SEARCH KEYWORD -- DATA ENGINEERING

  Translating math into code with examples in Java, Racket, Haskell and Python

Discrete mathematical structures form the foundation of computer science.These structures are so universal that most research papers in the theory of computation, programming languages and formal methods present concepts in terms of discrete mathematics rather than code.The underlying assumption is that the reader will know how to translate these structures into a faithful implementation as a working program.A lack of material explaining this translation frustrates outsiders.What deepens that fr...

   Math,Algorithms,Formula,Program,Python     2011-11-14 08:43:15

  OpenLDAP Proxy -- rwm-map vs map

OpenLDAP proxy is used to proxy ldap request and response between clients and servers, different servers may have different representations/attributes to mean the same thing. For example, in one LDAP server, the firstName may be represented by firstName, it may be represented by givenName in a different server. However, from the client perspective, it only wants to get the firstName, it doesn't care about the backend attributes. In this case, attribute mapping can help provide a virtual view of ...

   MAP,OPENLDAP,OPENLDAP PROXY,LDAP,RWM-MAP     2018-02-02 20:36:02

  Automate Everything

Performing manual, repetitive tasks enrages me. I used to think this was a corollary of being a programmer, but I’ve come to suspect (or hope) that this behaviour is inherent in being human. But being able to hack together scripts simply makes it much easier to go from a state of rage to a basic solution in a very small amount of time. As a side point, this is one of the reasons that teaching the basics of programming in schools is so important. It’s hard to think of any j...

   Automate,Email,Repeative     2012-02-07 06:21:19

  Why cannot compare double values directly for equality?

A question in PHP: Get some value from the database and use floatval() to convert it to floatint point value, then compare it with another value which is also converted to floating point value with floatval(). These two values are the same when using var_dump() to output, the two outputs are float(8.87), they are the same. But when comparing them for equality, the result is weird., they are not equal. Why?To analyze this question, we need to start with PHP data types. PHP uses weak types. In PHP...

   PHP,floating, precision,compare,equality     2012-06-27 09:01:36

  Javascript motion tracking

It is very often that I have to do video motion tracking for interactive video campaign in my daily work. If I’m used used to do that in Flash, I made a quick experiment to do the same in javascript. Thanks to Olof Storm who made me a perfect corner pin motion tracking in After Effects, and I’ve been using some code from Steven Wittens to draw an image in perspective. Click here to see the motion tracking demo (give it a bit of time to fully load). What I’m doing in this dem...

   JavaScript,Motion tracking,Flash     2012-03-20 07:43:46

  HP To Apple: You Win.

As I write this, I’m sitting in a cafe. Around me, there are five people on laptops — four of them are MacBooks. Four other people are using tablets — all four are iPads. Welcome to the Post-PC world. That phrase was one of the first things that jumped to my mind today when I heard the news that HP was not only killing off their TouchPad and Pre webOS-based products, but also trying to spin-off their PC business. The largest PC busine...

   HP,Apple,Palm,Competition,webOs     2011-08-19 07:38:41

  As A Hottest Job Ever, What Should You Know As A Front End Web Developer?

The front end web developers are the openers for the visitors to visit the web page. It is also known as the client-side development, works predominantly with HTML, CSS, and Javascript. The tools and techniques are the important players of the front end web development. The developer must be aware of the updation of web technologies.The scope is evergreen with this technology as every company or business needs a website to showcase their profile. There are many objectives must be measured while ...

   FRONT END DEVELOPER,WEB DEVELOPERS,SOFTWARE DEVELOPERS,TOP SOFTWARE COMPANIES     2019-08-12 05:36:28

  Is Shared Hosting Secure?

Shared hosting is incredibly popular with users who are looking for the cheapest hosting available – the problem is that along with the low price you get poor performance and even more concerning – questionable security. When running on a shared host dozens if not hundreds of other sites are running on the same servers – this means any single security flaw in any of those applications can compromise the entire server. This  dramatically increases the odds of your ...

   Shared hosting,Virtual host,Security,Data security     2012-02-14 10:48:59

  How big are PHP arrays (and values) really? (Hint: BIG!)

Upfront I want to thank Johannes and Tyrael for their help in finding some of the more hidden memory usage. In this post I want to investigate the memory usage of PHP arrays (and values in general) using the following script as an example, which creates 100000 unique integer array elements and measures the resulting memory usage: <?php $startMemory = memory_get_usage(); $array = range(1, 100000); echo memory_get_usage() - $startMemory, ' bytes'; How much would you expect it to ...

   PHP,Array,Memory occupation,Garbage collection     2011-12-16 10:06:04

  Programming Language Readability

Lets compare some Python to Haskell for solving the same problem.  The problem we’ll pick is Trie data-structure for auto-completions.  We are interested not so much in the nitty gritty of the algorithm, but in the language style itself.  Auto-complete has been in the programming news a lot recently; both a Python and a Haskell solver have turned up. (I suspect this post got flagged on Hacker News :(  It never got on the front-page despite the rapid upvoting on a n...

   Programming,Readability,Python,Haskell     2012-02-27 04:52:02

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