Search Results

Search found 13226 results on 530 pages for 'extreme programming'.

Page 10/530 | < Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >

  • Your thoughts on Best Practices for Scientific Computing?

    - by John Smith
    A recent paper by Wilson et al (2014) pointed out 24 Best Practices for scientific programming. It's worth to have a look. I would like to hear opinions about these points from experienced programmers in scientific data analysis. Do you think these advices are helpful and practical? Or are they good only in an ideal world? Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, Haddock SHD, Huff KD, Mitchell IM, Plumbley MD, Waugh B, White EP, Wilson P (2014) Best Practices for Scientific Computing. PLoS Biol 12:e1001745. http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001745 Box 1. Summary of Best Practices Write programs for people, not computers. (a) A program should not require its readers to hold more than a handful of facts in memory at once. (b) Make names consistent, distinctive, and meaningful. (c) Make code style and formatting consistent. Let the computer do the work. (a) Make the computer repeat tasks. (b) Save recent commands in a file for re-use. (c) Use a build tool to automate workflows. Make incremental changes. (a) Work in small steps with frequent feedback and course correction. (b) Use a version control system. (c) Put everything that has been created manually in version control. Don’t repeat yourself (or others). (a) Every piece of data must have a single authoritative representation in the system. (b) Modularize code rather than copying and pasting. (c) Re-use code instead of rewriting it. Plan for mistakes. (a) Add assertions to programs to check their operation. (b) Use an off-the-shelf unit testing library. (c) Turn bugs into test cases. (d) Use a symbolic debugger. Optimize software only after it works correctly. (a) Use a profiler to identify bottlenecks. (b) Write code in the highest-level language possible. Document design and purpose, not mechanics. (a) Document interfaces and reasons, not implementations. (b) Refactor code in preference to explaining how it works. (c) Embed the documentation for a piece of software in that software. Collaborate. (a) Use pre-merge code reviews. (b) Use pair programming when bringing someone new up to speed and when tackling particularly tricky problems. (c) Use an issue tracking tool. I'm relatively new to serious programming for scientific data analysis. When I tried to write code for pilot analyses of some of my data last year, I encountered tremendous amount of bugs both in my code and data. Bugs and errors had been around me all the time, but this time it was somewhat overwhelming. I managed to crunch the numbers at last, but I thought I couldn't put up with this mess any longer. Some actions must be taken. Without a sophisticated guide like the article above, I started to adopt "defensive style" of programming since then. A book titled "The Art of Readable Code" helped me a lot. I deployed meticulous input validations or assertions for every function, renamed a lot of variables and functions for better readability, and extracted many subroutines as reusable functions. Recently, I introduced Git and SourceTree for version control. At the moment, because my co-workers are much more reluctant about these issues, the collaboration practices (8a,b,c) have not been introduced. Actually, as the authors admitted, because all of these practices take some amount of time and effort to introduce, it may be generally hard to persuade your reluctant collaborators to comply them. I think I'm asking your opinions because I still suffer from many bugs despite all my effort on many of these practices. Bug fix may be, or should be, faster than before, but I couldn't really measure the improvement. Moreover, much of my time has been invested on defence, meaning that I haven't actually done much data analysis (offence) these days. Where is the point I should stop at in terms of productivity? I've already deployed: 1a,b,c, 2a, 3a,b,c, 4b,c, 5a,d, 6a,b, 7a,7b I'm about to have a go at: 5b,c Not yet: 2b,c, 4a, 7c, 8a,b,c (I could not really see the advantage of using GNU make (2c) for my purpose. Could anyone tell me how it helps my work with MATLAB?)

    Read the article

  • What Functional features are worth a little OOP confusion for the benefits they bring?

    - by bonomo
    After learning functional programming in Haskell and F#, the OOP paradigm seems ass-backwards with classes, interfaces, objects. Which aspects of FP can I bring to work that my co-workers can understand? Are any FP styles worth talking to my boss about retraining my team so that we can use them? Possible aspects of FP: Immutability Partial Application and Currying First Class Functions (function pointers / Functional Objects / Strategy Pattern) Lazy Evaluation (and Monads) Pure Functions (no side effects) Expressions (vs. Statements - each line of code produces a value instead of, or in addition to causing side effects) Recursion Pattern Matching Is it a free-for-all where we can do whatever the programming language supports to the limit that language supports it? Or is there a better guideline?

