This is almost only Norway, in the rest of Scandinavia the rules are different:
Norway settled shortly after WW2 on big luxury taxes on cars: Only the very rich can afford them so we can tax them heavily, right? This stayed with us to now, with import duties of up to 180%, and then an additional sales tax of 25%. This means that a high-end fast sports car would cost 3 times as much here as in the US or major parts of the EU.
For EVs however there is neither import duties nor sales tax, which means that a BMW or Audi with similar performance to a low-end Model S (sub 5-sec 0 to 100 km/h times) will cost a lot more than the EV, while a supercar/hypercar which can compete with a P100DL (~2.5 sec) will cost from 2 to 10 times as much.
Denmark had similar EV rules until a year ago, when the tax breaks went away all EV sales effectively stopped. (Denmark is the only country in the world with higher car taxation than Norway.)
Sweden with a big domestic car industry have never had those huge taxes, so there the EV situation is closer to the US, but Tesla and other EVs are still selling quite well.
Anyway, Subaru is a popular brand in Norway so if they can deliver a long-range 4x4 EV they will indeed have many buyers lining up!
You sound a lot like many others who try to come up with marginal use cases as to why they cannot have an EV as their only car.:-)
I.e. our previous 2-3 cars all had a tow bar which I typically used once during the time we owned the vehicle, such a tow bar isn't available for a Tesla Model S, right?
This doesn't turn out to be a real problem as long as we have friends with regular SUVs: Just after buying the Tesla we had several couples over for dinner and then somebody brought up this particular issue - "How will you manage to pull a trailer with gear up to your cabin?"
- That's easy, I'm betting at least one of you guys would be willing to swap your SUV for my Tesla on any given weekend!
I immediately got 4 offers for such a swap.:-)
I.e. we don't need every car to have all capabilities, just that the total sum of use cases at any given time is covered. This is similar to lots of standard queue theory problems, like the old local vs long distance phone exchange capacity calculation.
As others have commented, that depends a lot on the car and the cold weather support:
In Norway all Teslas are ordered with the cold weather package and we start preheating the car from the app 10-30 min before leaving on a winter morning, i.e. while the car is still plugged in. With active cooling and heating of the battery range drops far less than for many older EVs. New slushy snow on the road is a much more serious problem, either that or a really heavy rain can easily increase power usage by 15-25%, but I have never seen more than about 30% additional power use/km.
I.e. we have never had any problems driving 240-250 km over one mountain pass and up to Hardangervidda as long as the car had been plugged in overnight.
As long as you have a regular 240V 16A outdoor plug available within reach of the car you can recharge any model over a normal weekend (friday evening to sunday afternoon): You'll get about 13 km/hour of additional range, so in 40+ hours you can add more than 500 km which is enough to take a Tesla 100 kWh battery from completely empty to 100% full.
Many people do not have any charging available at all, so they typically have to either charge on the last available supercharger, or just have enough range to make it all the way and back again, something which works for most cabins since they tend to be located 100-200 km from where people live.
EVs are simply inevitable, the only ting that have held them back (i.e."only" 29% of all new cars in 2016) here is the fact that most people prefers 4x4 station wagons for carrying stuff up to their winter cabins, and so far only Tesla have been able to provide more or less that, and at a price point which is more or less the same as a Volvo or BMW 4x4.
As soon as you can buy a dual-motor (4x4) EV with reasonable range for under $50K, no more ICE cars will be sold here.
My father was the Chairman of the largest EV importer in Norway for a number of years, so my family had various EVs as second cars, and I got intimately familiar with range anxiety from those. Based on that and the need for 4x4 I believed I had to wait for the Tesla Model X to be able to use an EV as our only car, but when they announced dual-motor versions of Model S I immediately decided to order one.
In hindsight my only regret is that at least some of the extra perks EVs get here have to go away over the next few years, the tax people have to get their revenue some way which means that the toll roads will start charging us, parking won't be free any more and we'll probably lose general access to bus & taxi lanes.
Terje PS. Since Norway is a net exporter of hydro-electric power, all EVs are really 100% pollution free here, in countries with lots of coal-fired power plants in the grid mix the case isn't quite so obvious but still better than the very best ICE cars.
As Kjella writes in another post, this particular area is the single worst weather hurdle along the entire Norwegian coast, and we do have a lot of coastline:
I.e. significantly longer than the US even when you include Alaska, this meant that sea travel was by far the most important transportation network here at least since the vikings.
It is somewhat telling that the coastal route around the country (where the Hurtigruten goes between Bergen and Kirkenes, taking 11 days for the round trip) is considered "highway 1", our road system numbering therefore starts with highway 2.
The english wikipedia article about this project is somewhat short but still pretty good, mentioning that the first proposal came in 1874.
This is a true story, it happened to me 10-15 years ago:
At that time I had a very independent role as the main IT troubleshooter for a large (75K employees in 70+ countries) international company, I ran my own group doing this, but company policy required me to have a manager who would be responsible for signing any travel expense reports and handle my year-end evaluation talk.
I knew going into that interview that I had a _lot_of very happy (internal) customers, with a 98+% solving rate for all the issues my group had gotten, so I was expecting a good review, and things started well:
"Terje, as we both know you don't really work for me so I had to talk to some of your corporate customers and they were very happy indeed! In fact, according to them we should probably put up a bronze statue of you outside the main office building."
(Yes, this means a huge raise right?)
"However, since you don't actually do any work for me directly I have given you a zero rating so that I can use the entire salary allocation for my own people."
