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SEARCH KEYWORD -- Fast fourier transform

  The faster-than-fast Fourier transform

The Fourier transform is one of the most fundamental concepts in the information sciences. It’s a method for representing an irregular signal — such as the voltage fluctuations in the wire that connects an MP3 player to a loudspeaker — as a combination of pure frequencies. It’s universal in signal processing, but it can also be used to compress image and audio files, solve differential equations and price stock options, among other things.The reason the Fourier...

   FFT,Fast fourier transform,MIT,Compression     2012-01-19 09:59:09

  How Speeding The "Most Important Algorithm Of Our Lifetime" Could Change This Modern World

Math breakthroughs don't often capture the headlines--but MIT researchers have just made one that could lead to all sorts of amazing technological breakthroughs that in just a few years will touch every hour of your life. Last week at the Association for Computing Machinery's Symposium on Discrete Algorithms (SODA) a new way of calculating Fast Fourier Transforms was presented by a group of MIT researchers. It's possible that under cert...

   FFT,Speed-up,Fast fourier transform     2012-03-20 07:47:04

  Code Optimization Techniques for Graphics Processing Units

Books on parallel programming theory often talk about such weird beasts like the PRAM model, a hypothetical hardware that would provide the programmer with a number of processors that is proportional to the input size of the problem at hand. Modern general purpose computers afford only a few processing units; four is currently a reasonable number. This limitation makes the development of highly parallel applications quite difficult to the average computer user. However, the low cost and th...

   Optimazation,GUI,Graphic processing     2011-12-18 01:11:53

  MySQL index optimization

Problem description: We need to access a very big table which has 40 million records. In the table, id is the primary key and program_id is indexed. When executing a select query: select * from program_access_log where program_id between 1 and 4000 The above query executes very slowly, we thought it was because there were too many records in the table. So we added id in the where condition to limit the search so that each time only half a million records would be read. select * fr...

   MySQL,Index search, Partition     2012-12-26 13:14:20

  Code coverage rate

When doing unit testing, the code coverage rate is often used as the criteria for measuring testing performance, even in some cases code coverage may be used to consider whether the testing task is completed or not. So testers need to spend much time on designing test cases which can cover as many codes as possible. There are advantages and disadvantages about using code coverage rate. First let's check what is code coverage rate: code coverage rate= the degree of code coverage in testing. There...

   Unit testing,Code coverage     2013-04-16 12:50:57

  Using JSON in PHP

Currently JSON has become one of the most popular data exchange formats. Many website APIs support it. Since PHP 5.2, PHP provides json_encode() and json_decode() method to handle JSON encoding and decoding.1. json_encode()This function is used to transform array and objects to JSON format. First let's look one array example.        $arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5); 　　echo json_encode($arr);the result is{"a":1,"b"...

   JSON,PHP,json_decode(0,json_encode()     2012-05-06 06:04:42

  What have been Facebook’s greatest technical accomplishments?

To maintain a large website which gets billions of requests er day and keeps very fast response speed is not an easy task. Many big companies are trying best to improve user experience by adopting different techniques. There is a question on Quora which asks "What have been Facebook’s greatest technical accomplishments?". There is a person who worked in Facebook before provided an answer which helps us understanding how Facebook handles huge amount of traffic each day. Here is the answer f...

   Facebook, Design, Efficiency     2013-01-15 07:32:07

  How ScrollerJS works

ScrollerJS is a light weight number scroller module to be embedded in web apps. It provides fancy number scrolling animations. ScrollerJS supports both CSS transition and DOM animation to handle the animation needed. If CSS transition is supported in a browser, CSS transition will be the preferred option for animation. If in old browsers where CSS transition is not supported. DOM animation will be chosen automatically. How does the number scrolling actually work? To transition a number from 0 to...

   ScrollerJS,JavaScript,CSS,GitHub     2015-06-11 06:54:44

  Some useful Linux commands for teamwork

A small development team in the intranet will frequently transfer codes, share files. Here are some command we use frequently to release some of our work. They are not applicable to Windows users. 1. Output program execution output through GTalk. Sometimes we may need to send the program execution result and log to teammates for debugging using IM. These outputs are very troublesome to copy and send while in command line mode. So we could have a program called gpipe.py which can put GTalk as a p...

   Linux,NFS,GTalk,HTTP     2013-01-16 04:36:33

  Ensure triggering transitionend event in JavaScript

CSS3 Transition has been widely used in modern web app development to offer users animations. Traditionally animations of element in HTML are controlled by JavaScript. If fancy animation is desired, then third party plugins can be installed in browsers such as Flash, Silverlight, Java Applet etc. With CSS3, animations can be easily achieved like a charm. Transition is one of the many features provided by CSS3. It can be used to transit one element from one state to another state smoothly within ...

   CSS3 TRANSITION, TRANSITIONEND, FORCE FIRE TRANSITIONEND     2015-05-09 08:56:51

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