    Read the article

  • Software development magazines [closed]

    - by Sebastian
    Ive spent the last hour or so browsing the web for professional development magazines. I am mostly interested in the java platform, agile methods, "programming in general" (tutorials on languages or whatever, "hot new stuff" etc) and software craftmanship. My best finding yet was pragpub and maybe MSDN magazine. I am willing to pay and have a Zinio account if anyone knows a magazine about programming that is distributed by them. Ive already browsed a couple of related threads here on stackexchange. ACM and IEEE does not seem relevant, as Im not interested in research articles. Maybe conferences like OOPSLA as somebody mentioned in another thread. PS. I prefer if they are in pdf or readable on kindle or a tablet. DS. BR Sebastian

    Read the article

  • Should a new programmer nowadays start with C/C++ or OOP language? [closed]

    - by deviDave
    I've been a programmer for 15+ years. In my time, we all started with C or C++ and then moved to C# or Java. At that time it was a usual practice. Now, my brother wants to follow my steps and I am not sure what advice to give him. So, I am asking the community for an opinion. Should nowadays new programmer with zero programming knowledge start with functional languages (C, C++, etc.) or he should start directly with OOP languages (Java, C#, etc.)? The reply should be considered in the context of my brother's future assignments. He will mainly work on Java mobile applications as well as ASP.NET web apps. He will have to touch with desktop apps, low level programming, drivers, etc. This is the reason I am not sure if he should ever need to learn functional languages.

    Read the article

  • Scheme vs Haskell for an Introduction to Functional Programming?

    - by haziz
    I am comfortable with programming in C and C#, and will explore C++ in the future. I may be interested in exploring functional programming as a different programming paradigm. I am doing this for fun, my job does not involve computer programming, and am somewhat inspired by the use of functional programming, taught fairly early, in computer science courses in college. Lambda calculus is certainly beyond my mathematical abilities, but I think I can handle functional programming. Which of Haskell or Scheme would serve as a good intro to functional programming? I use emacs as my text editor and would like to be able to configure it more easily in the future which would entail learning Emacs Lisp. My understanding, however, is that Emacs Lisp is fairly different from Scheme and is also more procedural as opposed to functional. I would likely be using "The Little Schemer" book, which I have already bought, if I pursue Scheme (seems to me a little weird from my limited leafing through it). Or would use the "Learn You a Haskell for Great Good" if I pursue Haskell. I would also watch the Intro to Haskell videos by Dr Erik Meijer on Channel 9. Any suggestions, feedback or input appreciated. Thanks. P.S. BTW I also have access to F# since I have Visual Studio 2010 which I use for C# development, but I don't think that should be my main criteria for selecting a language.