At that point I just stood up, said "I don't think we have anything else to discuss" and walked over to the HR department and told them to find me a new manager.
Needless to say it took me a few years to recover the raise I should have gotten that year.:-(
Before EVs, the bus (& taxi) lanes were never clogged here in Oslo, they did in fact have significant spare capacity.
When the regulators wanted to encourage EVs they said up front that we can let them drive in the bus lanes, but only up to a point: As soon as there are enough of them that they actually slow down the buses, then we'll take away that incentive.
This duly happened a year or two ago, for a few highly congested stretches, and now you cannot drive E18 bus lanes during rush hours unless your EV is also a HOV, which in this case means having at least two people in the car.
1. Division is the dual of multiplication, namely it is defined as:
a/b = c
a = b*c
However when a != 0, such as 1, b =0, and using the broken IEEE re-definition of c=Inf, then this implies that 'a' is...
1 = 0*inf... which is utterly stupid as this is impossible. Why is the IEEE754 standards hijacking mathematics to redefine basic concepts???
First, 754 is very emphatically NOT mathematics, it is rather a (imho) very good attempt to make an internally consistent set of rules that allow you to perform real-life calculations with as good a precision as the storage format allows.
The decision to define 1/0 as Inf (and 1/-0 as -Inf) follows directly from this: If the only thing you use such an Inf for is to scale another value (1/0 -> inf, x/inf -> 0), then you will end up with a true zero, which is the closest possible approximation to the real result (i.e. if the zero divisor was the truncated limit of something approaching but not quite becoming a true mathematical zero). If you try to use such an Inf for almost anything else, the result will indeed become a NaN, which is what you wanted anyway, right?
I.e. 754 tries to retain as much potentially useful information as possible.
Like I said there is a neverending split between those who work in polar coordinates and _know_ that there is only a single Inf, and those who use cartesian and absolutely require signed Inf. If you read some of the 754 history out there you will see that this has been a very sore spot all the way back to the original 8087.:-)
BTW. You wouldn't happen to be THE Terje Mathisen of optimization fame by chance?!
Guilty as charged, still trying to optimize code every week, and to teach the mindset needed to younger programmers.:-)
I know that classic quote, "premature optimization is the root of all evil", but I still find it impossible to write any significant code at all before I have figured out an efficient way to solve any given problem.:-(
I hope we all agree that 1/0 should indeed return Inf?
The problem areas are mostly related to single vs dual zeroes and infinities imho, what is your particular problem?
Quoting from the standard:
7.3 Division by zero 7.3.0 The divideByZero exception shall be signaled if and only if an exact infinite result is defined for an operation on finite operands. The default result of divideByZero shall be an (Infinity symbol) correctly signed according to the operation:
For division, when the divisor is zero and the dividend is a finite non-zero number, the sign of the infinity is the exclusive OR of the operands’ signs (see 6.3).
I've read all comments as of this time and nobody seems to have taken note of his suggestion about bottom vars:
"There's an argument among language designers, should we have bottom values at all? But there's nobody who thinks you should have two of them."
I would like to _strongly_ disagree, you _do_ need two different kinds:
undefined (Not a Number/Not a Result) which traps if you try to use it, and none which means empty/ignore!
In the Mill cpu architecture (http://millcomputing.com/) we have those two different kinds and they make coding both easier/more elegant/more compact, and at the same time faster and more secure!
Another example:
I am currently on the group that works on the 2018 revision of the IEEE 754 (i.e. floating point) standard. In the original '754 version the "Not a Number" (NaN) type was defined as a way to create a "sticky" error marker in a numeric calculation. I.e. if you accidentally try to calculate 0/0 or Inf/Inf the result will be undefined, the operation might trap or not depending upon how your language runtime is setup, but the result will always be a NaN. There are two kinds of NaNs, Signaling NaN and Quiet NaN, the only difference is that the next time a SNaN is taken as input to an operation it will trap and then be converted to the equivalent QNaN while a QNaN as input will just propagate to the output.
It should be obvious that if your runtime initializes all FP variables to NaN, then any accidental use-before-load should be detected, right?
The problem is that for the 2008 (current) revision of the standard, enough people wanted a totally different behavior when searching for the maximum value in an array, typically used to scale a matrix: They managed to define minNum(a,NaN)/maxNum(NaN,b) so as to ignore any quiet NaN val ues, always returning the other value. I.e. in those functions they got NaN to behave as None!
The real problem, and the main reason these functions are going away is how the definition above interact with the SNaN/QNaN rules:
So if you look for the maximum of 4 values, one of them a SNaN, the result will depend on the order of comparisons, i.e. if you do them pairwise you get this result:
Norway has had 0.02 as the legal limit for _many_ years now, this basically means that you cannot drive after a single half liter of beer, glass of wine or a shot of whisky.
I.e. all driving after drinking is drunk driving. BTW, when Norway introduced a legal driving limit in 1936, it was the first country in the world to do so:
This web site (in Norwegian) shows the current rules: 0.02 to 0.05% leads to a fine of 1.5 months worth of your gross salary (or average income if you're a stock broker or similar), which means that it can get very expensive indeed when if the driver is a rich idiot. (Those fines are for when you are stopped without any accident, in a crash they will go up and your insurance won't cover anything.)
At 0.12%, i.e. 50% over the US limit, you are looking at at least 21 days in prison on top of that huge fine.
