Hello, I am facing an application that uses hashing, but I cannot still figure out how it works. Here is my problem, hashing is used to generate some index, and with those indexes I access to different tables, and after I add the value of every table that I get using the indexes and with that I get my final value. This is done to reduce...
I've recently started a course on data compression at my university. However, I find the use of the term "entropy" as it applies to computer science rather ambiguous. As far as I can tell, it roughly translates to the "randomness" of a system or structure. What is the proper definition of computer science "entropy"? ...
A start-step-stop code is a data compression technique that is used to compress number that are relatively small. The code works as follows: It has three parameters, start, step and stop. Start determines the amount of bits used to compute the first few numbers. Step determines how many bits to add to the encoding when we run out and s...
Does anyone know where I can find video/screencast tutorials on data compression? ...
Duplicate: audio and video file compressor I would like to compress a wmv 2mb or larger file to 3gp 250kb file for mobile devices. any great compressors for video or audio? ...
Suppose I have any data stored in bytes. For example: 0110001100010101100101110101101 How can I store it as printable text? The obvious way would be to convert every 0 to the character '0' and every 1 to the character '1'. In fact this is what I'm currently doing. I'd like to know how I could pack them more tightly, without losi...
Hi, I am to compress location data (latitude,longitude, date,time). All the numbers are in fixed format. 2 of them (latitude,longitude) are with decimal format. Other 2 are integers. Now these numbers are in fixed format string. What are the algorithms for compressing numbers in fixed format? Is number only compressions (if there any...
I'm looking for recommended resources on data compression; any studies on techniques, data structure and/or algorithms; any useful resources related to research, any books, organizations or any other information would be helpful. I know it's kind of a general query, but just interested in expanding my knowledge on the subject matter. ...
I have an array of point data, the values of points are represented as x co-ordinate and y co-ordinate. These points could be in the range of 500 upto 2000 points or more. The data represents a motion path which could range from the simple to very complex and can also have cusps in it. Can I represent this data as one spline or a coll...
I would like to gzip the html sources of my webpages, what's the best way to do it on a lighttpd/php5 server. I have tried to do it by editing my php.ini file with: zlib.output_compression = On zlib.output_handler = On but it seems to be a transparent compression only. ...
Hi , I am doing a web project on media manager. I upload high resolution images and need to convert these images to low resolution, so that the resulting image is compressed into a smaller size. How is this possible using Java? Please post source code, if possible. Thanks, Naveen ...
i have a task to compress a stock market data somehow...the data is in a file where the stock value for each day is given in one line and so on...so it's a really big file. Eg, 123.45 234.75 345.678 889.56 ..... now the question is how to compress the data (aka reduce the redundancy) using standard algorithms like Huffman or Arith...
file = BZ2File(SOME_FILE_PATH) p = xml.parsers.expat.ParserCreate() p.Parse(file) Here's code that tries to parse xml file compressed with bz2. Unfortunately it fails with a message: TypeError: Parse() argument 1 must be string or read-only buffer, not bz2.BZ2File Is there a way to parse on the fly compressed bz2 xml files? Note: p...
Hi, I have a X bytes file. And I want to compress it in block of size 32Kb, for example. Is there any lib that Can I do this? I used Zlib for Delphi but I just can compress a full file in new compressed file. Tranks a lot, Pedro ...
Is there a standard way to do this? Googling -- "approximate entropy" bits -- uncovers multiple academic papers but I'd like to just find a chunk of pseudocode defining the approximate entropy for a given bit string of arbitrary length. (In case this is easier said than done and it depends on the application, my application involves 16...
I wanted to compress my pages so I put ob_start('ob_gzhandler'); at the beginning of my php header file. however as I was playing around I noticed it will give me a blank page if I start a session while the ob_gzhandler was not being used! so I did the below and it worked: how ever I'm not sure if this will always use the compression a...
I would like to make "compressed array"/"compressed vector" class (details below), that allows random data access with more or less constant time. "more or less constant time" means that although element access time isn't constant, it shouldn't keep increasing when I get closer to certain point of the array. I.e. container shouldn't do ...
Possible Duplicate: Programming Logic: Finding the smallest equation to a large number. I'm looking for an algorithm that will take an arbitrary number from the Aleph-Null set (all positive integers)(likely to be absolutely enormous) and attempt to simplify it into a computable number (if the computable number takes up less sp...
Hello, In an application I've been working on, I have to send a 256 x 256 matrix over a socket. I'm developing a visualization client for a offshore system simulator that runs on a cluster, and this matrix is a heightmap representing the current state of the oceanic surface. This is an realtime application, so speed is a must. And, usi...
I have binary array in c, I want to compress the array, kindly suggest me algorithm which compress binary array. I have used Lempel–Ziv–Welch (LZW) algorithm but its not suitable for me because there is no repetition in my data. ...