    Read the article

  • Spotlight on Claims: Serving Customers Under Extreme Conditions

    - by [email protected]
    Oracle Insurance's director of marketing for EMEA, John Sinclair, recently attended the CII Spotlight on Claims event in London. Bad weather and its implications for the insurance industry have become very topical as the frequency and diversity of natural disasters - including rains, wind and snow - has surged across Europe this winter. On England's wettest day on record, the county of Cumbria was flooded with 12 inches of rain within 24 hours. Freezing temperatures wreaked havoc on European travel, causing high speed TVG trains to break down and stranding hundreds of passengers under the English Chanel in a tunnel all night long without heat or electricity. A storm named Xynthia thrashed France and surrounding countries with hurricane force, flooding ports and killing 51 people. After the Spring Equinox, insurers may have thought the worst had past. Then came along Eyjafjallajökull, spewing out vast quantities of volcanic ash in what is turning out to be one of most costly natural disasters in history. Such extreme events challenge insurance companies' ability to service their customers just when customers need their help most. When you add economic downturn and competitive pressures to the mix, insurers are further stretched and required to continually learn and innovate to meet high customer expectations with reduced budgets. These and other issues were hot topics of discussion at the recent "Spotlight on Claims" seminar in London, focused on how weather is affecting claims and the insurance industry. The event was organized by the CII (Chartered Insurance Institute), a group with 90,000 members. CII has been at the forefront in setting professional standards for the insurance industry for over a century. Insurers came to the conference to hear how they could better serve their customers under extreme weather conditions, learn from the experience of their peers, and hear about technological breakthroughs in climate modeling, geographic intelligence and IT. Customer case studies at the conference highlighted the importance of effective and constant communication in handling the overflow of catastrophe related claims. First and foremost is the need to rapidly establish initial communication with claimants to build their confidence in a positive outcome. Ongoing communication then needs to be continued throughout the claims cycle to mange expectations and maintain ownership of the process from start to finish. Strong internal communication to support frontline staff was also deemed critical to successful crisis management, as was communication with the broader insurance ecosystem to tap into extended resources and business intelligence. Advances in technology - such web based systems to access policies and enter first notice of loss in the field - as well as customer-focused self-service portals and multichannel alerts, are instrumental in improving customer satisfaction and helping insurers to deal with the claims surge, which often can reach four or more times normal workloads. Dynamic models of the global climate system can now be used to better understand weather-related risks, and as these models mature it is hoped that they will soon become more accurate in predicting the timing of catastrophic events. Geographic intelligence is also being used within a claims environment to better assess loss reserves and detect fraud. Despite these advances in dealing with catastrophes and predicting their occurrence, there will never be a substitute for qualified front line staff to deal with customers. In light of pressures to streamline efficiency, there was debate as to whether outsourcing was the solution, or whether it was better to build on the people you have. In the final analysis, nearly everybody agreed that in the future insurance companies would have to work better and smarter to keep on top. An appeal was also made for greater collaboration amongst industry participants in dealing with the extreme conditions and systematic stress brought on by natural disasters. It was pointed out that the public oftentimes judged the industry as a whole rather than the individual carriers when it comes to freakish events, and that all would benefit at such times from the pooling of limited resources and professional skills rather than competing in silos for competitive advantage - especially the end customer. One case study that stood out was on how The Motorists Insurance Group was able to power through one of the most devastating catastrophes in recent years - Hurricane Ike. The keys to Motorists' success were superior people, processes and technology. They did a lot of upfront planning and invested in their people, creating a healthy team environment that delivered "max service" even when they were experiencing the same level of devastation as the rest of the population. Processes were rapidly adapted to meet the challenge of the catastrophe and continually adapted to Ike's specific conditions as they evolved. Technology was fundamental to the execution of their strategy, enabling them anywhere access, on the fly reassigning of resources and rapid training to augment the work force. You can learn more about the Motorists experience by watching this video. John Sinclair is marketing director for Oracle Insurance in EMEA. He has more than 20 years of experience in insurance and financial services.

    Read the article

  • Function-Local Static Const variable Initialization semantics.

    - by Hassan Syed
    The questions are in bold, for those that cannot be bothered reading a question in depth. This is a followup to this question. It is to do with the initialization semantics of static variables in functions. Static variables should be initialized once, and their internal state might be altered later - as I (currently) do in the linked question. However, the code in question does not require the feature to change the state of the variable later. Let me clarrify my position, since I don't require the string object's internal state to change. The code is for a trait class for meta programming, and as such would would benifit from a const char * const ptr -- thus Ideally a local cost static const variable is needed. My educated guess is that in this case the string in question will be optimally placed in memory by the link-loader, and that the code is more secure and maps to the intended semantics. This leads to the semantics of such a variable "The C++ Programming language Third Edition -- Stroustrup" does not have anything (that I could find) to say about this matter. All that is said is that the variable is initialized once when the flow of control of the thread first reaches the code. This leads me to ponder if the following code would be sensible, and if not what are the intended semantics ?. #include <iostream> const char * const GetString(const char * x_in) { static const char * const x = x_in; return x; } int main() { const char * const temp = GetString("yahoo"); std::cout << temp << std::endl; const char * const temp2 = GetString("yahoo2"); std::cout << temp2 << std::endl; } The following compiles on GCC and prints "yahoo" twice. Which is what I want -- However it might not be standards compliant (which is why I post this question). It might be more elegant to have two functions, "SetString" and "String" where the latter forwards to the first. If it is standards compliant does someone know of a templates implementation in boost (or elsewhere) ?