We have a lot more Teslas per capita here than in any other country but I haven't heard of a single drunk driving incident so far.
"Fast cars don't kill people, bad drivers kill people."
We had this exact problem at a former place of employment, i.e. we had contract requirements to provide access to original oil field data for the 25-year lifetime of the field, the problem was that most of this data was in the form of seismic data locked into a specific version of the exploration sw.
The solution we came up with depended on making a virtual machine image of everything needed to run the original application & data, including license files and user databases, and then freeze the system clock: This way we could restart that image at any point in the future and as far as the sw would know it was still 2005.
We would still need regular maintenance, to make sure that newer versions of the virtualization platform could still run the original image. In the worst case we expected to have to add an additional virtualization layer, i.e. so we could run the 2005 sw inside a 2015 virtual machine which would run inside a 2030 VM host.
This approach has of course been used to good effect in order to save classic games.
There's been a lot of research (particularly on mice) which shows that _limited_ starving will increase the life expectancy of the test animals, right?
This looks like one possible factor in the explanation for that effect.
Some of those fjords are 200+ meters deep at the narrowest points near the outlet, i.e. where you would want to build a bridge/tunnel/submerged tube.
We already use tunnel crossings underneath a lot of shallower crossings, and several not so shallow, like the one about half an hour south of Oslo, near Drøbak:
The tunnel is 7-8 km long even though the fjord is less than a km wide at that point, the extra distance was required in order to keep the incline at or below the (highway) maximum allowable 7%. The problem is that 3+ km of 7% downhill (requiring a lot of braking for a heavy rig) and then 3+ km of steep uphill is sufficient to cause trailer breakdowns more or less every week. We also get truck/bus fires inside tunnels almost every year here in Norway.
I am currently in the Hvaler archipelago on the south-east corner of Norway, a few km from the Swedish border. The main/only road leading to the largest of the many islands is nearly 4 km long and still needed 10% descent/ascent angles to get deep enough.
This is dangerous enough to force the entire tunnel to close down whenever a truck with dangerous/inflammable cargo (i.e. gasoline/LPG/diesel) needs to pass through.
I have worked previously in the US but I must say that I prefer the Scandinavian setup we have here (in Oslo, Norway):
You must give notice, typically 3 months from the end of the current month, and if your employer wants to fire you they must also give similar notice, i.e. 3+ months.
For older/more senior employees the notice interval increases for the employer, up to 6+ months for a worker in her sixties.
What this means is that both parties know that they have to stay civilized.
In a case of possible conflict of interest it is common for these long notice intervals to be negotiated down, sometimes to zero. I.e. when I considered leaving my then job to go work for a major client of ours, my CEO told me that I would be allowed to leave immediately. (I didn't accept that offer so the question became moot.)
OTOH, I have been in a situation where I effectively quit immediately, but that was only an in-house transfer:
I went to my yearly performance review after a year of effectively being my own boss, but I still needed someone to be responsible for signing my time sheets and travel expenses etc, so the same person was doing my review.
The guy started the review by saying "Terje, as we both know you aren't really working for me so I had to go out and ask a few of the people you have been helping over the last year, and according to them it sounded like we should put a statue of you outside the corporate headquarters!"
OK, so at this point I was thinking 'This is going very well!' but then he continued "- but since I have a limited sum to distribute for pay raises I have reserved that for my own people and given you a negative evaluation so you will not be getting anything this year".
At this point I stood up, saying "I don't think we have anything else to talk about", left the room and went directly to HR telling them they had better find me a new boss to report to.
Personally I had written algorithms and used them on paper for several years when I started university in 1977 (an MSEE program) and got a compulsory PROGRAMMING 101 class. By the time week two or three came around and we got the second programming assignment I had a wonderful lightbulb moment: "Yes! I can do this! I can calculate anything now"
In 1982 I got a couple of IBM compatible PCs and had to start writing asm code almost at once, because there were no hardware drivers at all, but the result was that I understood everything that happened in those machines, in particular how to make really small & efficient code so that a 4.77 MHz machine with a 4-clock (byte) bus cycle could actually d something useful.
The years since then has been spent filling in all the gaps, i.e. all the stuff that I didn't realize I didn't know.
In the meantime I've been lucky enough to be involved with lots of interesting stuff, like helping to optimize the world's first SW DVD player, the core assembly code for Quake, one of the AES candidates, Intel's reference h.264/CABAC decoder and many more. I've also been part of the NTP Hackers team for 15-20 years now, and I'm also writing FP emulation code for the Mill cpu (millcomputing.com, a cpu with a belt instead of registers).
Conclusion?
I've learned to program by being intensely interested in it for almost 40 years now.
Anyone who became a "programmer" simply because it seemed like an easy way to make a living is more likely to be a part of the problem instead of a part of the solution.
I went from Norway to Utah in 1991, there I met John Cash who used to spend a night every week or two playing Doom deathmatch.
When he fired up his network sniffer he discovered that all LAN communication took place over IPX global broadcast, i.e. they would traverse all routers and end up at every single one of the 6000+ PCs on Novell's internal network!
John found the email of a guy at iD who seemed to know something (John Carmack:-) ) and sent off a message stating basically that the networking code sucked.
A few days later he got a reply: "Sorry about that, we outsourced that development. Here is the source code, please fix it!"
This was "put up or shut up" time, so Jiohn rewrote that code over the next couple of days and returned it.
A couple of years later Cash was hired by Carmack and Abrash as the third core programmer on the Quake team.
