Search Results

Search found 10417 results on 417 pages for 'large'.

Page 220/417 | < Previous Page | 216 217 218 219 220 221 222 223 224 225 226 227  | Next Page >

  • DIA2012

    - by Chris Kawalek
    If you've read this blog before, you probably know that Oracle desktop virtualization is used to demonstrate Oracle Applications at many different trade shows. This week, the Oracle desktop team is at DIA2012 in Philadelphia, PA. The DIA conference is a large event, hosting about 7,000 professionals in the pharmaceutical, bio technology, and medical device fields. Healthcare and associated fields are leveraging desktop virtualization because the model is a natural fit due to their high security requirements. Keeping all the data on the server and not distributing it on laptops or PCs that could be stolen makes a lot of sense when you're talking about patient records and other sensitive information. We're proud to be supporting the Oracle Health Sciences team at DIA2012 by hosting all of the Oracle healthcare related demos on a central server, and providing simple, smart card based access using our Sun Ray Clients. And remember that you're not limited to using just Sun Ray Clients--you can also use the Oracle Virtual Desktop Client and freely move your session from your iPad, your Windows or Linux PC, your Mac, or Sun Ray Clients. It's a truly mobile solution for an industry that requires mobile, secure access in order to remain compliant. Here are some pics from the show: We also have an informative PDF on Oracle desktop virtualization and Oracle healthcare that you can have a look at.  (Many thanks to Adam Workman for the pics!) -Chris  For more information, please go to the Oracle Virtualization web page, or  follow us at :  Twitter   Facebook YouTube Newsletter

    Read the article

  • We're Subversion Geeks and we want to know the benefits of Mercurial

    - by Matt
    Having read I'm a Subversion geek, why should I consider or not consider Mercurial or Git or any other DVCS. I have a related follow up question. I read that question and read the recommended links and videos and I see the benefits but I don't see the overall mindshift people are talking about. Our team is of 8-10 developers that work on one large code base consisting of 60 projects. We use Subversion and have a main trunk. When a developer starts a new Fogbugz case they create a svn branch, do the work on the branch and when they're done they merge back to the trunk. Occasionally they may stay on the branch for an extended time and merge the trunk to the branch to pick up the changes. When I watched Linus talk about people creating a branch and never doing it again, that's not us at all. We create probably 50-100 branches a week without issue. The biggest challenge is the merging but we've gotten pretty good at that as well. I tend to merge by fogbugz case & checkin rather than the entire root of the branch. We never work remotely and we never make branches off of branches. If you're the only one working in that section of the code base then the merge to the trunk goes smoothly. If someone else had modified the same section of code then the merge can get messy and you might need to do some surgery. Conflicts are conflicts, I don't see how any system could get it right most of the time unless if was smart enough to understand the code. After creating a branch the following checkout of 60k+ files takes some time but that would be an issue with any source control system we'd use. Is there some benefit of any DVCS that we're not seeing that would be of great help to us?

    Read the article

  • When does the "Do One Thing" paradigm become harmful?

    - by Petr
    For the sake of argument here's a sample function that prints contents of a given file line-by-line. Version 1: void printFile(const string & filePath) { fstream file(filePath, ios::in); string line; while (file.good()) { getline(file, line); cout << line << endl; } } I know it is recommended that functions do one thing at one level of abstraction. To me, though code above does pretty much one thing and is fairly atomic. Some books (such as Robert C. Martin's Clean Code) seem to suggest breaking the above code into separate functions. Version 2: void printLine(const string & line) { cout << line << endl; } void printLines(fstream & file) { string line; while (file.good()) { getline(file, line); printLine(line); } } void printFile(const string & filePath) { fstream file(filePath, ios::in); printLines(file); } I understand what they want to achieve (open file / read lines / print line), but isn't it a bit of overkill? The original version is simple and in some sense already does one thing - prints a file. The second version will lead to a large number of really small functions which may be far less legible than the first version. Wouldn't it be, in this case, better to have the code at one place? At which point does the "Do One Thing" paradigm become harmful?

