various graphs, and then discover the appropriate limit theorems under a suitable space-time scaling. (Why take limits? Read about the infinite monkey theorem, and maybe you'll be convinced why taking limits is a good idea.)

My philosophy: I take a hands-on approach to supervising research. Roughly speaking, I meet with research students once a week, to discuss any issues they have come across and to debrief them on the necessary theory. Beyond the weekly meetings, it is up to the students to organize their own schedules to make progress. Usually I have some intuition about what the expected results may be, but I am also ready to be proven wrong if you can demonstrate accurate numerics (or even better, supported by proofs)! If you produce good results, I will encourage you to give conference presentations, and then (possibly) write a research paper (with me or on your own). (That way you'll have something to put on your resumé when applying for grad schools or jobs!)

Doing research is a highly NONLINEAR process: expect bruises and bumps (not literally, but figuratively) along the way. But don't easily give up: work hard, be persistently creative, and chances are that you will experience that moment of eureka!

Suggested preparation: I expect some level of mathematical maturity developed through coursework in math. Thus a (concurrent) background in linear algebra (MATH 214) is a bare minimum. Ideally I would look for someone who has further taken a course on mathematical proofs (MATH 250) and/or mathematical computations (MATH 260), plus a 300-level course that uses calculus actively, such as differential equations (MATH 308) and probability (MATH 316). A solid background in physics or CS is also desirable. (Extensive programming experience is a real plus!)

How to get involved? I anticipate hiring 2 students in each of Fall 2017 and Spring 2018 to work on projects TBA. (Unfortunately I'm not hiring in Summer 2017 due to my own travel schedule.) Look for the job posting in the Student Employment section of the Colgate portal approximately 4 weeks prior to the start of the semester. Apply through the portal; be sure to describe your previous course and research experience. Successful candidates will be notified shortly before the start of the semester. (You can choose to work with me for either \$ or credit through independent study, but not both.)

I am also happy to provide informal advice on attacking problems coming from mathematical analysis (real & complex), probability & stochastic processes, and mathematical physics (quantum mechanics & statistical mechanics).

## Recent & upcoming professional travel

During the academic year, I often attend the analysis seminar and the probability seminar at the Cornell math department.

March 2017: Seminar on Stochastic Processes, University of Virginia. (Contributed talk)

April 2017: Hudson River Undergraduate Mathematics Conference, Westfield State University (Westfield, MA). (Contributed talk)

April 2017: Finger Lakes Probability Seminar, Syracuse University. (Contributed talk)

May-June 2017: Research stay at Institut Henri Poincaré, Paris. Thematic quarter program "Stochastic Dynamics out of Equilibrium."

June 2017: 6th Cornell Conference on Analysis, Probability, and Mathematical Physics on Fractals, Cornell University. (Conference co-organizer)

July 2017: International Workshop on BSDEs, SPDEs and their Applications, University of Edinburgh. (Invited talk at special session)

July-August 2017: Research stay at Bielefeld University, Germany, sponsored in part by the Bielefeld-Seoul IRTG 2235. (Planned lectures TBA)

September 2017: Northeast Analysis Network Conference, Syracuse University.

## Conference & seminar organization

June 13-17, 2017: Bob Strichartz, Sasha Teplyaev, Luke Rogers and I are organizing the 6th Cornell Conference on Analysis, Probability, and Mathematical Physics on Fractals.

March 19-20, 2016: Bob Strichartz, Sasha Teplyaev, Luke Rogers and I organized a special session at the AMS Spring Eastern Sectional Meeting at SUNY Stony Brook.

From Spring 2015 to Spring 2016, Matthew Badger and I co-organized the UConn Analysis & Probability Seminar, Fridays 3:15-4:15p.

In Summer 2015, I was one of the research mentors for the UConn math REU program, working mainly with the fractals group and the stochastic control group. I also organized the summer S.I.G.M.A. seminar (Fridays 12:15p~1:15p).

On July 28, 2015, Luke Rogers and I co-organized the 3rd Northeast Mathematics Undergraduate Research Mini-Symposium.

## Funding

JPC's current and recent past research has been supported in part by the National Science Foundation (DMS-1262929) and the Research Council of Colgate University (discretionary grant, student wage grant, and a major grant for 2017~18).

Back to JPC's homepage

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text:
# contour integration: $\int_{-\infty}^{\infty} \frac{\cos x + x \sin x}{1+x^2} dx$

I'm doing a self-study in learning contour integration in complex analysis and here's an example i came across:

$$\int_{-\infty}^{\infty} \frac{\cos x + x \sin x}{1+x^2} dx$$

How does this relate to the following integral over a semi-circle in the upper half plane ($0\leq t \leq \pi$)?

$$\int_{R e^{it}} \frac{e^{iz}}{z-i} dz$$

(This came from a hint in our notes)

-

Note that $$f(z) = \frac{e^{iz}}{z-i} = \frac{(z+i)e^{iz}}{(z+i)(z-i)} = \frac{(z+i)e^{iz}}{z^2+1}.$$

So, if $z=x$ is real, then $$f(x) = \frac{(x+i)(\cos x + i \sin x)}{x^2+1} = \frac{x\cos x - \sin x + i(\cos x + x\sin x)}{x^2+1}.$$

Let $\Gamma$ be the closed curve consisting of the interval $[-R,R]$ together with the semi-circle $C : z=Re^{it}$, $0 < t < \pi$ (for $R > 1$). By the residue theorem,

$$\int_{\Gamma} f(z)\,dz = \int_{[-R,R]} f(z)\,dz + \int_C f(z)\,dz = 2\pi i \operatorname{Res}(f;z=i)$$

(since $z=i$ is the only singularity of $f$ inside $\Gamma$). Finally, let $R\to\infty$.

The integral over $C$ will tend to $0$ by Jordan's lemma, and you will end up with

$$\int_{-\infty}^\infty \frac{x\cos x - \sin x}{x^2+1}\,dx + i \int_{-\infty}^\infty \frac{x\sin x + \cos x}{x^2+1}\,dx = 2\pi i \operatorname{Res}(f;z=i).$$

To finish off, compute the residue and look at the imaginary part of the equality above.

