... because of the way MongoDB actually stores records and parses them. It is more or less a simple tree or linked list, and hence doing almost anything involves decending branches to the leaves. This is horrendously inefficient in many contexts, while still being perfectly lovely in others. Just doing a match, though, can involve a non-polynomial time search. Maybe they've improved this from when I was trying to use Mongo to drive modelling, but I doubt it as it would have involved substantially changing the way the data is actually stored and dereferenced. I had to cheat substantially in order to get anything like decent performance, and any of the SQLs outperformed it handily.

Note well that it was strictly a scaling issue. For small trees and DBs, it probably works well enough. For large DBs with millions of records and substantial structure, it is like molasses. Only worse.

rgb

I had a friend who had a Benjamin, actually, but this was back in the 60's, and yes, I was jealous as I had only a .177 break-action pellet rifle. Speciality pellet that had, as you note, a muzzle velocity "comparable" to a 22 short. Yes (Google being Our Friend), 22 LR is 1200 fps (for a reason!), a 22 short is around 1000 fps, and a Benjamin is (usually, dependent on model and mechanism) 900, which is quite respectable but depends on pellet weight.

When I decided as an Old Guy to get a really good hunting class pellet rifle I looked hard at the Benjamin-Sheridans but ended up picking the Walther Falcon Hunter edition, which is also 900 fps and fires a variety of standard or "hunting class" .22 pellets. I actually haven't tried to fire it through a 4x4 -- but who knows? I got it for my sons (really, my youngest son who is the most avid hunter) and it drops a rabbit as readily as a 22. I'm guessing that a hollow point pellet would quite possibly kill a deer shot at reasonably close range (10 yards or so and a heart or perfect head shot) -- as a 22 might -- or for that matter a human. I doubt it would "drop" either one, though and this is something I would never try with either rifle, of course, unless it is after the apocalypse and it is kill a deer with the pellet rifle or go hungry:-). In the old days I saw for myself that a daisy BB gun would leave a very painful divot in human skin without quite penetrating (no, I did not pull that particular trigger). You would not try that with the Walther as it would go clean through your leg if it didn't hit the bone, and would have a pretty good chance of chipping or breaking the bone.

The Walther, in other words, like the Benjamin Marauder etc, is definitely not a toy gun. I also have an older .177 caliber pellet gun that fires a pellet slowly enough that you can "see" it (barely) en route and one doesn't fire it at a plywood sheet as it might bounce back (or more likely, embed itself 3 mm into the wood). No comparison.

Bear in mind that it isn't just muzzle velocity, it is mass. A .22 LR is typically a 40 grain bullet, a .22 short is around 30 grain, compared to a "standard" .22 pellet at 14.3 grains and speciality hunting pellets at 20 to as much as 40 grains). The .22 LR has around 5x the kinetic energy of almost any pellet rifle out of the bore and that's a simple fact. Finally, it is ballistic drag. Pellets generally aren't fired fast enough to get sufficient stability from rifling and spin to be particularly accurate, which accounts for their "diabolo" waist. This also produces substantial drag -- it is being stabilized by drag. This means that pellet rifles have a rapid dropoff of their muzzle velocity and are really only suitable for short range hunting for any sort of larger game. Real .22 rifles get enough spin that they can avoid the skirted diabolo design, avoid much of the drag, and still have equal or better precision and ballistics. The third issue is the sound barrier. That's the thing that limits .22 muzzle velocity even in the case of the rifle -- there is substantial turbulence as a bullet passes through the sound barrier slowing down, and one needs streamlined bullet shapes like those found in centerfire rifles (which do indeed fire even .22-ish caliber highly streamlined and much more massive bullets with muzzle velocities well over the speed of sound) to have decent ballistics. Rimfire .22 LR bullets are not streamlined and are designed to shoot just under the speed of sound (or in the case of 1200 fps almost instantly drop down under it as the bullet "settles" out of the barrel) so that they usually have decent but not impressive precision (bench grouping). Competition grade guns (rimfire or pellet) usually shoot bullets at muzzle velocities deliberately well under the speed of sound -- .22 shorts, not long rifles, for example. The needs of hunters -- high muzzle velocity at a substantial pellet mass, decent ballistics, high bullet energy -- are not always compatible with maximum precision at range. 900 fps .22 is a decent compromise, but the Benjamin Marauder (which absolutely is a very high end hunting class rifle) can come in a .25 caliber and can fire much heavier pellets. I have 20 grain pellets for the Walther -- I am guessing that they drop my muzzle velocity some but not too much -- and CAN get much heavier pellets, basically up to 40 grains, equivalent to shooting a .22 LR bullet out of the pellet gun. At that mass, however, the muzzle velocity would be substantially lower. Good perhaps for high precision target shooting at shortish ranges or game at those ranges, not so good for 30 to 50 yard shots. But then, pellet rifles are rarely particularly "good" for shots longer than 30 yards.