    Read the article

  • Splitting big request in multiple small ajax requests

    - by Ionut
    I am unsure regarding the scalability of the following model. I have no experience at all with large systems, big number of requests and so on but I'm trying to build some features considering scalability first. In my scenario there is a user page which contains data for: User's details (name, location, workplace ...) User's activity (blog posts, comments...) User statistics (rating, number of friends...) In order to show all this on the same page, for a request there will be at least 3 different database queries on the back-end. In some cases, I imagine that those queries will be running quite a wile, therefore the user experience may suffer while waiting between requests. This is why I decided to run only step 1 (User's details) as a normal request. After the response is received, two ajax requests are sent for steps 2 and 3. When those responses are received, I only place the data in the destined wrappers. For me at least this makes more sense. However there are 3 requests instead of one for every user page view. Will this affect the system on the long term? I'm assuming that this kind of approach requires more resources but is this trade of UX for resources a good dial or should I stick to one plain big request?

    Read the article

  • Making a perfect map (not tile-based)

    - by Sri Harsha Chilakapati
    I would like to make a map system as in the GameMaker and the latest code is here. I've searched a lot in google and all of them resulted in tutorials about tile-maps. As tile maps do not fit for every type of game and GameMaker uses tiles for a different purpose, I want to make a "Sprite Based" map. The major problem I had experienced was collision detection being slow for large maps. So I wrote a QuadTree class here and the collision detection is fine upto 50000 objects in the map without PixelPerfect collision detection and 30000 objects with PixelPerferct collisions enabled. Now I need to implement the method "isObjectCollisionFree(float x, float y, boolean solid, GObject obj)". The existing implementation is becoming slow in Platformer games and I need suggestions on improvement. The current Implementation: /** * Checks if a specific position is collision free in the map. * * @param x The x-position of the object * @param y The y-position of the object * @param solid Whether to check only for solid object * @param object The object ( used for width and height ) * @return True if no-collision and false if it collides. */ public static boolean isObjectCollisionFree(float x, float y, boolean solid, GObject object){ boolean bool = true; Rectangle bounds = new Rectangle(Math.round(x), Math.round(y), object.getWidth(), object.getHeight()); ArrayList<GObject> collidables = quad.retrieve(bounds); for (int i=0; i<collidables.size(); i++){ GObject obj = collidables.get(i); if (obj.isSolid()==solid && obj != object){ if (obj.isAlive()){ if (bounds.intersects(obj.getBounds())){ bool = false; if (Global.USE_PIXELPERFECT_COLLISION){ bool = !GUtil.isPixelPerfectCollision(x, y, object.getAnimation().getBufferedImage(), obj.getX(), obj.getY(), obj.getAnimation().getBufferedImage()); } break; } } } } return bool; } Thanks.

    Read the article

  • Oracle Internet Directory 11gR1 11.1.1.6 Certified with Oracle E-Business Suite

    - by B Shashikumar
    We are very pleased to announce that Oracle Internet Directory 11gR1 (11.1.1.6) is now certified with Oracle E-Business Suite Releases 11i, 12.0 and 12.1. With this certification, we are offering several benefits to Oracle E-Business Suite customers: · Massive Scale: Oracle Internet Directory (OID) is a proven solution for mission critical deployments. OID can scale to extremely large deployments on less hardware as demonstrated by its published Two-Billion-User Benchmark. This reduces the footprint required to deploy enterprise directory services in the data-center resulting in cost savings and a greener enterprise. · Enhanced Security: OID is the most secure directory service that provides security at every level from data in transit to storage and backups. In addition to LDAP security, it leverages powerful Oracle database security features like Database Vault and Transparent Data Encryption · Investment Protection: This certification leverages Identity Management’s hot-pluggable capabilities enabling E-Business Suite customers to store and manage user identities in existing directory servers thus helping them maximize their investments For a complete matrix of platforms supported by Oracle Internet Directory and its components, refer to the Oracle Identity and Access Management 11gR1 certification matrix. For more information about this certification, check out the Oracle E-Business Suite blog. 