Terje PS. I personally sucked at Doom, but since I was involved with Quake asm development from the beginning I became significantly better at that series.
That's the key question: Unless you have an available open access frequency band, this standard is just wishful thinking instead of a new product.
The current allocations in Europe (http://www.erodocdb.dk/docs/doc98/official/pdf/ERCRep025.pdf) covers all of 890-942, 942-960 and 960-1164 MHz, with usage mostly cell phone, radio-navigation and broadcasting.
The absolute minimum latency of that code is 8 clock cycles, assuming that the two initial loads happen at the same time and that the writeback of s1 to state1 is overlapped with the return, i.e. free.
It seems like an obvious optimization to notice that s0 could be updated in parallel with the two initial s1 updates, i.e.
s1 ^= s0;
s1 ^= s0 >> 26;
can instead be written as
s0 ^= s0 >> 26;// These two clock cycles can be overlapped with the previous s1 updates!
s1 ^= s0;
since we don't care about the s0 value after this point and XOR operations are commutative (it is of course possible that the compiler is smart enough to do the same optimization, but I doubt it):
This is two clock cycles faster than the original code.
My father spent months at his home-made light table back around 1965 cutting traces in rubylith film in order to create the offset masks for orienteering maps.
He needed one such mask for each color in the finished map, any mistakes had to be fixed with small amounts of red lacquer which then had to dry completely before it could be recut.
The big advantage for VLSI vs a map was that most lines were straight so you didn't need to trace curved lines like you do for the contours on a map.
The basic output (usually once per second for most GPS chipsets) consists of 7 parameters:
X,Y,Z and dX,dY,dZ along with T, wth the x,y,z values in an Earth Centered Earth Fixed coordinate system. I.e. velocity is an intrinsic output of the processing, resulting from the need to determine doppler values for all visible sats in order to track them.
Past this point many GPS units will do lots of post-processing, for some of them this includes using a lowpass filtered velocity model that uses position deltas instead of or in addition to the raw velocity outputs.
I have run over 500 orienteering races with various GPS units (mostly Garmin watches), and it is indeed true that tracking under a canopy (particularly when it is wet) can be a big challenge, but since the SirfSTAR chipset took over from Garmin's old 12-channel receiver, it is now perfectly usable.
Regarding the original article: Distance measurements depend a lot on how the GPS filters individual measurements!
If you are running along a standard road, then your actual path will be pretty much identical to a set of straight lines, simply because the usual curves on a road are so wide that you get many GPS updates along them. The same goes for XC skiing where a GPS can easily overestimate the distance by introducing spurious sideways noise.
My wife's iPhone consistently overestimate the length of the XC ski tracks in Rauland, Telemark (Norway) due to this: Since I have mapped this entire area I can measure the exact lengths directly from the aerial photos and they corresponds much better with my Garmin 620 and 410 watches. My Garmin Montana which has a much better antenna will normally provide significantly better tracking.
I had both the school issued smallish slide rule and one I had inherited from my father which was much nicer.
However, I used log tables when I wanted even more accurate answers: One year my main wish on my Christmas list was a book that provided full 5-digit log tables.:-)
After I read about Taylor series I realized that I could calculate anything to any accuracy I wanted, but it still took a couple of hours (high school physics class) to calculate pi by hand with 20+ digits using the arctan formula.
(At this point in time, ~1975, I had just bought my first calculator, a TI SR50A which still works when I connect it to a couple of AA batteries instead of the original NiCd rechargable.)
The book consists of three stories, one of them is about a "Hole in the Hole", a Brooklyn junkyard which uses a spacetime rift connecting the junkyard to the Moon in order to get rid of old tires. Our protagonists tries to use said rift to retrieve one of the three Apollo Moon buggies that were left behind.
Having lived in the US previously, I much prefer the Norwegian (and most of the EU) model where you go online or to a dealer and figure out exactly which car you want:
Engine, paint, transmission, seats etc, then you haggle a bit about the price and order it, with delivery a number of weeks later.
In the US it seemed dealers really needed to be able to deliver a car TODAY, not tomorrow or next week.
Personally I ordered a Tesla 4WD model a few days ago, for delivery in the beginning of March.
The main difference from my last car was in the fixed sticker price: No haggling about rebates, just a simple take it or leave it offer.
The main reason for getting a Tesla here in Norway is of course our incredibly high import duties and taxes on regular cars (a car with a V8 engine would probably cost 2.5 to 3 times as much as in the US), while a Tesla has no import duties, no sales tax, no road fees and lots of free parking & charging. In a couple of years they have stated that the relative subsidies for zero emission vehicles will get a cap, so only smaller cars will be able to take full advantage.
Slashdot Mirror
This is almost only Norway, in the rest of Scandinavia the rules are different:
Norway settled shortly after WW2 on big luxury taxes on cars: Only the very rich can afford them so we can tax them heavily, right? This stayed with us to now, with import duties of up to 180%, and then an additional sales tax of 25%. This means that a high-end fast sports car would cost 3 times as much here as in the US or major parts of the EU.
For EVs however there is neither import duties nor sales tax, which means that a BMW or Audi with similar performance to a low-end Model S (sub 5-sec 0 to 100 km/h times) will cost a lot more than the EV, while a supercar/hypercar which can compete with a P100DL (~2.5 sec) will cost from 2 to 10 times as much.
Denmark had similar EV rules until a year ago, when the tax breaks went away all EV sales effectively stopped. (Denmark is the only country in the world with higher car taxation than Norway.)
