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What's hard to understand about it? It's just

  x = initial
  for y in collection:
    x = f(y, x)

It's easy but it ain't simple. Because `f` can do arbitrary things to `x` you have to look at it just to know the general shape of the computation. Reduce gives you a lot of the flexibility of imperative programming but with that also a lot of the problems. Sometimes that's the right trade-off but it is good to be aware that it is a trade-off.

You mean "f(x, y)", right? Half of the languages that have reduce/fold use this ordering, another half uses yours.

So in effect, as some other commenter said, it's just the loop with worse syntax.


Walmart used to be (and maybe still is?) known for doing this. They would get companies to produce lower-quality versions of products under the same name as the standard versions available elsewhere. They could sell them for cheaper and consumers were none the wiser - or so the theory went, anyway. Obviously people caught on.

People have caught on and nothing can be done because all ten "brands" are produced on the same machine in Ohio

I've noticed this at Aldi too. Boxes of muesli that look 30% cheaper than at other supermarkets... but when you look closer, the box is 3/4 the size and it's only 3/4 full. I don't regularly shop at Aldi.

Don't you look at the unit price? Price per kg or litre.

In the US that's annoying, sometimes they show price per oz, other times price per lbs.

I don't know the specific items that were called out here but I can tell you, as a flight instructor, that the failure to capture the glideslope was already enough to require a go-around. The late flap settings were too. So was the high airspeed. At no point did they have a stabilized approach. There were multiple unequivocal mandatory go-around conditions before they got to the runway.

Turbofans being slow to spool up is jets 101.

So presumably OP never took jets 101. Neither have I. So what? The condescension remains unjustified and contrary to fruitful interaction. (See also the "lucky 10000" xkcd.)

Does any combustion engine, like the one in your car, have instant throttle response? When you hit the kickdown switch in your car there is still a delay before you start really accelerating. Now imagine a much bigger engine - it's not very difficult to guess one of those would take even longer without being familiar with the inner workings of turbine engines.

> OP never took jets 101. Neither have I. So what?

So you,me and OP will likely miss a lot of nuance when discussing jets - after all, reality has a lot of detail. Stating the existence of blindspots is not condescension, having blindspots does not make one inferior.


Time was, if you didn't understand how to use VORs, you couldn't really fly. We used them as primary en route nav, as well as for approaches, for many decades. As a CFI I think most of the confusion around VORs these days comes down to poor or inadequate training.


> As a CFI I think most of the confusion around VORs these days comes down to poor or inadequate training.

I would say it is partially true. The reason I have trouble with VORs is that the equipment inside the plane is very awkward to use. The fact that the plane is in the center of the VOR display is super confusing as it shows everything in reverse: if the line is on the left it means the plane is on the right. And having to learn Morse Code to validate you tuned in the right frequency. And so on.

I get it that when they invented that we did not have technology, but now we do and nothing is stopping us from using a digital display that can translate VORs/DMEs/NDBs fixes into GPS like routes. And knowing where every VOR is can make the map accurate too. That would make it very easy for a lot of people to use and not have to learn the arcane ways of how people used to fly 50 years ago. I don't need to know that I'm flying TO or FROM the station.


That's fair. I replied to someone else with a similar remark, but essentially doing most of my flying in 70s to 90s prop planes, I imagine the tools I'm most used to are just dated. Your point around training is likely very accurate, I had some great teachers but I also had a few instances of being given inaccurate information and having to teach the teacher so to speak.


I don't fly and I wouldn't call my self someone that plays a lot of flight simulator. But I do enjoy navigation methods and I did learn the basics and practices of VOR navigation. I got an Android app that simulates flying courses, holding patterns etc, but only the navigation part. I would say I learned some intuition to it.


A lot of those planes still exist and have not gotten panel upgrades, so IMO you still should learn how to navigate purely via only visual references and radio navigation. I believe you are still required to know how to use them to pass your private pilot check ride, too, but I may be wrong.


> I believe you are still required to know how to use them to pass your private pilot check ride, too, but I may be wrong.

Thankfully, they are not needed to pass a PPL check-ride.

Creating a track on a 1:500k map and fly it is incredibly complicated when you have to do a ton of other things inside the plane too.


> sustaining human life

Not really. Drone ships are very much a thing these days.


How can a drone ship hold its designated position while it's blocking gps?


By stopping jamming for a few seconds every few hours , and navigating using dead reckoning in between? With just a compass, a log, and a watch I can sail for days and end up within two kilometers of my destination.


Shouldn't it be possible for you to reconstruct the original GPS signal if you can control the jamming pattern?


Eh, I doubt it, GPS signal is so weak, once the EM field in the air has so much power, I think the literal hardware ADC of any receiver would be overwhelmed/clipped with a high power jammer nearby. I mean it's possible that the front end will be literally fried, not just clipping the analog front end. GPS is usually -130dBM, it's absurdly weak.

But in theory you're not wrong.


Beyond what everyone else has said it could also have sonar and keep track of its position relative to the local ocean floor like an optical mouse.


Anchor? ;)


Electro-mechanical gyroscope


Probably just turn off the jammer for 2 seconds


Astral navigation is probably accurate enough


Dead reckoning with a minute or two to get a gps fix with the jammer off once a day.


What's to stop someone spoofing a GPS signal during that fix?


Nothing, and if it were subtle enough it could be effective at making it drift around. Lots of ways to get a rough fix though, and you don’t need very good absolute accuracy offshore, using a compass and log to DR your way around. Even better if you have a wind vane and anemometer. The majority of your drift will be wind driven.


A camera that looks at the stars / sun and a very accurate clock...

Or one of the many methods described in TFA.


accelerometers can do that job. Also it can stop the jamming every once in a while to check.


INS


It's unfortunately misleading shorthand for what actually happens: space becomes timelike. It doesn't become time. All this means is that once you cross the event horizon, you can only ever move toward the center of the black hole, in the same way that outside of a black hole, you can only ever move toward the future. You might not take a direct route to the center, but no matter which way you move, you will be following a track that ends at the center.

The reason this phenomenon has a spooky-sounding name is that it also affects whether two objects can be causally connected. If you can only ever move closer to the center of the black hole, then there are (conceivably) other objects inside the event horizon that you can never have a causal relationship with.

But it doesn't mean that space and time literally switch places.


> If the sky was clear, as the article states, then lack of GPS is not a good enough excuse for a trained pilot to crash into a mountain, unless the cockpit has no windows.

I have thousands of hours as pilot in command and have worked as a professional pilot.

Unlit terrain is invisible at night. The moon was new. They did not see, and could not have seen, the mountains.


The "skill issue" is that they chose to press on instead of returning to base. Yes, the jamming was a factor, but making a decision to fly a visual into field surrounded by mountains at night is a bad call.


I'm sorry, what? Pilot error is absolutely a factor in contemporary accidents. It's the most common one, in fact, because we've rooted out almost all the other risks.


And why did the pilot make the error?


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