    Read the article

  • Understanding the 'High Performance' meaning in Extreme Transaction Processing

    - by kyap
    Despite my previous blogs entries on SOA/BPM and Identity Management, the domain where I'm the most passionated is definitely the Extreme Transaction Processing, commonly called XTP.I came across XTP back to 2007 while I was still FMW Product Manager in EMEA. At that time Oracle acquired a company called Tangosol, which owned an unique product called Coherence that we renamed to Oracle Coherence. Beside this innovative renaming of the product, to be honest, I didn't know much about it, except being a "distributed in-memory cache for Extreme Transaction Processing"... not very helpful still.In general when people doesn't fully understand a technology or a concept, they tend to find some shortcuts, either correct or not, to justify their lack-of understanding... and of course I was part of this category of individuals. And the shortcut was "Oracle Coherence Cache helps to improve Performance". Excellent marketing slogan... but not very meaningful still. By chance I was able to get away quickly from that group in July 2007* at Thames Valley Park (UK), after I attended one of the most interesting workshops, in my 10 years career in Oracle, delivered by Brian Oliver. The biggest mistake I made was to assume that performance improvement with Coherence was related to the response time. Which can be considered as legitimus at that time, because after-all caches help to reduce latency on cached data access, hence reduce the response-time. But like all caches, you need to define caching and expiration policies, thinking about the cache-missed strategy, and most of the time you have to re-write partially your application in order to work with the cache. At a result, the expected benefit vanishes... so, not very useful then?The key mistake I made was my perception or obsession on how performance improvement should be driven, but I strongly believe this is still a common problem to most of the developers. In fact we all know the that the performance of a system is generally presented by the Capacity (or Throughput), with the 2 important dimensions Speed (response-time) and Volume (load) :Capacity (TPS) = Volume (T) / Speed (S)To increase the Capacity, we can either reduce the Speed(in terms of response-time), or to increase the Volume. However we tend to only focus on reducing the Speed dimension, perhaps it is more concrete and tangible to measure, and nicer to present to our management because there's a direct impact onto the end-users experience. On the other hand, we assume the Volume can be addressed by the underlying hardware or software stack, so if we need more capacity (scale out), we just add more hardware or software. Unfortunately, the reality proves that IT is never as ideal as we assume...The challenge with Speed improvement approach is that it is generally difficult and costly to make things already fast... faster. And by adding Coherence will not necessarily help either. Even though we manage to do so, the Capacity can not increase forever because... the Speed can be influenced by the Volume. For all system, we always have a performance illustration as follow: In all traditional system, the increase of Volume (Transaction) will also increase the Speed (Response-Time) as some point. The reason is simple: most of the time the Application logics were not designed to scale. As an example, if you have a while-loop in your application, it is natural to conceive that parsing 200 entries will require double execution-time compared to 100 entries. If you need to "Speed-up" the execution, you can only upgrade your hardware (scale-up) with faster CPU and/or network to reduce network latency. It is technically limited and economically inefficient. And this is exactly where XTP and Coherence kick in. The primary objective of XTP is about designing applications which can scale-out for increasing the Volume, by applying coding techniques to keep the execution-time as constant as possible, independently of the number of runtime data being manipulated. It is actually not just about having an application running as fast as possible, but about having a much more predictable system, with constant response-time and linearly scale, so we can easily increase throughput by adding more hardwares in parallel. It is in general combined with the Low Latency Programming model, where we tried to optimize the network usage as much as possible, either from the programmatic angle (less network-hoops to complete a task), and/or from a hardware angle (faster network equipments). In this picture, Oracle Coherence can be considered as software-level XTP enabler, via the Distributed-Cache because it can guarantee: - Constant Data Objects access time, independently from the number of Objects and the Coherence Cluster size - Data Objects Distribution by Affinity for in-memory data grouping - In-place Data Processing for parallel executionTo summarize, Oracle Coherence is indeed useful to improve your application performance, just not in the way we commonly think. It's not about the Speed itself, but about the overall Capacity with Extreme Load while keeping consistant Speed. In the future I will keep adding new blog entries around this topic, with some sample codes experiences sharing that I capture in the last few years. In the meanwhile if you want to know more how Oracle Coherence, I strongly suggest you to start with checking how our worldwide customers are using Oracle Coherence first, then you can start playing with the product through our tutorial.Have Fun !