Sweden with a big domestic car industry have never had those huge taxes, so there the EV situation is closer to the US, but Tesla and other EVs are still selling quite well.
Anyway, Subaru is a popular brand in Norway so if they can deliver a long-range 4x4 EV they will indeed have many buyers lining up!
Terje
You sound a lot like many others who try to come up with marginal use cases as to why they cannot have an EV as their only car. :-)
I.e. our previous 2-3 cars all had a tow bar which I typically used once during the time we owned the vehicle, such a tow bar isn't available for a Tesla Model S, right?
This doesn't turn out to be a real problem as long as we have friends with regular SUVs: Just after buying the Tesla we had several couples over for dinner and then somebody brought up this particular issue - "How will you manage to pull a trailer with gear up to your cabin?"
- That's easy, I'm betting at least one of you guys would be willing to swap your SUV for my Tesla on any given weekend!
I immediately got 4 offers for such a swap. :-)
I.e. we don't need every car to have all capabilities, just that the total sum of use cases at any given time is covered. This is similar to lots of standard queue theory problems, like the old local vs long distance phone exchange capacity calculation.
Terje
As others have commented, that depends a lot on the car and the cold weather support:
In Norway all Teslas are ordered with the cold weather package and we start preheating the car from the app 10-30 min before leaving on a winter morning, i.e. while the car is still plugged in. With active cooling and heating of the battery range drops far less than for many older EVs. New slushy snow on the road is a much more serious problem, either that or a really heavy rain can easily increase power usage by 15-25%, but I have never seen more than about 30% additional power use/km.
I.e. we have never had any problems driving 240-250 km over one mountain pass and up to Hardangervidda as long as the car had been plugged in overnight.
Terje
As long as you have a regular 240V 16A outdoor plug available within reach of the car you can recharge any model over a normal weekend (friday evening to sunday afternoon): You'll get about 13 km/hour of additional range, so in 40+ hours you can add more than 500 km which is enough to take a Tesla 100 kWh battery from completely empty to 100% full.
Many people do not have any charging available at all, so they typically have to either charge on the last available supercharger, or just have enough range to make it all the way and back again, something which works for most cabins since they tend to be located 100-200 km from where people live.
Terje
EVs are simply inevitable, the only ting that have held them back (i.e."only" 29% of all new cars in 2016) here is the fact that most people prefers 4x4 station wagons for carrying stuff up to their winter cabins, and so far only Tesla have been able to provide more or less that, and at a price point which is more or less the same as a Volvo or BMW 4x4.
As soon as you can buy a dual-motor (4x4) EV with reasonable range for under $50K, no more ICE cars will be sold here.
My father was the Chairman of the largest EV importer in Norway for a number of years, so my family had various EVs as second cars, and I got intimately familiar with range anxiety from those. Based on that and the need for 4x4 I believed I had to wait for the Tesla Model X to be able to use an EV as our only car, but when they announced dual-motor versions of Model S I immediately decided to order one.
In hindsight my only regret is that at least some of the extra perks EVs get here have to go away over the next few years, the tax people have to get their revenue some way which means that the toll roads will start charging us, parking won't be free any more and we'll probably lose general access to bus & taxi lanes.
Terje
PS. Since Norway is a net exporter of hydro-electric power, all EVs are really 100% pollution free here, in countries with lots of coal-fired power plants in the grid mix the case isn't quite so obvious but still better than the very best ICE cars.
As Kjella writes in another post, this particular area is the single worst weather hurdle along the entire Norwegian coast, and we do have a lot of coastline:
https://en.wikipedia.org/wiki/...
I.e. significantly longer than the US even when you include Alaska, this meant that sea travel was by far the most important transportation network here at least since the vikings.
It is somewhat telling that the coastal route around the country (where the Hurtigruten goes between Bergen and Kirkenes, taking 11 days for the round trip) is considered "highway 1", our road system numbering therefore starts with highway 2.
The english wikipedia article about this project is somewhat short but still pretty good, mentioning that the first proposal came in 1874.
https://en.wikipedia.org/wiki/...
Terje
This is a true story, it happened to me 10-15 years ago:
At that time I had a very independent role as the main IT troubleshooter for a large (75K employees in 70+ countries) international company, I ran my own group doing this, but company policy required me to have a manager who would be responsible for signing any travel expense reports and handle my year-end evaluation talk.
I knew going into that interview that I had a _lot_of very happy (internal) customers, with a 98+% solving rate for all the issues my group had gotten, so I was expecting a good review, and things started well:
"Terje, as we both know you don't really work for me so I had to talk to some of your corporate customers and they were very happy indeed! In fact, according to them we should probably put up a bronze statue of you outside the main office building."
(Yes, this means a huge raise right?)
"However, since you don't actually do any work for me directly I have given you a zero rating so that I can use the entire salary allocation for my own people."
At that point I just stood up, said "I don't think we have anything else to discuss" and walked over to the HR department and told them to find me a new manager.
Needless to say it took me a few years to recover the raise I should have gotten that year. :-(
Terje
Before EVs, the bus (& taxi) lanes were never clogged here in Oslo, they did in fact have significant spare capacity.
When the regulators wanted to encourage EVs they said up front that we can let them drive in the bus lanes, but only up to a point: As soon as there are enough of them that they actually slow down the buses, then we'll take away that incentive.
This duly happened a year or two ago, for a few highly congested stretches, and now you cannot drive E18 bus lanes during rush hours unless your EV is also a HOV, which in this case means having at least two people in the car.
