rbanffy is actually correct, the value given is as accurate as you can get for that situation (which will be a 64 bit floating point number). The accuracy starts to get lost at about the seventeenth decimal place and the closest you can actually get to pi in the IEEE standard which has a 52 bit mantissa is:
3.141592653589793115997963468544185162
But sometimes it does matter, especially as those errors will propogate through your calculations and accumulate (especially after a few million iterations). As your math teacher should have told you: Use as much precision as you can throughout your calculation and only drop the insignificant digits at the end.
The best and easiest way to get a value for pi is to use one of the trigonometric functions. When I started programming in fortran I was told to do this:
pi=4.0d0*atan(1.0d0)
which will automatically give you machine precision (depending on the accuracy of the math library).
Also if authentication was widely adopted as a spam filter then your email password would become valuable to spammers which doesn't give me a warm fuzzy feeling.
Once someone's username/password is hacked or intercepted by a spammer then it's almost guaranteed that their spam will then get through. It's not trivial to fix the breach and if the spammers steal enough passwords then the system will collapse.
I thought I read about this somewhere, or maybe it just came up in conversation, but I can't find the reference... Try typing "hard drive eathquake" into the slashdot search engine;) http://science.slashdot.org/article.pl?sid=06/09/0 7/1922214
But you can shift the GM analogy a bit and argue that the equivalent to the petrol that you put in your car is the electricity that comes out of the wall and the quality of that supply can be equally unpredictable.
They will always be able to come up with a technical argument for why you should use their spare parts or consumables. This will be hard to overcome with regulation/legislation as long as they don't get too greedy with their pricing model so they avoid litigation and customers don't think about TCO.
The only reason I can see them changing is if enough of their customers complain about it that it becomes a worthwhile feature to include.
Perhaps people like Dell and Nintendo are using their own proprietary plugs so that people don't buy a cheapo universal charger which is shoddily designed and blows up their equipment.
They would argue that it's a matter of quality control
It used to be around 2,850 Ml/d and I doubt it has changed drastically
So roughly a quarter of the water disappears before it reaches the taps. The reason so much is lost is because the system is getting on for a hundred years old and is falling to bits.
Whilst there was the ability to increase the supply to counteract the losses then the cheapest thing to do in the short term was pump more water down the pipes and spend the repair budget on the biggest leaks. Now the demand is outstripping the supply and so the pressure is on to try and fix the leaks.
When it was privatised then the companies knew they were sitting on a time bomb and so wouldn't take on the risk if there were strict penalties for leaks in the contracts.
Slashdot Mirror
"I'm Spartacus!"
An addendum to my post:
rbanffy is actually correct, the value given is as accurate as you can get for that situation (which will be a 64 bit floating point number). The accuracy starts to get lost at about the seventeenth decimal place and the closest you can actually get to pi in the IEEE standard which has a 52 bit mantissa is: 3.141592653589793115997963468544185162
But sometimes it does matter, especially as those errors will propogate through your calculations and accumulate (especially after a few million iterations). As your math teacher should have told you: Use as much precision as you can throughout your calculation and only drop the insignificant digits at the end.
The best and easiest way to get a value for pi is to use one of the trigonometric functions. When I started programming in fortran I was told to do this:
pi=4.0d0*atan(1.0d0)
which will automatically give you machine precision (depending on the accuracy of the math library).
Sorry, bad link in my post above http://en.wikipedia.org/wiki/SMTP-AUTH
Also if authentication was widely adopted as a spam filter then your email password would become valuable to spammers which doesn't give me a warm fuzzy feeling.
It doesn't help much.
It requires a chain of trust.
Once someone's username/password is hacked or intercepted by a spammer then it's almost guaranteed that their spam will then get through. It's not trivial to fix the breach and if the spammers steal enough passwords then the system will collapse.
http://science.slashdot.org/article.pl?sid=06/09/
But you can shift the GM analogy a bit and argue that the equivalent to the petrol that you put in your car is the electricity that comes out of the wall and the quality of that supply can be equally unpredictable.
They will always be able to come up with a technical argument for why you should use their spare parts or consumables. This will be hard to overcome with regulation/legislation as long as they don't get too greedy with their pricing model so they avoid litigation and customers don't think about TCO.
The only reason I can see them changing is if enough of their customers complain about it that it becomes a worthwhile feature to include.
Perhaps people like Dell and Nintendo are using their own proprietary plugs so that people don't buy a cheapo universal charger which is shoddily designed and blows up their equipment.
They would argue that it's a matter of quality control
I thought that dioxins were only created during the incineration of rubber and plastic products?
It used to be around 2,850 Ml/d and I doubt it has changed drastically
So roughly a quarter of the water disappears before it reaches the taps. The reason so much is lost is because the system is getting on for a hundred years old and is falling to bits.
Whilst there was the ability to increase the supply to counteract the losses then the cheapest thing to do in the short term was pump more water down the pipes and spend the repair budget on the biggest leaks. Now the demand is outstripping the supply and so the pressure is on to try and fix the leaks.
When it was privatised then the companies knew they were sitting on a time bomb and so wouldn't take on the risk if there were strict penalties for leaks in the contracts.