-
Just a caution: Since a priori we don't know whether this integral, we indeed need to choose a slight different contour, a rectangle on the upper half plane, for details, see P 156, 3) in the book "complex analysis" by Ahlfors, which deals with the case with simple zero at infinity. –  Lao-tzu Jan 12 at 8:33


text:
## Electronic Journal of Probability

### Reconstructing a Multicolor Random Scenery seen along a Random Walk Path with Bounded Jumps

#### Abstract

Kesten noticed that the scenery reconstruction method proposed by Matzinger in his PhD thesis relies heavily on the skip-free property of the random walk. He asked if one can still reconstruct an i.i.d. scenery seen along the path of a non-skip-free random walk. In this article, we positively answer this question. We prove that if there are enough colors and if the random walk is recurrent with at most bounded jumps, and if it can reach every integer, then one can almost surely reconstruct almost every scenery up to translations and reflections. Our reconstruction method works if there are more colors in the scenery than possible single steps for the random walk.

#### Article information

Source
Electron. J. Probab., Volume 9 (2004), paper no. 15, 436-507.

Dates
Accepted: 15 May 2004
First available in Project Euclid: 6 June 2016

Permanent link to this document
https://projecteuclid.org/euclid.ejp/1465229701

Digital Object Identifier
doi:10.1214/EJP.v9-206

Mathematical Reviews number (MathSciNet)
MR2080606

Zentralblatt MATH identifier
1064.60201

Subjects
Primary: 60K37: Processes in random environments
Secondary: 60G10: Stationary processes 60J75: Jump processes

Rights
This work is licensed under aCreative Commons Attribution 3.0 License.

#### Citation

Loewe, Matthias; Matzinger, Heinrich; Merkl, Franz. Reconstructing a Multicolor Random Scenery seen along a Random Walk Path with Bounded Jumps. Electron. J. Probab. 9 (2004), paper no. 15, 436--507. doi:10.1214/EJP.v9-206. https://projecteuclid.org/euclid.ejp/1465229701

#### References

• Benjamini, Itai; Kesten, Harry. Distinguishing sceneries by observing the scenery along a random walk path. J. Anal. Math. 69 (1996), 97–135.
• Burdzy, Krzysztof. Some path properties of iterated Brownian motion. Seminar on Stochastic Processes, 1992 (Seattle, WA, 1992), 67–87, Progr. Probab., 33, Birkhäuser Boston, Boston, MA, 1993.
• den Hollander, Frank; Steif, Jeffrey E. Mixing properties of the generalized $T,T^{-1}$-process. J. Anal. Math. 72 (1997), 165–202.
• den Hollander, W. Th. F. Mixing properties for random walk in random scenery. Ann. Probab. 16 (1988), no. 4, 1788–1802.
• Durrett, Richard. Probability: theory and examples. Second edition. Duxbury Press, Belmont, CA, 1996. xiii+503 pp. ISBN: 0-534-24318-5
• Howard, C. Douglas. Detecting defects in periodic scenery by random walks on $Z$. Random Structures Algorithms 8 (1996), no. 1, 59–74.
• Howard, C. Douglas. Orthogonality of measures induced by random walks with scenery. Combin. Probab. Comput. 5 (1996), no. 3, 247–256.
• Howard, C. Douglas. Distinguishing certain random sceneries on $Z$ via random walks. Statist. Probab. Lett. 34 (1997), no. 2, 123–132.
• Kalikow, Steven Arthur. $T,T^{-1}$ transformation is not loosely Bernoulli. Ann. of Math. (2) 115 (1982), no. 2, 393–409.
• Keane, M.; den Hollander, W. Th. F. Ergodic properties of color records. Phys. A 138 (1986), no. 1-2, 183–193.
• Kesten, Harry. Detecting a single defect in a scenery by observing the scenery along a random walk path. Itô's stochastic calculus and probability theory, 171–183, Springer, Tokyo, 1996.
• Lenstra, Andries; Matzinger, Heinrich. Reconstructing a 4-color scenery by observing it along a recurrent random walk path with unbounded jumps. In preparation (2004).
• Lindenstrauss, Elon. Indistinguishable sceneries. Random Structures Algorithms 14 (1999), no. 1, 71–86.
• Löwe, Matthias; Matzinger, Heinrich, III. Scenery reconstruction in two dimensions with many colors. Ann. Appl. Probab. 12 (2002), no. 4, 1322–1347.
• Löwe, Matthias; Matzinger, Heinrich, III. Reconstruction of sceneries with correlated colors. Stochastic Process. Appl. 105 (2003), no. 2, 175–210.
• Löwe, Matthias; Matzinger, Heinrich, III. Reconstructing a three-color scenery by observing it along a simple random walk path. Random Structures Algorithms 15 (1999), no. 2, 196–207.
• Matzinger, Heinrich; Rolles, Silke W. W. Finding blocks and other patterns in a random coloring of Z. Preprint no. 03-044 in http://www.mathematik.uni-bielefeld.de/fgweb/Preprints/index03.html (2003).
• Matzinger, Heinrich; Rolles, Silke W. W. Reconstructing a piece of scenery with polynomially many observations. Stochastic Process. Appl. 107 (2003), no. 2, 289–300.
• Matzinger, Heinrich; Rolles, Silke W. W. Reconstructing a random scenery observed with random errors along a random walk path. Probab. Theory Related Fields 125 (2003), no. 4, 539–577.
• Matzinger, Heinrich; Rolles, Silke W. W. Retrieving random media. Preprint no. 03-043 in http://www.mathematik.uni-bielefeld.de/fgweb/Preprints/index03.html (2003).
• Spitzer, Frank. Principles of random walks. Second edition. Graduate Texts in Mathematics, Vol. 34. Springer-Verlag, New York-Heidelberg, 1976. xiii+408 pp.


text:
# Lesson 9

La diferencia entre números

### Lesson Purpose

The purpose of this lesson is for students to represent and compare different subtraction methods on the number line.

### Lesson Narrative

In previous lessons, students represented addition and subtraction equations on the number line and wrote equations to match representations on a number line.

In this lesson, students deepen their understanding of subtraction as taking from and as an unknown addend problem. Students represent subtraction methods on the number line and compare how each representation shows the difference. The number line is also used to help students visualize when counting on and counting back strategies may be useful when subtracting 2 two-digit numbers. For example, $$17 - 14$$ can be solved by starting at 17 and counting back 14. It can also be solved by starting at 14 and counting on 3. In this case, counting on would likely be helpful because the numbers are close together and the structure of the number line helps show why this strategy is effective (MP7).

• Action and Expression

### Learning Goals

Teacher Facing

• On a number line, represent counting on and counting back strategies for solving subtraction equations.

### Student Facing

• Representemos formas de restar en la recta numérica.

### Required Materials

Materials to Gather

Materials to Copy

• Number Line to 100

### Required Preparation

Activity 1:

• Place the number line recording sheets in sheet protectors. They will be used in the next activity and future lessons.

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

Which students had opportunities to share their diagrams and thinking during whole-class discussion? How did you select these students?

### Suggested Centers

• Number Puzzles: Addition and Subtraction (1–4), Stage 4: Within 100 with Composing (Addressing)
• Number Line Scoot (2–3), Stage 1: Twos, Fives, and Tens (Addressing)


text:
# Can this problem be modelled with a transformation from a known TSP with profits?

The profitable tour problem (PTP) is defined on a graph $$G=(V,E)$$ with $$|V|=n$$, where each vertex $$i \in V$$ has an associated prize $$m_i \geq 0$$ and each edge $$e \in E$$ has an associated cost $$c_e \geq 0$$. The problem asks to find a subset of vertices and a tour visiting them, maximising the difference between prizes collected and travel costs paid. Let $$\mathbf{y} \in \{0,1\}^n$$ be a vector whose $$i$$-th entry is 1 iff vertex $$i \in V$$ is included in the tour, and let $$\text{TSP}(\mathbf{y})$$ denote the cost of the shortest tour over the vertices included by $$\mathbf{y}$$. Furthermore denote the vector of profits as $$\mathbf{m} = (m_1, \ldots, m_n)$$. Then one can write the PTP as:

$$\max_{\mathbf{y} \in \{0,1\}^n} \big\{ \mathbf{m}^\intercal \mathbf{y} - \text{TSP}(\mathbf{y}) \big\}$$

I have a problem which is, in some informal sense, dual to the PTP. My problem can be written as follows:

$$\max_{\mathbf{y} \in \{0,1\}^n} \big\{ \text{TSP}(\mathbf{y}) - \mathbf{m}^\intercal \mathbf{y} \big\}$$

In other words, I am looking for a subset of vertices of $$V$$ over which the shortest tour is longest but, to include a vertex $$i$$ in my tour, I have to pay a penalty $$m_i$$.

I have been thinking about it for a while, but I feel like the opposite optimisation direction between the outer maximisation problem and the inner minimisation (hidden in $$\text{TSP}$$) makes it hard to tackle this problem simply with a transformation from an existing TSP with profits, such as the PTP.

Am I missing something obvious? Is there a straightforward transformation to a well-known problem that I don't see?

• Out of curiosity, is this a real life problem ? – Kuifje Jun 3 '20 at 9:40
• @Kuifje in some sense... solving it would give a bound on a real-life problem. – Alberto Santini Jun 3 '20 at 9:41
• I need some time to think about it, but have you thought of transformation from a known TSP by setting the costs $c_{ij}$ to $-c_{ij}$ (in order to have a min TSP problem)? – Kuifje Jun 3 '20 at 9:42
• Initially I thought about that, but I discarded the idea because I thought it was bound to find longest tours in the inner TSP problem, not shortest. I might be wrong, though... I will think more about it. – Alberto Santini Jun 3 '20 at 10:14
• I understand the confusion might have arisen from me using the "longest TSP" terminology. I didn't mean that the problem asks for the longest hamiltonian tour. I edited the question and I hope it's clearer now. – Alberto Santini Jun 4 '20 at 6:39


text:
# Quickstart¶

## Launching detectEr from the shell¶

The detecter/ebin directory created previously needs to be included in the Erlang runtime path to preload all the binaries required to be able to use detectEr. This is done by using the -pa switch when launching the Erlang shell.

[duncan@local]:$erl -pa /path/to/detecter/ebin  Once loaded, detectEr can be used to monitor systems that execute on the Erlang Virtual Machine. It also supports the monitoring of systems that run outside of the EVM, provided that these record their logs in files following a predetermined formatting that enables detectEr to extract runtime information. This topic is covered in more depth in the Instrumentation section. For now, we establish the workflow required to use detectEr by way of the traditional ‘hello world’ example. ## Hello world¶ Before using detectEr, you should get an intuitive grasp of what monitoring is, and the steps one needs to follow to initialise and start the monitoring process. If this is your first time using Erlang, the following wil help you get acquainted with the Erlang shell. Launch a new terminal emulator window (e.g. Terminal on Ubuntu or macOS), navigate to the root detectEr directory, and: 1. Change the directory to examples/erlang. [duncan@local]:/detecter$ cd examples/erlang
[duncan@local]:/detecter/examples/erlang$ls -l -rw-rw-r-- 1 duncan duncan 996 May 17 17:16 Makefile drwxrwxr-x 2 duncan duncan 4096 May 17 17:16 props drwxrwxr-x 3 duncan duncan 4096 May 17 17:16 src  2. Execute make to compile all of the Erlang source code modules located in examples/erlang/src. A new ebin directory containing the compiled *.beam files is created. BEAM files are (fairly) portable binaries consisting of bytecode that is interpreted by the EVM, similar to how Java operates. [duncan@local]:/detecter/examples/erlang$ make
rm -f ebin/*.beam ebin/*.E ebin/*.tmp erl_crash.dump ebin/*.app
...
[duncan@local]:/detecter/examples/erlang$ls -l -rw-rw-r-- 1 duncan duncan 996 May 17 17:16 Makefile drwxrwxr-x 7 duncan duncan 224 May 17 17:16 ebin drwxrwxr-x 2 duncan duncan 4096 May 17 17:16 props drwxrwxr-x 3 duncan duncan 4096 May 17 17:16 src  3. Launch the Erlang shell erl. We add the binaries of the ebin directory to the Erlang code path via the -pa flag to load and make them accessible from the shell. [duncan@local]:/detecter/examples/erlang$ erl -pa ebin
Erlang/OTP 23 [erts-11.2.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe] [dtrace]
Eshell V11.2.1  (abort with ^G)
1>

4. The Erlang shell allows you to type expressions and execute them by pressing Enter. Every expression typed on the shell must be terminated with a full-stop. Try invoking the function greet of the hello module. The function greet accepts one argument, the name of the person to greet, specified as a string enclosed within double quotes.