Terje
1. Division is the dual of multiplication, namely it is defined as:
a/b = c
a = b*c
However when a != 0, such as 1, b =0, and using the broken IEEE re-definition of c=Inf, then this implies that 'a' is ...
1 = 0*inf ... which is utterly stupid as this is impossible. Why is the IEEE754 standards hijacking mathematics to redefine basic concepts???
First, 754 is very emphatically NOT mathematics, it is rather a (imho) very good attempt to make an internally consistent set of rules that allow you to perform real-life calculations with as good a precision as the storage format allows.
The decision to define 1/0 as Inf (and 1/-0 as -Inf) follows directly from this: If the only thing you use such an Inf for is to scale another value (1/0 -> inf, x/inf -> 0), then you will end up with a true zero, which is the closest possible approximation to the real result (i.e. if the zero divisor was the truncated limit of something approaching but not quite becoming a true mathematical zero). If you try to use such an Inf for almost anything else, the result will indeed become a NaN, which is what you wanted anyway, right?
I.e. 754 tries to retain as much potentially useful information as possible.
Like I said there is a neverending split between those who work in polar coordinates and _know_ that there is only a single Inf, and those who use cartesian and absolutely require signed Inf. If you read some of the 754 history out there you will see that this has been a very sore spot all the way back to the original 8087. :-)
BTW. You wouldn't happen to be THE Terje Mathisen of optimization fame by chance?!
Guilty as charged, still trying to optimize code every week, and to teach the mindset needed to younger programmers. :-)
I know that classic quote, "premature optimization is the root of all evil", but I still find it impossible to write any significant code at all before I have figured out an efficient way to solve any given problem. :-(
Terje
I hope we all agree that 1/0 should indeed return Inf?
The problem areas are mostly related to single vs dual zeroes and infinities imho, what is your particular problem?
Quoting from the standard:
7.3 Division by zero 7.3.0 The divideByZero exception shall be signaled if and only if an exact infinite result is defined for an
operation on finite operands. The default result of divideByZero shall be an (Infinity symbol) correctly signed according to
the operation:
For division, when the divisor is zero and the dividend is a finite non-zero number, the sign of the
infinity is the exclusive OR of the operands’ signs (see 6.3).
Terje
I've read all comments as of this time and nobody seems to have taken note of his suggestion about bottom vars:
"There's an argument among language designers, should we have bottom values at all? But there's nobody who thinks you should have two of them."
I would like to _strongly_ disagree, you _do_ need two different kinds:
undefined (Not a Number/Not a Result) which traps if you try to use it, and none which means empty/ignore!
In the Mill cpu architecture (http://millcomputing.com/) we have those two different kinds and they make coding both easier/more elegant/more compact, and at the same time faster and more secure!
Another example:
I am currently on the group that works on the 2018 revision of the IEEE 754 (i.e. floating point) standard. In the original '754 version the "Not a Number" (NaN) type was defined as a way to create a "sticky" error marker in a numeric calculation. I.e. if you accidentally try to calculate 0/0 or Inf/Inf the result will be undefined, the operation might trap or not depending upon how your language runtime is setup, but the result will always be a NaN. There are two kinds of NaNs, Signaling NaN and Quiet NaN, the only difference is that the next time a SNaN is taken as input to an operation it will trap and then be converted to the equivalent QNaN while a QNaN as input will just propagate to the output.
It should be obvious that if your runtime initializes all FP variables to NaN, then any accidental use-before-load should be detected, right?
The problem is that for the 2008 (current) revision of the standard, enough people wanted a totally different behavior when searching for the maximum value in an array, typically used to scale a matrix: They managed to define minNum(a,NaN)/maxNum(NaN,b) so as to ignore any quiet NaN val
ues, always returning the other value. I.e. in those functions they got NaN to behave as None!
The real problem, and the main reason these functions are going away is how the definition above interact with the SNaN/QNaN rules:
maxNum(1.0, QNaN) -> 1.0
maxNum(QNaN, 1.0) -> 1.0
maxNum(1.0, SNaN) -> QNaN
maxNum(SNaN, 1.0) -> QNaN
So if you look for the maximum of 4 values, one of them a SNaN, the result will depend on the order of comparisons, i.e. if you do them pairwise you get this result:
max(1.0, SNaN, 2.0, 3.0) -> maxNum(maxNum(1.0, SNaN), maxNum(2.0, 3.0)) -> maxNum(QNaN, 3.0) -> 3.0
while taking alternate inputs results in
maxNum(maxNum(1.0, 2.0), maxNum(SNaN, 3.0)) -> maxNum(2.0, QNaN) -> 2.0
I.e. we would have been much better off here with a single bit pattern meaning None which would never propagate.
Norway has had 0.02 as the legal limit for _many_ years now, this basically means that you cannot drive after a single half liter of beer, glass of wine or a shot of whisky.
I.e. all driving after drinking is drunk driving. BTW, when Norway introduced a legal driving limit in 1936, it was the first country in the world to do so:
http://www.promille.no/promill...
This web site (in Norwegian) shows the current rules: 0.02 to 0.05% leads to a fine of 1.5 months worth of your gross salary (or average income if you're a stock broker or similar), which means that it can get very expensive indeed when if the driver is a rich idiot. (Those fines are for when you are stopped without any accident, in a crash they will go up and your insurance won't cover anything.)