    Read the article

  • Microsoft .NET Web Programming: Web Sites versus Web Applications

    - by SAMIR BHOGAYTA
    In .NET 2.0, Microsoft introduced the Web Site. This was the default way to create a web Project in Visual Studio 2005. In Visual Studio 2008, the Web Application has been restored as the default web Project in Visual Studio/.NET 3.x The Web Site is a file/folder based Project structure. It is designed such that pages are not compiled until they are requested ("on demand"). The advantages to the Web Site are: 1) It is designed to accommodate non-.NET Applications 2) Deployment is as simple as copying files to the target server 3) Any portion of the Web Site can be updated without requiring recompilation of the entire Site. The Web Application is a .dll-based Project structure. ASP.NET pages and supporting files are compiled into assemblies that are then deployed to the target server. Advantages of the Web Application are: 1) Precompiled files do not expose code to an attacker 2) Precompiled files run faster because they are binary data (the Microsoft Intermediate Language, or MSIL) executed by the CLR (Common Language Runtime) 3) References, assemblies, and other project dependencies are built in to the compiled site and automatically managed. They do not need to be manually deployed and/or registered in the Global Assembly Cache: deployment does this for you If you are planning on using automated build and deployment, such as the Team Foundation Server Team Build engine, you will need to have your code in the form of a Web Application. If you have a Web Site, it will not properly compile as a Web Application would. However, all is not lost: it is possible to work around the issue by adding a Web Deployment Project to your Solution and then: a) configuring the Web Deployment Project to precompile your code; and b) configuring your Team Build definition to use the Web Deployment Project as its source for compilation. https://msevents.microsoft.com/cui/WebCastEventDetails.aspx?culture=en-US&EventID=1032380764&CountryCode=US

    Read the article

  • programming practices starting

    - by Tamim Ad Dari
    I have taken my major as computer science and Engineering and I am really confused at this moment. My first course was about learning C and C++ and I learned the basics of those. Now I am really confused what to do next. Some says I should practice algorithms and do contests in ACM-ICPC for now. Others tell me to start software development. But As I started digging its really a vast topic and there are many aspects of these, like web design, web-development, iOS-development, android... etc many things. And I am really confused about what should I do just now. Any advice for me to start with?

    Read the article

  • How do you research while pair programming?

    - by traffichazard
    I've recently started at a new job and pairing has helped me become effective there very quickly. I am, however, having a hard time when we must do brief joint research during our workflow, covering API features, code examples, or command options. My team lead urges us to do all research on our pairing station, rather than our individual laptops, and to synchronize our research by verbally negotiating the steps between different web resources. I research, read, and absorb information differently from my pairing partner, and I feel much more productive when I can follow a thread of research to the next web page exactly when I want to, rather than trying to keep exact pace and place with what my partner's reading. We're both smart and fast, but we can't help moving in different ways and instantaneous velocities when we're figuring stuff out. It seems so much easier to poke around individually for a minute until one of us says "I've got it," then get back together and code. When you pair program, how do you handle short research tasks? What works best for you, and how to you keep in sync with your partner?

    Read the article

  • Dangerous programming

    - by benhowdle89
    Ok, i'm talking pure software/web, i'm not on about code to power Life Support machines or NASA rockets. In terms of software/web development what is the most dangerous single piece of code someone could put into a program (say if they had a grudge against a client/employee) In PHP, the first thing that comes to mind is some sort of file deletion: function EmptyDir($dir) { $handle=opendir($dir); while (($file = readdir($handle))!==false) { echo "$file <br>"; @unlink($dir.'/'.$file); } closedir($handle); } EmptyDir('images'); Or a PHP script that takes a user's sensitive input and posts it to Google sitemap or something? I hope this doesnt get closed off as subjective as there surely must be a ranking order of dangerous code. So i'm asking for the No.1 spot :) DISCLAIMER: I have no grudges against anyone, just curious for the answer!