At 900 fps one has a wide range of "hunting" class rifles with similar muzzle energies to choose from, that are all going to have very similar ballistics and penetration capabilities at similar ranges, because most of the stuff that happens is pure physics. You can pay more for features -- especially precision-enhancing features or precompression, as those things require more engineering. The Walther isn't the most expensive hunting class rifle made, but it is a damn good intermediate one and, if you look around with Google, a very popular one for good reason. One could argue that it is one of the best values out there -- basically the same muzzle velocity as the Benjamin and other very high end guns, extraordinarily good stability and balance, simple mechanics and capable of high precision (small grouping) at 20-30 yards (it is actually a break action rifle -- single spring pump) and very high reliability. With a 20 grain hollow point pellet at 20 yards, easily the match of any small game including foxes or racoons or groundhogs (none of which we would likely shoot where I live) and perfect for rabbits and squirrels or birds.

rgb

...Or, \pi R^2 = 3 x 400 \approx 1200 square meters of collector area (concentrated down by the mirrors). If so, the collector surface receives around 1.2 MW peak, or at 80% efficiency 960 KW converted. The 12 KW is therefore not conceivably peak, it has to be a 24 hour average -- 12*24 = 288 KW-hr, which assumes peak can be (nearly) maintained for close to 8 hours a day. This completely changes the numbers. 288 KW-hr/day is $43/day at $0.15 KW-hour, and allowing for (say) 200 days a year effective production at this rate a ROI of anywhere from $8000/year to as much as $12000. That would amortize a $100,000 installation cost in a decade allowing for the cost of the money, and yield profits thereafter. That is actually pretty competitive with passive solar, which also has an amortization time of around a decade or bit more for consumers, although power companies probably beat that pretty substantially with their improved economies of scale. If the other "benefits" from using the water cooled system (nice trick, turning a waste heat liability almost anywhere into an "asset" add value, amortization is correspondingly lowered. Forests of these things in North Africa bordering the Mediterranean, for example, could conceivable power rapid economic development of the region while simultaneously watering the Sahara and conceivably actually altering its climate with progressive anti-desertification, while paying for themselves and even yielding a healthy long term ROI.

If they really mean 12 KW peak, then this is of course ridiculous, but that can't be right as ordinary passive PV could easily generate 120 KW peak, if not 240 KW peak with current technology, from the same 1200 m^2, and with tracking could accomplish an almost identical efficiency profile at 10 year amortization.

The top article was sufficiently messed up unitwise that I'm guessing that the author was simply clueless about this stuff. The missing number, of course, is the cost per installation. If it is less than $100K and produces an average of 288 KW-hours/day, they could range from break even with existing technology to very attractive even without "water" or "cooling" or "heating" advantages (that could easily be liabilities in locations where water for cooling is itself expensive or ecologically restricted). If it is more, well, it's an instant non-starter until they get the price down. But I'm guessing one could build these things for $100K and make money -- the concrete itself is order of $10K to $20K (including the mirrors), say $10K for the PV collector and cooling, $10K for the electronics and tracking, $30K for labor and installation -- $30K to $40K for profit at a 40% or so margin? And improvable with mass production? But I wouldn't be surprised if it were $250 K. Or $80K.

The latter is a complete waste of time. The former makes them a game changer, at least for a few years before passive PV overtakes them and renders the entire energy "crisis" moot by dropping amortization and ROI for consumer rooftop installations from around a decade plus a decade of "profit" to less than seven years and thirteen or more years of "profit". We're already on the edge of where installing rooftop solar on all new construction houses and rolling the cost into the primary mortgage is a no-brainer: "Buy a house and never pay for electricity... (for the next 20 years)" for an extra 10 or 20 thousand in price on a $250K house. Inside a decade, I fully expect to see this happen without any prodding in all parts of the US with adequate annual insolation just because it makes economic sense -- we need just one more factor of two reduction in the cost per watt of 20 year installed solar. For power companies, the amortization/ROI is largely already there in many parts of the US, and they are happily building solar farms wherever they can get cheap land near expensive electricity.

rgb

In fact, my high end .22 pellet rifle can almost certainly penetrate a skull. It goes through 5/8" plywood with ease. Certainly at the thin spots -- through the eyes, the temple -- but I certainly wouldn't bet my life that it wouldn't make it through even the thicker parts. And it's more like a .22 short or long, not even a LR in terms of muzzle velocity.

Possibly. But if it is a 2*poodle*pi, it is probably disk shaped, possibly with delicately scalloped edges. A spherical poodle seems more likely to be a (4/3)*pi*poodle-cubed, and if nothing else, being cubed is very hard on poodles. Often they subsequently turn into e^{-poodle}, a decaying poodle or (if eaten) into ex-poodle-poo.

rgb

And then there is Susskind and Black Hole Wars. In a sense, quantum mechanics already has shown that black holes in the classic sense do not exist. At least there is no entropic disconnect or loss of information.

But that is all theoretical stuff, and since we cannot really directly observe an event horizon, the best that we can say is that we can observe very distant objects that meet the mass criterion for having such a thing, if in fact the theories that predict them are correct. But an object with that same mass but no actual event horizon would, I think, look almost exactly the same from far away as far all that we can see, radiation from infalling superheated particles, is concerned. Do they pass an event horizon or asymptotically approach an almost-event horizon that never quite forms without ever technically reaching it? We'd have to capture one and examine it up close as we shot things in to -- maybe -- be able to tell the difference.

But it makes a huge difference to field theories and the effort to resolve reversible information-conserving quantum mechanics and irreversible information destroying singularities.

rgb

As long as we don't have to add 4*poodle*pi, I'm happy. I doubt even a single poodle would taste very good in pi.

Other than that, I get

\Delta C = C' - C = 2\pi(R+\Delta R) - 2\pi R = 2\pi \Delta R

where \Delta R is one standard poodle, which is (curiously enough) 0.314159 meters when converted into metric. That is, a one tenth of a pi poodle.

rgb

I spent around a year with it on at least a few of the systems I use. But I have G2 hotwired to cycle windows, open xterms, switch desktops, and fully use its autohide bars which are already laid out with everything I need and little that I don't. I do most of my work in either a browser or xterms, but I have that work in many different subjects with several windows open per subject spread out over 6 desktops that are a keystroke away. G3's window switching mechanism when I used it was arcane and enormously slow in comparison.

The real problem is that while a fork was perhaps needed, they did it wrong. G2 was close to perfect for what it was designed to do -- if nothing else its flaws were all flaws we all had worked around, and it had/has (I'm still using it, personally) some really nice features. Forking off a tablet version of Gnome is just peachy, but it should have been a TABLET VERSION fork, not an abandonment of the mainstream, widely deployed G2 in favor of a tablet friendlier interface that was enormously clunky on a non-tablet desktop or even laptop.

Sometimes there is change because it is needed, sometimes there is change for the sake of change. I sadly think that G3 is ten parts of the latter for one part of the former. Change involves pain either way, but at least one can see some advantage to doing so.

What exactly are the advantages -- not the places where yeah, with work and possibly more slowly you can make it function but actual advantages -- of G3, in particular advantages that one couldn't have implemented just as easily as new features of G2 without necessarily breaking old features that were heavily in use?