At 0.12%, i.e. 50% over the US limit, you are looking at at least 21 days in prison on top of that huge fine.
We have a lot more Teslas per capita here than in any other country but I haven't heard of a single drunk driving incident so far.
"Fast cars don't kill people, bad drivers kill people."
We had this exact problem at a former place of employment, i.e. we had contract requirements to provide access to original oil field data for the 25-year lifetime of the field, the problem was that most of this data was in the form of seismic data locked into a specific version of the exploration sw.
The solution we came up with depended on making a virtual machine image of everything needed to run the original application & data, including license files and user databases, and then freeze the system clock: This way we could restart that image at any point in the future and as far as the sw would know it was still 2005.
We would still need regular maintenance, to make sure that newer versions of the virtualization platform could still run the original image. In the worst case we expected to have to add an additional virtualization layer, i.e. so we could run the 2005 sw inside a 2015 virtual machine which would run inside a 2030 VM host.
This approach has of course been used to good effect in order to save classic games.
Terje
There's been a lot of research (particularly on mice) which shows that _limited_ starving will increase the life expectancy of the test animals, right?
This looks like one possible factor in the explanation for that effect.
Terje
Easy answer:
Some of those fjords are 200+ meters deep at the narrowest points near the outlet, i.e. where you would want to build a bridge/tunnel/submerged tube.
We already use tunnel crossings underneath a lot of shallower crossings, and several not so shallow, like the one about half an hour south of Oslo, near Drøbak:
The tunnel is 7-8 km long even though the fjord is less than a km wide at that point, the extra distance was required in order to keep the incline at or below the (highway) maximum allowable 7%. The problem is that 3+ km of 7% downhill (requiring a lot of braking for a heavy rig) and then 3+ km of steep uphill is sufficient to cause trailer breakdowns more or less every week. We also get truck/bus fires inside tunnels almost every year here in Norway.
I am currently in the Hvaler archipelago on the south-east corner of Norway, a few km from the Swedish border. The main/only road leading to the largest of the many islands is nearly 4 km long and still needed 10% descent/ascent angles to get deep enough.
This is dangerous enough to force the entire tunnel to close down whenever a truck with dangerous/inflammable cargo (i.e. gasoline/LPG/diesel) needs to pass through.
I have worked previously in the US but I must say that I prefer the Scandinavian setup we have here (in Oslo, Norway):
You must give notice, typically 3 months from the end of the current month, and if your employer wants to fire you they must also give similar notice, i.e. 3+ months.
For older/more senior employees the notice interval increases for the employer, up to 6+ months for a worker in her sixties.
What this means is that both parties know that they have to stay civilized.
In a case of possible conflict of interest it is common for these long notice intervals to be negotiated down, sometimes to zero. I.e. when I considered leaving my then job to go work for a major client of ours, my CEO told me that I would be allowed to leave immediately. (I didn't accept that offer so the question became moot.)
OTOH, I have been in a situation where I effectively quit immediately, but that was only an in-house transfer:
I went to my yearly performance review after a year of effectively being my own boss, but I still needed someone to be responsible for signing my time sheets and travel expenses etc, so the same person was doing my review.
The guy started the review by saying "Terje, as we both know you aren't really working for me so I had to go out and ask a few of the people you have been helping over the last year, and according to them it sounded like we should put a statue of you outside the corporate headquarters!"
OK, so at this point I was thinking 'This is going very well!' but then he continued "- but since I have a limited sum to distribute for pay raises I have reserved that for my own people and given you a negative evaluation so you will not be getting anything this year".
At this point I stood up, saying "I don't think we have anything else to talk about", left the room and went directly to HR telling them they had better find me a new boss to report to.
Terje
That was indeed the usual way:
Personally I had written algorithms and used them on paper for several years when I started university in 1977 (an MSEE program) and got a compulsory PROGRAMMING 101 class. By the time week two or three came around and we got the second programming assignment I had a wonderful lightbulb moment: "Yes! I can do this! I can calculate anything now"
In 1982 I got a couple of IBM compatible PCs and had to start writing asm code almost at once, because there were no hardware drivers at all, but the result was that I understood everything that happened in those machines, in particular how to make really small & efficient code so that a 4.77 MHz machine with a 4-clock (byte) bus cycle could actually d something useful.
The years since then has been spent filling in all the gaps, i.e. all the stuff that I didn't realize I didn't know.
In the meantime I've been lucky enough to be involved with lots of interesting stuff, like helping to optimize the world's first SW DVD player, the core assembly code for Quake, one of the AES candidates, Intel's reference h.264/CABAC decoder and many more. I've also been part of the NTP Hackers team for 15-20 years now, and I'm also writing FP emulation code for the Mill cpu (millcomputing.com, a cpu with a belt instead of registers).
Conclusion?
I've learned to program by being intensely interested in it for almost 40 years now.
Anyone who became a "programmer" simply because it seemed like an easy way to make a living is more likely to be a part of the problem instead of a part of the solution.
Terje
I went from Norway to Utah in 1991, there I met John Cash who used to spend a night every week or two playing Doom deathmatch.
When he fired up his network sniffer he discovered that all LAN communication took place over IPX global broadcast, i.e. they would traverse all routers and end up at every single one of the 6000+ PCs on Novell's internal network!
John found the email of a guy at iD who seemed to know something (John Carmack :-) ) and sent off a message stating basically that the networking code sucked.
A few days later he got a reply: "Sorry about that, we outsourced that development. Here is the source code, please fix it!"