    Read the article

  • Defensive Programming Techniques.

    - by Pemdas
    I was attempting to identify an element of software engineering that I think is overlooked, not emphasized or not taught in typical undergraduate course work for CS or SE. What I came up is the concept of defensive programing. I would like to hear the communities options on defensive program and/or specific techniques that you use on a regular basis. Also, I would to know if there are any language specific techniques.

    Read the article

  • Is the C programming language still used?

    - by Pankaj Upadhyay
    I am a C# programmer, and most of my development is for websites along with a few Windows application. As far as C goes, I haven't used it in a long time, as there was no need to. It came to me as a surprise when one of my friends said that she needs to learn C for testing jobs, while I was helping her learn C#. I figured that someone would only learn C for testing only if there is development done in C. In my knowledge, all the development related to COM and hardware design are also done in C++. Therefore, learning C doesn't make sense if you need to use C++. I also don't believe in historic significance, so why waste time and money in learning C? Is C is still used in any kind of new software development or anything else?

    Read the article

  • Procedural, Semi-Procedural and Declarative Programming in SQL

    A lot of the time, the key to making SQL databases perform well is to take a break from the keyboard and rethink the way of approaching the problem; and rethinking in terms of a set-based declarative approach. Joe takes a simple discussion abut a problem with a UDF to illustrate the point that ingrained procedural reflexes can often prevent us from seeing simpler set-based techniques.

    Read the article

  • What are functional-programming ways of implementing Conway's Game of Life

    - by George Mauer
    I recently implemented for fun Conway's Game of Life in Javascript (actually coffeescript but same thing). Since javascript can be used as a functional language I was trying to stay to that end of the spectrum. I was not happy with my results. I am a fairly good OO programmer and my solution smacked of same-old-same-old. So long question short: what is the (pseudocode) functional style of doing it? Here is Pseudocode for my attempt: class Node update: (board) -> get number_of_alive_neighbors from board get this_is_alive from board if this_is_alive and number_of_alive_neighbors < 2 then die if this_is_alive and number_of_alive_neighbors > 3 then die if not this_is_alive and number_of_alive_neighbors == 3 then alive class NodeLocations at: (x, y) -> return node value at x,y of: (node) -> return x,y of node class Board getNeighbors: (node) -> use node_locations to check 8 neighbors around node and return count nodes = for 1..100 new Node state = new NodeState(nodes) locations = new NodeLocations(nodes) board = new Board(locations, state) executeRound: state = clone state accumulated_changes = for n in nodes n.update(board) apply accumulated_changes to state board = new Board(locations, state)

    Read the article

  • Programming Geek's CV Design

    - by benhowdle89
    What is the best practice or advice for a programmer's CV? If I were a graphic designer or more of a web designer as opposed to a programmer, then I'd imagine a CV would have a bit more flourish to it. Yet as a programmer, aren't we judged on not only efficiency and results but also creativity, imagination and initiative? Should this be reflected in a CV? Or is it all about the information, no wishy washy designs in sight? Has anyone experimented with an original alternative to a PDF CV with a template from MS Word or Mac Pages?

    Read the article

  • Basic Defensive Database Programming Techniques

    We can all recognise good-quality database code: It doesn't break with every change in the server's configuration, or on upgrade. It isn't affected by concurrent usage, or high workload. In an extract from his forthcoming book, Alex explains just how to go about producing resilient TSQL code that works, and carries on working.