1> hello:greet("Duncan").
Hello there, Duncan!
ok
2>

5. Quit the Erlang shell by typing q().

Function signatures

In Erlang (and Elixir), functions are uniquely identified via the triple mod:fun/arity, where mod is the module name, fun, the name of the function contained in the module, and arity, the number of arguments that the function accepts. This reference format is commonly known as MFA. For example, our greet function inside the module hello can be concisely referred to as hello:greet/1. We refer to functions in the same module simply as fun/arity.

## Hello world, the asynchronous way¶

You might have noticed that hello:greet/1 pauses the Erlang shell momentarily before the greeting is displayed. During this interval, the shell is inoperable and cannot accept user input. Such function calls are called synchronous invocations, since they block the caller until the called function returns, i.e. the body of the called function is executed in its entirety and a value is returned to the caller. Examining the body of greet below makes it clear why the Erlang shell stops responding when the function call is effected.

 1 2 3 greet(Name) -> timer:sleep(5000), % Pause for 5 seconds to simulate some work.. io:format("Hello there, ~s!~n", [Name]).

Line 1 defines the function greet that accepts Name as parameter, while line 3 prints the greeting on the Erlang shell via call to io:format/2. The call timer:sleep(5000) on line 2 pauses the caller process (i.e. the Erlang shell, in this case) for 5000 ms before executing the rest of the function body. In Erlang, the function return value is the result of the last expression in the function body; for the case of greet, this value is the atom ok that is returned by io:format/2.

Synchronous calls

Synchronous function calls are useful when one needs to ensure that certain processes execute in some prescribed order with respect to one another, e.g. in lock step. This mode of interaction is common to many standard communication protocols such as HTTP, SMTP, DNS, etc.

Unwanted synchrony can be easily avoided by launching functions to execute as independent processes that run concurrently with other processes in the system. To this end, Erlang provides the Built-in Functions spawn/{1-4}, and their variations. We slightly tweak our hello world example to spawn hello:greet/1 as a separate process that executes concurrently with the Erlang shell process.

 4 5 start_greet(Name) when is_list(Name) -> spawn(?MODULE, greet, [Name]).

The function start_greet/1 implements this modification. It uses the BIF spawn/3 (line 5) to launch hello:greet/1 as a process, returning the new process ID. Process IDs (PIDs for short) are triples of the form <A.B.C> that uniquely identify Erlang processes executing on the EVM. spawn/3 is parametrised by the module name, the name of the function to spawn, and the list of arguments accepted by the function. Function start_greet/1 makes use of the predefined macro ?MODULE, that gets replaced with the name of the module it appears in when the source code of the hello module is preprocessed by the Erlang compiler. Concretely, the invocation to spawn/3 on line 5 yields the source code spawn(hello, greet, [Name]) prior to compilation.

Restart the Erlang shell and invoke hello:start_greet/1.

1> hello:start_greet("Duncan").
<0.97.0>
Hello there, Duncan! % Shown after a slight pause.
2>

Observe that now:

1. The return value of start_greet is the PID of the spawned process <0.97.0> instead of the atom ok;

2. The Erlang shell does not block, but returns immediately;

3. After the predefined sleep time elapses, the greeting is printed to the shell.

## Outline runtime monitoring¶

In this quickstart demo, we monitor the execution of our asynchronous hello world example using the outline form of instrumentation.

1. Launch the shell as previous, adding the hello world binaries in ebin to the Erlang code path. The detectEr binaries compiled earlier are also included.

[duncan@local]:/detecter/examples/erlang\$ erl -pa ebin ../../detecter/ebin
Erlang/OTP 23 [erts-11.2.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe] [dtrace]
Eshell V11.2.1  (abort with ^G)
1>

2. Compile the sample prop_hello.hml property script to generate the corresponding analyser binary.

1> hml_eval:compile("props/prop_hello.hml", [{outdir,"ebin"}, v]).

This compilation procedure, known as the synthesis, translates sHML specifications written in *.hml script files to their analyser equivalents. For now, it suffices to know that sHML—the logic used by detectEr—expresses properties of the system one wishes to runtime verify. Our analyser Erlang binary generated from the sample property is placed in /detecter/examples/erlang/ebin and automatically loaded for use in the shell code path.

2> ls("ebin").
hello.beam
prop_hello.beam
...

The analyser prop_hello exposes a single function, mfa_spec/1, that accepts the MFArgs triple {Mod, Fun, Args} designating the Erlang process to be analysed. Specifically, Mod, Fun and Args are the components of the function passed as arguments to spawn/3. For our hello world example, Mod is the atom hello, Fun is the function name greet, and Args, the singleton argument list containing the name of the person to be greeted. You can test prop_hello:mfa_spec/1 analyser function by providing the triple {hello, greet, ["Duncan"]}.

3> prop_hello:mfa_spec({hello, greet, ["Duncan"]}).
*** [<0.82.0>] Instrumenting monitor for MFA pattern '{hello, greet, ["Duncan"]}'.
*** [<0.82.0>] Reached verdict 'no'.

3. Launch the monitored system.

4> monitor:start_online({hello, start_greet, ["Duncan"]}, fun prop_hello:mfa_spec/1, []).

The function monitor:start_online/3 accepts three arguments: a MFArgs describing the function that is to be spawned as an Erlang process, the analyser function, and a list of options. Setting MFArgs to {hello,start_greet,["Duncan"]} and the analyser to fun prop_hello:mfa_spec/1 launches the hello world and analyser processes to execute concurrently.

In this introductory example, the analyser prop_hello promptly terminates with the verdict no as soon as our hello world program starts executing. The no verdict informs us that a program has violated the specification of prop_hello.hml.

We next look at a typical concurrent program where processes interact, and study what kind of useful properties one might want such systems to observe.


text:
# Copying content from Excel into PowerPoint as a picture, with error handling

The code below works, but I want to ask if my solution is adequate or if there's something I should structure differently. If it's alright, I'll apply the same code in other subs.