This was "put up or shut up" time, so Jiohn rewrote that code over the next couple of days and returned it.
A couple of years later Cash was hired by Carmack and Abrash as the third core programmer on the Quake team.
Terje
PS. I personally sucked at Doom, but since I was involved with Quake asm development from the beginning I became significantly better at that series.
That's the key question: Unless you have an available open access frequency band, this standard is just wishful thinking instead of a new product.
The current allocations in Europe (http://www.erodocdb.dk/docs/doc98/official/pdf/ERCRep025.pdf) covers all of 890-942, 942-960 and 960-1164 MHz, with usage mostly cell phone, radio-navigation and broadcasting.
Terje
The new 128-bit generator is shown as this piece of code, using a pair of 64-bit state variables:
uint64_t state0 = 1;
uint64_t state1 = 2;
uint64_t xorshift128plus() {
uint64_t s1 = state0;
uint64_t s0 = state1;
state0 = s0;
s1 ^= s1 > 17;
s1 ^= s0;
s1 ^= s0 >> 26;
state1 = s1;
}
The absolute minimum latency of that code is 8 clock cycles, assuming that the two initial loads happen at the same time and that the writeback of s1 to state1 is overlapped with the return, i.e. free.
It seems like an obvious optimization to notice that s0 could be updated in parallel with the two initial s1 updates, i.e.
s1 ^= s0;
s1 ^= s0 >> 26;
can instead be written as
s0 ^= s0 >> 26; // These two clock cycles can be overlapped with the previous s1 updates!
s1 ^= s0;
since we don't care about the s0 value after this point and XOR operations are commutative (it is of course possible that the compiler is smart enough to do the same optimization, but I doubt it):
This is two clock cycles faster than the original code.
Terje
My father spent months at his home-made light table back around 1965 cutting traces in rubylith film in order to create the offset masks for orienteering maps.
He needed one such mask for each color in the finished map, any mistakes had to be fixed with small amounts of red lacquer which then had to dry completely before it could be recut.
The big advantage for VLSI vs a map was that most lines were straight so you didn't need to trace curved lines like you do for the contours on a map.
Terje
Sorry, that's simply wrong:
The basic output (usually once per second for most GPS chipsets) consists of 7 parameters:
X,Y,Z and dX,dY,dZ along with T, wth the x,y,z values in an Earth Centered Earth Fixed coordinate system. I.e. velocity is an intrinsic output of the processing, resulting from the need to determine doppler values for all visible sats in order to track them.
Past this point many GPS units will do lots of post-processing, for some of them this includes using a lowpass filtered velocity model that uses position deltas instead of or in addition to the raw velocity outputs.
I have run over 500 orienteering races with various GPS units (mostly Garmin watches), and it is indeed true that tracking under a canopy (particularly when it is wet) can be a big challenge, but since the SirfSTAR chipset took over from Garmin's old 12-channel receiver, it is now perfectly usable.
http://tmsw.no/qr/index.php?us...
Regarding the original article: Distance measurements depend a lot on how the GPS filters individual measurements!
If you are running along a standard road, then your actual path will be pretty much identical to a set of straight lines, simply because the usual curves on a road are so wide that you get many GPS updates along them. The same goes for XC skiing where a GPS can easily overestimate the distance by introducing spurious sideways noise.
My wife's iPhone consistently overestimate the length of the XC ski tracks in Rauland, Telemark (Norway) due to this: Since I have mapped this entire area I can measure the exact lengths directly from the aerial photos and they corresponds much better with my Garmin 620 and 410 watches. My Garmin Montana which has a much better antenna will normally provide significantly better tracking.
Terje
I had both the school issued smallish slide rule and one I had inherited from my father which was much nicer.
However, I used log tables when I wanted even more accurate answers: One year my main wish on my Christmas list was a book that provided full 5-digit log tables. :-)
After I read about Taylor series I realized that I could calculate anything to any accuracy I wanted, but it still took a couple of hours (high school physics class) to calculate pi by hand with 20+ digits using the arctan formula.
(At this point in time, ~1975, I had just bought my first calculator, a TI SR50A which still works when I connect it to a couple of AA batteries instead of the original NiCd rechargable.)
Terje
Last night I bought a Baen EBook: Terry Bisson - Numbers Don't Lie.
The book consists of three stories, one of them is about a "Hole in the Hole", a Brooklyn junkyard which uses a spacetime rift connecting the junkyard to the Moon in order to get rid of old tires. Our protagonists tries to use said rift to retrieve one of the three Apollo Moon buggies that were left behind.
Terje
Having lived in the US previously, I much prefer the Norwegian (and most of the EU) model where you go online or to a dealer and figure out exactly which car you want:
Engine, paint, transmission, seats etc, then you haggle a bit about the price and order it, with delivery a number of weeks later.
In the US it seemed dealers really needed to be able to deliver a car TODAY, not tomorrow or next week.
Personally I ordered a Tesla 4WD model a few days ago, for delivery in the beginning of March.
The main difference from my last car was in the fixed sticker price: No haggling about rebates, just a simple take it or leave it offer.
The main reason for getting a Tesla here in Norway is of course our incredibly high import duties and taxes on regular cars (a car with a V8 engine would probably cost 2.5 to 3 times as much as in the US), while a Tesla has no import duties, no sales tax, no road fees and lots of free parking & charging. In a couple of years they have stated that the relative subsidies for zero emission vehicles will get a cap, so only smaller cars will be able to take full advantage.
Terje