    Read the article

  • Functional programming readability

    - by Jimmy Hoffa
    I'm curious about this because I recall before learning any functional languages, I thought them all horribly, awfully, terribly unreadable. Now that I know Haskell and f#, I find it takes a little longer to read less code, but that little code does far more than an equivalent amount would in an imperative language, so it feels like a net gain and I'm not extremely practiced in functional. Here's my question, I constantly hear from OOP folks that functional style is terribly unreadable. I'm curious if this is the case and I'm deluding myself, or if they took the time to learn a functional language, the whole style would no longer be more unreadable than OOP? Has anybody seen any evidence or got any anecdotes where they saw this go one way or another with frequency enough to possibly say? If writing functionally really is of lower readability than I don't want to keep using it, but I really don't know if that's the case or not..

    Read the article

  • learn the programming language for computing functions about integers

    - by asd
    Hi I know something about Pascal, Mathematica and Matlab, but I dont have any idea about C,C++,C# languages. I want to learn one of the languages that they they are fast and exact to compute some arithmetic functions for large numbers(for example larger than $10^3000$). I asked somebody and he said he used C++ and he said I computed this sequence in less than 10 min. I want to know C, C++, C# and visual kind of theses programs and know which is better for my goal. Let $f$ be an arithmetic function and A={k1,k2,...,kn} are integers in increasing order. Now I want to start with k1 and compare f(ki) with f(k1). If f(ki)f(k1), put ki as k1. Now start with ki, and compare f(kj) with f(ki), for ji. If f(kj)f(ki), put kj as ki, and repeat this procedure. At the end we will have a sub sequence B={L1,...,Lm} of A by this property: f(L(i+1))f(L(i)), for any 1<=i<=m-1 I have written a code for this program with Mathematica, and it take some hours to compute f of ki's or the set B for large numbers. For example, let f is the divisor function of integers. Do you know how to write the code for my purpose in Mathematica or Matlab. Mathematica is preferable.

    Read the article

  • Yet another use of OUTER APPLY in defensive programming

    - by Alexander Kuznetsov
    When a SELECT is used to populate variables from a subquery, it fails to change them if the subquery returns nothing - and that can lead to subtle bugs. We shall use OUTER APPLY to eliminate this problem. Prerequisites All we need is the following mock function that imitates a subquery: CREATE FUNCTION dbo.BoxById ( @BoxId INT ) RETURNS TABLE AS RETURN ( SELECT CAST ( 1 AS INT ) AS [Length] , CAST ( 2 AS INT ) AS [Width] , CAST ( 3 AS INT ) AS [Height] WHERE @BoxId = 1 ) ; Let us assume that this...(read more)

    Read the article

  • A programming language that does not allow IO. Haskell is not a pure language

    - by TheIronKnuckle
    (I asked this on Stack Overflow and it got closed as off-topic, I was a bit confused until I read the FAQ, which discouraged subjective theoratical debate style questions. The FAQ here doesn't seem to have a problem with it and it sounds like this is a more appropriate place to post. If this gets closed again, forgive me, I'm not trying to troll) Are there any 100% pure languages (as I describe in the Stack Overflow post) out there already and if so, could they feasibly be used to actually do stuff? i.e. do they have an implementation? I'm not looking for raw maths on paper/Pure lambda calculus. However Pure lambda calculus with a compiler or a runtime system attached is something I'd be interested in hearing about.

    Read the article

  • Is using ELSE bad programming?

    - by dave.b
    I've often come across bugs that have been caused by using the ELSE construct. A prime example is something along the lines of: If (passwordCheck() == false){ displayMessage(); }else{ letThemIn(); } To me this screams security problem. I know that passwordCheck is likely to be a boolean, but I wouldn't place my applications security on it. What would happen if its a string, int etc? I usually try to avoid using ELSE, and instead opt for two completely separate IF statements to test for what I expect. Anything else then either gets ignored OR is specifically handled. Surely this is a better way to prevent bugs / security issues entering your app. How do you guys do it?

    Read the article

  • Is there any officially recognized, specific determinants that make a language programming/scripting?

    - by Dan
    I remember when I was first learning web-based programming everyone was intent on JavaScript not being a "programming language," but rather a scripting language; I have not heard that argument in quite a while now. I hear a lot of languages, like perl for example, referred to at different times as both a scripting and programming language. I know that a scripting language is less capable than a programming language, but where exactly does the line lie? Citation would be appreciated.

    Read the article

< Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >