Domain: tutorialspoint.com
Stories and comments across the archive that link to tutorialspoint.com.
Comments · 16
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2nd law and disorder
Ahh, another thread where electrical and computer engineers demonstrate that they have never taken serious thermodynamics and fail to understand the second law. Allow me to TLDR all your questions:
1. Yes, it is a thing
2. https://www.tutorialspoint.com...
3. No, you failed to factor in taxes to your cost.
4. Yes, if we discover fusion power, but only then.
Your welcome. -
Re: The Onion
Why are your not web apps using HTTP and HTTPS ports?
Why do you think web browsers are the only things that can speak HTTP or HTTPS? Heck, there might be an entire network application protocol that uses HTTP(s) but isn't a browser.
Most likely they just redirected the HTTP and HTTPS ports.
Did they direct them to somewhere other than the Internet? Golly, that sounds a lot like blocking Internet access......
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How to install Winamp under Linux
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Genetic Algorithms
You get an algorithm to create complex non-traditional 3D rotor shapes, simulate their behavior in wind, and then mutate the design, simulate again, and get a machine learning algorithm to learn what sort of mutations lead to a better performing 3D rotor. In theory, enough iterations -- perhaps millions or more -- should eventually lead to the "ultimate rotor"
You're describing Genetic Algorithms. It's a fairly old technique. It shouldn't be too hard to implement it. The problem here is not FOSS, it's computational power. You need quite a lot of CPU time to run all the simulations and evolve the solution.
Some sort of distributed computing framework like INSERT_PROJECT_NAME@home would work. But then you'd have to convince everyone to use it....
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Re:Great.
You could install a WiMax basestation rural areas and have a line of sight microwave link to the nearest place you can get a wired internet connection, or to the next base station.
https://www.tutorialspoint.com...
At my mother's house she used a wireless isp for awhile. It was crap. We switched to a t-mobile hotspot and a 14GB a month plan. (Note that some phones actually have more, but it tends to be non tethered data.)
I will be surprised if Verizon really offers a better deal. At any rate that (barely) meets her needs and is what around 6Mbps. Satellite is of course a mess latency wise and has other issues.
In the unlikely event you can get clear and direct line of sight, you might also be able to user a laser based network, which may be able to transmit whatever the connection is. One property is probably going to need to be at the top of a large hill and even then towers may be required.
At any rate, last I checked t-mobile had the best, no bs true hotspot plan.
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Re:Great.
You could install a WiMax basestation rural areas and have a line of sight microwave link to the nearest place you can get a wired internet connection, or to the next base station.
https://www.tutorialspoint.com...
A WiMAX tower station can connect directly to the Internet using a high-bandwidth, wired connection (for example, a T3 line). It can also connect to another WiMAX tower using a line-of-sight microwave link.
Problem is of course that you'd need to make sure you had enough subscribers to make it profitable before you did it. On the upside you could spread out quite fast this way - so long as the base stations are either in WiMax or microwave range they can talk to each other. So initially you'd put them at the edges of cities where they can get a wired connection and power. Then you'd add ones which talked to them. Eventually you'd be building them way out in the country. You can actually get ones which run off solar and batteries
http://www.eecs.ucf.edu/~zakhi...
I think you'd fall foul of regulations though. Aka 'people trying to protect their monopoly which lets them sell shitty, overpriced services to a captive audience who have no alternative'.
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Re: Learnification
Something like jFiddle but for bash?
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Re:IPv6 tunneling
-you get a rebuild protocol that tried to fixed many shortcomings of ipv4. you get encryption (ipsec) build in, dropped all the obsolete ICMP packets and now ICMP is useful to control the traffic (so no more drop all ICMP as you will lose features)
-you get million of address and enabled you to get public IPs for all your machines, even internal machines. so NAT is not needed anymore. Firewall is still needed, but your home router will mostly stop being a router+NAT+firewall and be router+firewall
-As no NAT, direct connect and p2p is a lot easier, no need for strange hacks and third party servers to punching holes in the firewall
-dhcp, manual ip assignment and similar are past, with ipv6 the setup for users is just plug and use, even without dhcpv6
-header rebuild make routing a lot simpler, so faster connections and also easier to grow
-you can get mobile IPs, that even on different locations, you still get your own IPsimply check this sites:
https://www.tutorialspoint.com...
http://ipv6.com/articles/gener... -
Re:Real Computers
https://www.tutorialspoint.com...