My code copies stuff from Excel to PowerPoint and inserts it as a picture. In order to do this, I first have to copy data from one part of the sheet into a specific range. This range is where the summary and chart draw their input from. I then copy the summary and chart for each VW into PowerPoint. The one issue that persists is that the line mySlide.Shapes.PasteSpecial DataType:=ppPasteEnhancedMetafile frequently gives me an error: "Error -2147188160 Shapes (unknown member): invalid request. The specified data type is unavailable." I had this issue in other files appear as well but was solved by using DoEvents and Application.CutCopyMode = False.

Neither helped in this case, so my next best idea is to let VBA retry copy-pasting until it works (up to 20, so it doesn't get stuck in an endless loop). I'm new to error handling and this is what I came up with (it's a sub called from the main procedure); I marked the 4 labels/GoTo statements:

Public PowerPointApp As PowerPoint.Application
Public myPresentation As PowerPoint.Presentation
Public myShape As PowerPoint.Shape
Public mySlide As PowerPoint.Slide

'in main sub:
'Set PowerPointApp = New PowerPoint.Application
'Set myPresentation = PowerPointApp.Presentations.Open("C:\....")

Sub SubSlide4(wsKAP As Worksheet, RangeArray As Variant)
'RangeArray = = Array("Range1", "Range2", "Range3"...)
Dim iSlide As Long
Dim rngVW As Variant
Dim fullNameVW As String
Dim ErrorCount4 As Long

iSlide = 4
ErrorCount4 = 0
For Each rngVW In RangeArray 'RangeArray has ~10 members

'Paste correct data for each VW
wsKAP.Range(rngVW).Copy
fullNameVW = "Test"
wsKAP.Range("C73") = fullNameVW

Set mySlide = myPresentation.Slides(iSlide)

'Copying Summary for each VW
Set rng = wsKAP.Range("C89:P97")
rng.Copy
DoEvents
mySlide.Shapes.PasteSpecial DataType:=ppPasteEnhancedMetafile
Set myShape = mySlide.Shapes(mySlide.Shapes.Count)
With myShape
.Left = 20
.Top = 71
.Height = 92
End With

'Copying Charts
RepeatOnError: '<-----------------------------------------------------
Set rng = wsKAP.Range("A30:Y69")
rng.Copy
DoEvents
On Error GoTo ErrorHandler '<-----------------------------------
mySlide.Shapes.PasteSpecial DataType:=ppPasteEnhancedMetafile
Set myShape = mySlide.Shapes(mySlide.Shapes.Count)
With myShape
.Left = 20
.Top = 187
.Width = 686
End With
iSlide = iSlide + 1
Application.CutCopyMode = False
Next rngVW

ErrorHandler: '<----------------------------------------------------------
If Err.Number = -2147188160 Then
If ErrorCount4 > 20 Then
MsgBox "Too many errors (-2147188160), canceling"
End
End If

ErrorCount4 = ErrorCount4 + 1
Debug.Print "ErrorCount4 is " & ErrorCount4
Resume RepeatOnError '<-----------------------------------------
End If
On Error GoTo 0
End Sub

So whenever error -2147188160 occurs, it should jump back to 'RepeatOnError' and try copy-pasting it once again. So far this has worked, but I wonder if this is the VBA way to go about error handling.

Someone on Stack Overflow suggested I need to use Exit Sub before the error handler— is that true?

• This is the article you should read. rubberduckvba.wordpress.com/2019/05/09/pattern-tryparse. You should also put 'Option Explicit' at the top of your module as you seem to have undeclared variables (myShape?). You might also install Rubberduck for the code inspections feedback. – Freeflow May 23 at 9:10


text:
Requests for technical support from the VASP group should be posted in the VASP-forum.

# Category:Ensemble properties

In a molecular-dynamics calculation, VASP simulates a specific ensemble. In principle, any property of the system can be monitored, and then one can take the ensemble average of this property. For some observables, VASP provides convenient tags, articles, and files that help evaluate these so-called ensemble properties.

## Theory

For any property ${\displaystyle {\mathcal {A}}}$ of the system, we can define the observable macroscopic property ${\displaystyle {\mathcal {A}}_{\mathrm {obs} }}$ by taking the ensemble average:

${\displaystyle {\mathcal {A}}_{\mathrm {obs} }=\left\langle {\mathcal {A}}\left(p(t),q(t)\right)\right\rangle _{\mathrm {time} }=\lim _{t_{\mathrm {obs} }\to \infty }{\frac {1}{t_{\mathrm {obs} }}}\int _{0}^{t_{\mathrm {obs} }}\,{\mathcal {A}}\left(p(t),q(t)\right)\,\mathrm {d} t.}$

Here, ${\displaystyle t_{\mathrm {obs} }}$ corresponds to the simulation time, ${\displaystyle p(t)}$ and ${\displaystyle q(t)}$ are the canonical momenta and positions, and an average of ${\displaystyle {\mathcal {A}}\left(p(t),q(t)\right)}$ is taken over time ${\displaystyle t}$.

## Pages in category "Ensemble properties"

The following 3 pages are in this category, out of 3 total.


text:
## Replacing Numerical Columns using pandas

I’m looking to replace the values of 2 specific columns (not including the header) of a data file that I have with randomly generated values. I already have the random values defined and now I’m looking to replace the columns of the original file with these new values. Each has 251 entries so it would be hard to identify each column individually.

import numpy as np import matplotlib.pyplot as plt import pandas as pd from pandas import DataFrame import os

X=np.asarray(np.loadtxt('/~/vh1/tdsw1.init',skiprows=1)).T

Corresponding columns

Radius = X[1] R1=Radius+1 Velocity = X[2] Density = X[3] MVelocity = Velocity*(1+0.2*np.random.randn(len(Velocity))) MDensity = Density*(1+0.2*np.random.randn(len(Density)))

Now I want to replace Velocity and Density with MVelocity and MDensity

data = pd.read_csv("/Users/dylanhilligoss/vh1/tdsw1MD.init",header=None) data.replace(to_replace=Velocity,value=MVelocity) data.replace(to_replace=Density,value=MDensity) print(data)

The output is the exact same file that I originally called in. Does anyone have any suggestions?

## Replacing a non-basepoint free line bundle by a basepoint free one

In his paper “Brill-noether-petri without degenerations”, Lazarsfeld says the following in in Corollary 1.4.

Statement – Assume that every member of the linear series $$|C_0|$$ in a K3 surface is reduced and irreducible. Then for every smooth curve $$C$$ in the linear system and every line bundle $$A$$ on $$C$$, one has $$\rho(A)\geq 0$$ where $$\rho(A)=g(C)-h^0(A)h^1(A)$$.