I'm not seein' a lot of those. I can launch any application I want under G2 with a key combination, for every application I ever launch, and don't even use that feature any more for anything but xterms because I use a lot of those to do work in. Window )cycling and desktop switching, though, those I use all of the time. Miniapps and application bar launchers, I use those. I don't care about animation. I don't need finger swipe screens. I don't need to have to work to find applications listed in a neat sorted order, or to have to change "views" to access certain features. I login (rarely), pop a single instance of firefox up, and from then on most of what I do is either browser based or xterm based, and I can pop an xterm up with Ctrl-Alt-P in far less than 1 second on the fly, then cycle up through a whole stack of windows with Ctrl-Shift-F to the one I want, then jump to desktop 6 (F6) to set up some music, then back to desktop 3 (F3) to work on something I'm writing, and then...

Maybe I can do all of this (and preserve the macros etc) in Mate. I suppose I should give it a try, maybe in a VM or something. Heck, maybe I'll install a full fedora VM to try it again -- I think I have the room. I used to use Fedora all the time before G3, but it was a serious show stopper.

rgb

Gnome 2 as an option (by whatever name) or only the insanity of windowing systems designed for finger-picking-tablets forced upon keystroke oriented users of actual computers doing real work in many windows on several desktops?

Otherwise, Centos 6 may end up being the last release I ever use. G2 may or may not be perfect, but I've got it more comfortable than five year old denim jeans and G3 sucked and continues to suck and AFAICT will continue to suck, forever, amen.

rgb

Kirk? Spock? Metaphor?

Atheists do not believe in God, because there is no sound evidence for God and atheists do not believe in things without evidence. Scientists tend not to believe in things without evidence, God is a thing one could believe in, so absent evidence many scientists are atheists. But so are plenty of non-scientists. This point is simple, and is utterly disconnected from morality. Santa Claus might illustrate some sort of imperfect morality as metaphor (not that I think that this is the case) but that that doesn't mean Santa exists, or that the argument for Santa depends in some way on whether or not the Tooth Fairy is needed to fill in moral gaps in pure Santaism.

Many atheists, like many theists, have an admirable personal moral system. Indeed, since they act in morally good way without any hope or expectation of postmortem supernatural reward or punishment, one could argue that a good atheist is a much better person than a good theist whose good acts are in any part motivated by hope of reward or to avoid punishment. Atheists tend to recognize that if heaven or hell exist, they exist right here, right now, on Earth and human action is the only thing that can increase the prevalence of the one and decrease the prevalence of the other. An observation that was reportedly made several thousand years ago by the non-supernatural empirical social philosopher atheist, Siddhartha, a.k.a. Buddha.

Atheists often try to live a life that minimizes both their suffering and the suffering of those around them, and to work for a better world for all because that's the only safe and secure way to maximize a better world for themselves and those they care about. A rational morality is actually quite possible without an imaginary source of supposedly perfect magical justice in a world that is quite obviously lacking any such thing.

rgb

Hmmm, sounds like a commercial opportunity there. The LEG processor? It could be a hit!

rgb

Not the typical way one might think pigs would fly?

Whew! Thank goodness. I was starting to worry about Al Queda style pig terrorists crashing massive jets into Smithfield.

rgb

I dialed this number, but the beast put me on hold listening to muzak.

So you're saying that we should instead be trying to re-introduce something a bit more innocuous, like smallpox or giant locusts or Dire Wolves?

Makes sense to me. But I mostly like the idea (following) of re-introducing the Carolina Parakeet. Or Wooly Mammoths. I bet they'd love Alaska, and it would give certain people something new to hunt to distract them from the pursuit of dangerous activities, like running for president. Besides, why should Africa and Asia have all of the really dangerous large mammals? We have nothing larger than a coyote to worry about in Durham, and the only human-relevant animals at risk from them are small yappy dogs and the occasional fat baby. Now a Dire Wolf -- that would be really cool. Since there isn't a large enough food supply, they'd almost instantly start predating on humans and livestock. Take that India! Finally, our man-eaters can stand up to yours and America no longer needs to hang its head in shame!

Or, I dunno, do Dire Wolves eat Passenger Pigeons? Do Passenger Pigeons eat Kudzu? Do Snakeheads eat Lionfish? Can Lionfish adapt to freshwater and eat Zebra Mussels? I'm feeling a full resculpting of the US ecology here...

rgb

Ahhh, then all is chaos. Things fall apart; the center cannot hold. Mere anarchy is loosed upon the world.