Sure there are others. -
Re:Much rejoicing...
Ah, the magic wires argument. Sure.
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Re:Surprise? Why?
TL:DR; You need to learn HOW to optimize:
@37:30 -- Mike Acton: Code Clinic 2015: How to Write Code the Compiler Can Actually Optimize
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> If you want speed, assembly is the ONLY option.
Total NONSENSE.
A. You keep implying this word optimization -- it doesn't mean what you think it means!
B. There are four lights, er, types of optimizations:
1. Use a lower level language
2. Micro-optimization or Bit-twidling
3. Algorithm
4. Macro or cache-orientated, aka (Data-Orientated Design)What do these mean?
1. Use a lower level language
With bloated languages and incorrect use of C++, Java, etc., inexperienced programmers naively thing changing to a "lower level" language -- such as C or Assembly -- will help speed up their code. While it is true one has access to more programming paradigms in a low level language, i.e. you can use the carry flag as a return value instead of wasting an entire byte with assembly, this type of optimization only takes you so far before you need to look at alternatives.
2. Micro-optimizations
All good programmers should read (and understand!) these bit twiddling optimizations:
* bit-twiddling hacks
* Hackers DelightWhile compilers can generate "good enough code", sometimes hand-optimized instructions can beat the compiler. e.g. Before compilers optimized division with reciprocal multiplication, a common technique for division was to manually change division into reciprocal multiplication. i.e. `/ 3` -> `* 1/3` which means you would see something like this:
int a = 123 / 3;
would be replaced with:
int b = (123 * 65536 / 3) >> 16;
Thankfully most compilers will perform these integer divisions but you can try this out with an online C compiler:
#include <stdio.h>
int main()
{
int a = 123 / 3;
int b = (123 * 65536 / 3) >> 16;
int c = a == b;
printf( "a: %d =%d= b: %d\n", a, c, b );
return 0;
}These types of micro-optimizations are becoming rarer and rarer as compilers (slowly) get better. However Don't assume. VERIFY your assembly output of the compiler.
Floating-point optimizations still show up. The most famous is probably John Carmack's Quake 3 Inverse Square Root
This PDF provides a very good explanation:
* http://www.lomont.org/Math/Pap...
3. Algorithm
The fastest way to optimize (from the programmer's run-time) is to replace a slower algorithm with a faster one.
i.e.
* If the common case for your data is unsorted, then replacing a dog-slow bubble sort with quick-sort will show gains.
* However, if the common caseis that the is 99% mostly sorted, then changing algorithms may not always help.This is where most people start to optimize. BUT, notice how I said "Common Case". There is a _higher level_ of optimization we can do:
4. Macro or Cache-orientated.
The 0th rule in optimization is:
Know Thy Data
When you optimize you need to optimize for the common case. This means understanding data flow, Memoization, and transforms. You _must_ question ALL assumptions, knowns, and unknowns. What, exactly, are you trying to do? i.e. Printing Primes and Printing
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Re:Surprise? Why?
Only shitty programmers continue to make excuses why they are shitty.
Arrogance is assuming you THINK you already know.> In Java you have no influence in caches etc.
FALSE.
Do you actually understand _anything_ about cache lines???
HOW you access memory determines your maximum throughput.
Proof: Here are two different ways to sum up an array:
1. In the first example we access every 0th, 16th, 32nd, 64th element. Then 1st, 17th, 33rd, etc. Then the 2nd, 18th, 34th, etc. Our stride is 16 elements.
2. In the second example we access every element in a contiguous fashion. Our stride is 1 element.If one "had no influence in caches" like you ignorantly assume the timing would be identical. However one is SLOWER then the other.