Proof: Let $$B$$ be a special globally general line bundle on a smooth curve $$C$$. If $$B^*\otimes\omega_C$$ has base divisor $$\Delta$$, then $$B(\Delta)$$ is again basepoint free. Thus we can assume in the statement that both $$A$$ and $$A^*\otimes \omega_C$$ are globally generated.

I don’t understand the above.

1) First of all, how to prove that $$B(\Delta)$$ is basepoint free?

2) Now $$B(\Delta)$$ and $$\omega_C\otimes B^*(-\Delta)$$ are globally generated. But how does that imply the statement for $$B$$? In other words why is it enough to check for line bundles of the form $$B(\Delta)$$?

3) In the proof of the main theorem, it says (from the above remark) if $$D$$ is any effective divisor on $$C$$ and $$\Delta$$ is the divisor of basepoints of $$|D|$$, then the injectivity of the Petri map $$\mu_0$$ for $$O_C(D-\Delta)$$ implies the injectivity of $$\mu_0$$ for $$O_C(D)$$? Why is this?

Grateful for any help!

## GRUB4DOS error after installing Kubuntu 19.04 and replacing GRUB with Windows 10 Bootloader on Dualboot

I’m getting the following error enter image description here

[enter image description here][2]

I followed instructions from this video: https://www.youtube.com/watch?v=GaCbTe1eEes

## Refactoring: Replacing a temporary variable with a query. Is this code example bad practice?

Before I ask my question, I want to note that this is not my own code; it comes from the Refactoring Guru website:

I often find myself using the code on the left, and I have one primary motivation for doing so: in the code on the right, you are unnecessarily pushing and popping a stack frame for the same operation twice in a row. For example, suppose that the base price is in fact greater than 1000. In testing this conditional, you already computed what the base price is… So by the time you get to the body of that conditional, you already know the value, and there’s really no point in re-computing it with a second call to basePrice(). In either case—when the base price exceeds 1000 or is less than or equal to 1000—you end up with an extra redundant call to basePrice().

Question: Does the code on the right offer any real advantages over the one on the left? The site mentions that this allows for greater reusability of the code in case other methods want to compute the base price as well, which I agree with.

## Refactoring: Replacing a temporary variable with a query. Is this code example bad practice?

Before I ask my question, I want to note that this is not my own code; it comes from the Refactoring Guru website (note that I’ve tagged this question as relating to C because I could not find a tag for refactoring/code cleanliness/style):

I often find myself using the code on the left, and I have one primary motivation for doing so: in the code on the right, you are unnecessarily pushing and popping a stack frame for the same operation twice in a row. For example, suppose that the base price is in fact greater than 1000. In testing this conditional, you already computed what the base price is… So by the time you get to the body of that conditional, you already know the value, and there’s really no point in re-computing it with a second call to basePrice(). In either case—when the base price exceeds 1000 or is less than or equal to 1000—you end up with an extra redundant call to basePrice().

Question: Does the code on the right offer any real advantages over the one on the left? The site mentions that this allows for greater reusability of the code in case other methods want to compute the base price as well, which I agree with.

## Stern’s diatomic series fusc: replacing #define functions with two return values

I have a function to review which implements Stern’s diatomic series fusc for a single word (ulong = unsigned long) in place, as a part of an arbitrary-precision implementation. In fact, there’s just one part of it that’s bothering me, though I’d be happy to get feedback on any of it, of course.

I have a (pseudofunction) define fusc8bits which ‘returns’ two values. It works, but I’d rather do this some other way. As this is a performance-critical function any replacements will need to keep this requirement in mind. Alternatively, and unexpectedly, a reviewer might say that my approach is actually a good one.

Unfortunately the arrays are used by other functions, so they can’t be pulled inside the function. (I wish they weren’t so visually imposing, though.)

static const ulong fuscAA[] = {   1,  8,  7,  13, 6,  17, 11, 16, 5,  19, 14, 23, 9,  22, 13, 17, 4,  19, 15,   26, 11, 29, 18, 25, 7,  24, 17, 27, 10, 23, 13, 16, 3,  17, 14, 25, 11, 30,   19, 27, 8,  29, 21, 34, 13, 31, 18, 23, 5,  22, 17, 29, 12, 31, 19, 26, 7,   23, 16, 25, 9,  20, 11, 13, 2,  13, 11, 20, 9,  25, 16, 23, 7,  26, 19, 31,   12, 29, 17, 22, 5,  23, 18, 31, 13, 34, 21, 29, 8,  27, 19, 30, 11, 25, 14,   17, 3,  16, 13, 23, 10, 27, 17, 24, 7,  25, 18, 29, 11, 26, 15, 19, 4,  17,   13, 22, 9,  23, 14, 19, 5,  16, 11, 17, 6,  13, 7,  8,  1,  7,  6,  11, 5,   14, 9,  13, 4,  15, 11, 18, 7,  17, 10, 13, 3,  14, 11, 19, 8,  21, 13, 18,   5,  17, 12, 19, 7,  16, 9,  11, 2,  11, 9,  16, 7,  19, 12, 17, 5,  18, 13,   21, 8,  19, 11, 14, 3,  13, 10, 17, 7,  18, 11, 15, 4,  13, 9,  14, 5,  11,   6,  7,  1,  6,  5,  9,  4,  11, 7,  10, 3,  11, 8,  13, 5,  12, 7,  9,  2,   9,  7,  12, 5,  13, 8,  11, 3,  10, 7,  11, 4,  9,  5,  6,  1,  5,  4,  7,   3,  8,  5,  7,  2,  7,  5,  8,  3,  7,  4,  5,  1,  4,  3,  5,  2,  5,  3,   4,  1,  3,  2,  3,  1,  2,  1,  1 }; static const ulong fuscAB[] = {   8,  7,  13, 6,  17, 11, 16, 5,  19, 14, 23, 9,  22, 13, 17, 4,  19, 15, 26,   11, 29, 18, 25, 7,  24, 17, 27, 10, 23, 13, 16, 3,  17, 14, 25, 11, 30, 19,   27, 8,  29, 21, 34, 13, 31, 18, 23, 5,  22, 17, 29, 12, 31, 19, 26, 7,  23,   16, 25, 9,  20, 11, 13, 2,  13, 11, 20, 9,  25, 16, 23, 7,  26, 19, 31, 12,   29, 17, 22, 5,  23, 18, 31, 13, 34, 21, 29, 8,  27, 19, 30, 11, 25, 14, 17,   3,  16, 13, 23, 10, 27, 17, 24, 7,  25, 18, 29, 11, 26, 15, 19, 4,  17, 13,   22, 9,  23, 14, 19, 5,  16, 11, 17, 6,  13, 7,  8,  1,  7,  6,  11, 5,  14,   9,  13, 4,  15, 11, 18, 7,  17, 10, 13, 3,  14, 11, 19, 8,  21, 13, 18, 5,   17, 12, 19, 7,  16, 9,  11, 2,  11, 9,  16, 7,  19, 12, 17, 5,  18, 13, 21,   8,  19, 11, 14, 3,  13, 10, 17, 7,  18, 11, 15, 4,  13, 9,  14, 5,  11, 6,   7,  1,  6,  5,  9,  4,  11, 7,  10, 3,  11, 8,  13, 5,  12, 7,  9,  2,  9,   7,  12, 5,  13, 8,  11, 3,  10, 7,  11, 4,  9,  5,  6,  1,  5,  4,  7,  3,   8,  5,  7,  2,  7,  5,  8,  3,  7,  4,  5,  1,  4,  3,  5,  2,  5,  3,  4,   1,  3,  2,  3,  1,  2,  1,  1,  0 }; static const ulong fuscBA[] = {   0,  1,  1,  2,  1,  3,  2,  3,  1,  4,  3,  5,  2,  5,  3,  4,  1,  5,  4,   7,  3,  8,  5,  7,  2,  7,  5,  8,  3,  7,  4,  5,  1,  6,  5,  9,  4,  11,   7,  10, 3,  11, 8,  13, 5,  12, 7,  9,  2,  9,  7,  12, 5,  13, 8,  11, 3,   10, 7,  11, 4,  9,  5,  6,  1,  7,  6,  11, 5,  14, 9,  13, 4,  15, 11, 18,   7,  17, 10, 13, 3,  14, 11, 19, 8,  21, 13, 18, 5,  17, 12, 19, 7,  16, 9,   11, 2,  11, 9,  16, 7,  19, 12, 17, 5,  18, 13, 21, 8,  19, 11, 14, 3,  13,   10, 17, 7,  18, 11, 15, 4,  13, 9,  14, 5,  11, 6,  7,  1,  8,  7,  13, 6,   17, 11, 16, 5,  19, 14, 23, 9,  22, 13, 17, 4,  19, 15, 26, 11, 29, 18, 25,   7,  24, 17, 27, 10, 23, 13, 16, 3,  17, 14, 25, 11, 30, 19, 27, 8,  29, 21,   34, 13, 31, 18, 23, 5,  22, 17, 29, 12, 31, 19, 26, 7,  23, 16, 25, 9,  20,   11, 13, 2,  13, 11, 20, 9,  25, 16, 23, 7,  26, 19, 31, 12, 29, 17, 22, 5,   23, 18, 31, 13, 34, 21, 29, 8,  27, 19, 30, 11, 25, 14, 17, 3,  16, 13, 23,   10, 27, 17, 24, 7,  25, 18, 29, 11, 26, 15, 19, 4,  17, 13, 22, 9,  23, 14,   19, 5,  16, 11, 17, 6,  13, 7,  8 }; static const ulong fuscBB[] = {   1,  1,  2,  1,  3,  2,  3,  1,  4,  3,  5,  2,  5,  3,  4,  1,  5,  4,  7,   3,  8,  5,  7,  2,  7,  5,  8,  3,  7,  4,  5,  1,  6,  5,  9,  4,  11, 7,   10, 3,  11, 8,  13, 5,  12, 7,  9,  2,  9,  7,  12, 5,  13, 8,  11, 3,  10,   7,  11, 4,  9,  5,  6,  1,  7,  6,  11, 5,  14, 9,  13, 4,  15, 11, 18, 7,   17, 10, 13, 3,  14, 11, 19, 8,  21, 13, 18, 5,  17, 12, 19, 7,  16, 9,  11,   2,  11, 9,  16, 7,  19, 12, 17, 5,  18, 13, 21, 8,  19, 11, 14, 3,  13, 10,   17, 7,  18, 11, 15, 4,  13, 9,  14, 5,  11, 6,  7,  1,  8,  7,  13, 6,  17,   11, 16, 5,  19, 14, 23, 9,  22, 13, 17, 4,  19, 15, 26, 11, 29, 18, 25, 7,   24, 17, 27, 10, 23, 13, 16, 3,  17, 14, 25, 11, 30, 19, 27, 8,  29, 21, 34,   13, 31, 18, 23, 5,  22, 17, 29, 12, 31, 19, 26, 7,  23, 16, 25, 9,  20, 11,   13, 2,  13, 11, 20, 9,  25, 16, 23, 7,  26, 19, 31, 12, 29, 17, 22, 5,  23,   18, 31, 13, 34, 21, 29, 8,  27, 19, 30, 11, 25, 14, 17, 3,  16, 13, 23, 10,   27, 17, 24, 7,  25, 18, 29, 11, 26, 15, 19, 4,  17, 13, 22, 9,  23, 14, 19,   5,  16, 11, 17, 6,  13, 7,  8,  1 };  #define fusc8bits(a, b, idx)                                                   \   {                                                                            \     int i = (idx)&0xFF;                                                        \     int newA = a * fuscAA[i] + b * fuscAB[i];                                  \     b = a * fuscBA[i] + b * fuscBB[i];                                         \     a = newA;                                                                  \   } static void fusc_word(ulong u, ulong* a, ulong* b) {   *a = fuscAA[u & 0xFF];   *b = 0;   fusc8bits(*a, *b, u >> 8) fusc8bits(*a, *b, u >> 16)     fusc8bits(*a, *b, u >> 24) #ifdef LONG_IS_64BIT       fusc8bits(*a, *b, u >> 32) fusc8bits(*a, *b, u >> 40)         fusc8bits(*a, *b, u >> 48) fusc8bits(*a, *b, u >> 56) #endif }

so basically I’m having an old HP laptop that has an Intel Pentium CPU N3700 @1.6GHz, has 4GB of RAM, 64-bit OS and runs Windows 10. I’m trying to replace that windows 10 with Ubuntu so I don’t if anyone that has experience about this can help me out. Thank you. It would be nice if anyone can share any good tutorial link for this. Please excuse my bad English.