Copy and paste into an online Java compiler
public class HelloWorld{
public static void main(String []args){
final int _K = 1024;
final int N = 2048 * _K;
int[] a = new int[N];
int sum;
long start, end, dur;
for( int i = 0; i < N; i++ )
a[i] = i & 0xFF;
start = System.nanoTime();
sum = 0;
for( int j = 0; j < 16; j++ )
for( int i = j; i < N; i += 16 )
{
sum += a[ i ];
}
end = System.nanoTime();
dur = (end - start) / 1000000; // milliseconds.
System.out.format( "Sum: %d, Time: %d\n", sum, dur );
start = System.nanoTime();
sum = 0;
for( int i = 0; i < N; i++ )
sum += a[ i ];
end = System.nanoTime();
dur = (end - start) / 1000000; // milliseconds.
System.out.format( "Sum: %d, Time: %d\n", sum, dur );
}
}> Your "lack of understanding of memory access patterns" has nothing to do with assembly or C++.
If you would actually _watch_ and _learn_ you would recognize this is false.
https://youtu.be/rX0ItVEVjHc?t...> libraries that tried to exploit caching behaviour (1993 or so?). However that has nothing to do with assembly
;)Here's your cookie for missing the point"
Assembly language programmers tend to be more knowledgeable of when and where their code is slow. C++ and Java programmers tend to be more ignorant of high performance because they generally don't have a clue _how_ the compiler is generating the corresponding asm for their code -- and then they wonder why it is slow.
A good programmer learns assembly to better understand how to write simpler, smaller, and faster code.
A shitty programmer makes excuses for why they don't understand assembly. -
Re:Nope... Nailed It
I have seen non-project-managed architecture.
We brought in new programmers, and they threw it out because it was a mess. Due to constant demands from everyone using the software being written (which was in production, and getting incremental rearchitecture), the new architecture kept changing: several parts have been rewritten more than once, a lot are glued together to get around bad architecture decisions, and some stuff is just plain wrong and has odd work-arounds.
We can blame the programmers for the architecture; but the truth is they were told, by functional managers, to produce everything that was asked for as it was asked for. They didn't have the luxury of collecting requirements, producing a requirements document, breaking down the work, and then designing the architecture as part of the early phase of work. They had to make up architecture on-the-fly, and integrate it with architecture they were replacing, and integrate it with new architecture for new requirements which couldn't reasonably be met under the architecture they had started implementing.
Project management avoids exactly this;
Add time to every single task you think you see for doing architecture related stuff. At the end, allocate a large blob of time to figure out the correct architecture rather than the one you built which now resembles a dirty snowball. And begin rebuilding the thing, reusing any errant parts you did in pass one. And because you are agile, be sure to appropriate time for execs who understand agile as they get to change what's necessary on the taste of their coffee that day, whether their secretary gave them a perky Good Morning, or whether their hair will turn sufficiently silver in time for that next promotion.
Instead, you break out the work, use that to determine what needs to be done, and have a separate piece of work for product design before implementation.
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prior art exists
based on a very quick search, you can tell them to go fuck themselves. here's the patent:
http://www.google.com/patents/US5506866?printsec=abstract#v=onepage&q&f=falseit's originally by AT&T. it's a patent on the means to combine simultaneous voice and data onto a single line. the submission date is in 1993.
however, if you look at this: http://www.tutorialspoint.com/gsm/gsm_overview.htm
you will see that GSM was started as far back as 1982. GSM includes GPRS, which includes a means to combine simultaneous voice and data into a single transmission.
there will be plenty more examples like this. i recommend that you find lots of examples, but any one of those examples can be used to tell these patent trolls to go fuck themselves.
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Re:How does an expensive SMS make them money?
The malware sets the phone to use third party SMS gateways
Those gateways deliver the SMS message to the recipient's carrier, and bills that carrier for the service. You might be none the wiser, but your carrier is paying for that incoming message via bilateral agreements or "Hubbing".
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PHP is pretty close to Perl ...
To my opinion, know Perl and you'll also know PHP; by watching the small differences. I've had a lesser feel for Javascript after doing extensive Perl works.
I'm coming from a Pascal and ASM background; barely touched C or C++ the last 10 years.