## Vertical lines on the left side of iphone 4s after it fell down. Can it be fixed without replacing its screen?

I accidentally dropped my iphone 4s and vertical lines have appeared on the left side. Although, the screen did not break. The screen works well but i can’t see the other side of the screen and i am struggling. Can it be fixed without the need to replace the screen? I tried to shut it down and open it it didn’t work. And i tried a method i saw on youtube where i would go to settings then ringtones and would play the ringtone and close and open the screen it did not work either. Please help me. Thank you

## Is it possible to exploit XSS by replacing image data for img tag

If I have HTML page served over https with image loaded over http (image from other domain):

<img src="https://some-image.png"/>

so it’s possible to inject any data to browser as image by using MITM attack. Is it possible to inject some Javascript code instead of image or maybe wrap some code to SVG image to execute this code in browser? Or the only risk is that someone can replace one image with another?

## Replacing a specific users content creation with the newest version in views

I’m creating a website that tracks users weight. A user can create content to enter their weight and I have a view that displays all entries of a users weight however I want it so that if a user makes two entries on a single day that only the most recent from that day is shown and all the rest are not.

I have tried limiting the date but no success.


text:
Does balancing the training data set distribution for a neural network affect its understanding of the original distribution of data?

I have a very imbalanced dataset of two classes: 2% for the first class and 98% for the second. Such imbalance does not make training easy and so balancing the data set by undersampling class 2 seemed like a good idea.

However, as I think about it, should not the machine learning algorithm expect the same data distribution in nature as in its training set? I know, for sure, that the distribution of data in nature matches my imbalanced dataset. Does that mean that the balanced dataset will negatively affect the neural net performance with testing? when it assumed a different distribution of data caused by my balanced data set.

This is a very good question. Your problem is the classic classification problem of Neural Networks. In this problem the main objective of the Neural Network is to transform the data by some non-linear (in general) transformation so that the data becomes linearly separable for the final layer to perform classification.

Point to Note: This is not a regression problem, so that you are trying to fit a curve. Whenever there is a regression problem logically you can use a PDF to write some kind of information about new data. You can express mathematically the probability of your data falling within a certain range of error, since this is a optimising continuous function problem (generally RMSE).

This is not in the case of classifier. Classifier follow Bernoulli probability (though we represent the cost function as continuous). So current event is independent of past events. This makes a classifier harder to train for unbalanced class. So if we write:

func foo(data):
return True

It pretty much has 98% accuracy, but you can understand we do not want this type of classifier.

In general we want both classes to have good accuracy scores, sometimes this is measured by $F1_{score}$ but I like to think it in terms of proportionality. If we have $n$ examples with $m$ in one class, then and the classifier $a_1$ and $a_2$ correct predictions in both classes respectively, then I would check both the metric $\frac {a_1}{m}$ and $\frac {a_2}{n-m}$, which gives you the general idea.

Also in practical the identification 2% is sometimes far more important than the rest 98% (air-plane defects, cancer detection). So we use special ML algorithm called Anomaly Detectors for such type of problems.

• Side note: I have tried to use mathematical terms to convey my general idea. Due to my unfamiliarity with mathematical terms the interpretation might turn out to be wrong. Feel free to point out errors or inconsistencies. – DuttaA Sep 17 '18 at 12:36


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Have you recently come across a term referred to as, “CBD”? If so, it has recently become a topic of interest. In particular, many consumers across the globe have been considering Cannabidiol (CBD), a non-psychoactive portion of Cannabis that has a large range of therapeutic benefits as an alternative to prescription drugs, as it is natural and has been found to house multiple healing properties. The purpose of this review is to examine Organi Farm’s approach to CBD consumption, which has been reflected in the Herbal Relief CBD Oil. Here’s a brief analysis of what’s been shared thus far.

## What is Organi Farm Herbal Relief CBD Oil?

Herbal Relief is a CBD oil created by Organi Farm. While the source of hemp used in the formula has yet to be revealed, it supposedly contains 750 mg of CBD per 30 ml (i.e. roughly 25mg per ml) and comes in a mint flavor. In addition, it is said to contain no traces of THC – making it a pure CBD solution. When it comes to its potential results, consumers can anticipate a 97% reduction in anxiety and stress, 67% increase in cognitive performance and a 43% increase in antioxidant support to the body, along with improvements for chronic pains, hypertension, and insomnia issues.

### What is the Herbal Relief Trial Offer?

Organi Farm’s Herbal Relief CBD Oil is currently being offered as a 14 day rush trial. This simply implies that consumers can try the oil over the course of 14 days prior to paying the amount in full.

Should the oil meet one’s expectations at the end of the 14 day free trial, the company will then make a charge of $89.95USD to the consumers credit card, with monthly supplies shipped and payments made. If one decides to cancel their subscription, this should be done a day prior to the end of the 14 day trial period. If the consumer chooses not to cancel then, every thirty (30) days after the trial period, the company will automatically charge another$89.65 USD to your account. In the case the consumer cancels the customer service will issue a Return Merchandise Authorization (“RMA”) number. The consumer will be responsible for paying all costs related to shipping the trial supply back to us using the RMA number.

### Contacting Organi Farm Herbal Relief CBD Oil customer service?

To contact customer service, consumers can either email them at support@tryorganifarm.com or by calling 1 (855) 700-1839.

## Organi Farm Herbal Relief CBD Oil Final Thoughts

Organi Farm appears to have created a CBD oil that is above standards. This is solely based on the 750mg of CBD that consumers will be getting per bottle. As for its original price of $89.95, this seems to be reasonable, as similar concentrations of CBD are accessible between$69.99 and \$140.99. That said, a major concern with Organi Farm is their level of transparency.

Neither the source of hemp used nor proof of lab-testing (i.e. Certificate of Analysis) have been provided. These alone are indicative of what an individual is investing in, especially during a time where CBD and marijuana laws aren’t stable. Finally, strong claims have been made in terms of potential results, but once again, evidence is lacking. Hence, consumers should clarify their doubts and concerns prior to making a purchase.