    Read the article

  • How Service Component Architecture (SCA) Can Be Incorporated Into Existing Enterprise Systems

    After viewing Rob High’s presentation “The SOA Component Model” hosted on InfoQ.com, I can foresee how Service Component Architecture (SCA) can be incorporated in to an existing enterprise. According to IBM’s DeveloperWorks website, SCA is a set of conditions which outline a model for constructing applications/systems using a Service-Oriented Architecture (SOA). In addition, SCA builds on open standards such as Web services. In the future, I can easily see how some large IT shops could potently divide development teams or work groups up into Component/Data Object Groups, and Standard Development Groups. The Component/Data Object Group would only work on creating and maintaining components that are reused throughout the entire enterprise. The Standard Development Group would work on new and existing projects that incorporate the use of various components to accomplish various business tasks. In my opinion the incorporation of SCA in to any IT department will initially slow down the number of new features developed due to the time needed to create the new and loosely-coupled components. However once a company becomes more mature in its SCA process then the number of program features developed will greatly increase. I feel this is due to the fact that the loosely-coupled components needed in order to add the new features will already be built and ready to incorporate into any new development feature request. References: BEA Systems, Cape Clear Software, IBM, Interface21, IONA Technologies PLC, Oracle, Primeton Technologies Ltd, Progress Software, Red Hat Inc., Rogue Wave Software, SAP AG, Siebel Systems, Software AG, Sun Microsystems, Sybase, TIBCO Software Inc. (2006). Service Component Architecture. Retrieved 11 27, 2011, from DeveloperWorks: http://www.ibm.com/developerworks/library/specification/ws-sca/ High, R. (2007). The SOA Component Model. Retrieved 11 26, 2011, from InfoQ: http://www.infoq.com/presentations/rob-high-sca-sdo-soa-programming-model

    Read the article

  • How should I deal with user agent parsing in logs?

    - by Mr. Jefferson
    My web app project includes logging functionality so we can see where visitors are coming from (referrer URL), what the popular user agents are, what pages are most popular, etc. The log is stored in SQL Server, and when I query the user agents I use a large (almost 100 lines) and growing CASE statement to separate the user agents using string matching (i.e. if the user agent contains the string "Firefox/9" then it's Firefox 9). Is there a better way to do this so I don't have to continually add to that CASE statement to deal with new browser releases? Also, how should I deal with less common, weird/unknown user agents? I've seen the following in the logs and been unable to find good information online about what they are: WordPress/3.3.1; http://www.facecolony.org Mozilla/4.0 ( http://www.hairirons.org redips; <a href=http://hairirons.org/>chi hair iron</a>) I'd guess they're bots/crawlers, but the sites they point to don't appear to reference web crawlers (or even be available sometimes). I've seen other user agents aren't familiar to me, but I know they're bots because they include "bot" or "spider" or something similar in them.

    Read the article

  • Frequent disconnects with oneiric server using wlan AR9285

    - by John Neil
    I'm getting a large number of disconnects from my wireless when I switched to oneiric server (I did not see these happen with oneiric desktop) from my AR9285 wireless LAN device. Here is the syslog snippet: Oct 17 09:43:17 weather kernel: [ 1537.329138] wlan0: deauthenticated from 00:12:17:7a:8e:42 (Reason: 7) Oct 17 09:43:17 weather kernel: [ 1537.340409] cfg80211: All devices are disconnected, going to restore regulatory settings Oct 17 09:43:17 weather kernel: [ 1537.340423] cfg80211: Restoring regulatory settings Oct 17 09:43:17 weather kernel: [ 1537.340435] cfg80211: Calling CRDA to update world regulatory domain Oct 17 09:43:17 weather kernel: [ 1537.348571] cfg80211: Ignoring regulatory request Set by core since the driver uses its own custom regulatory domain Oct 17 09:43:17 weather kernel: [ 1537.348581] cfg80211: World regulatory domain updated: Oct 17 09:43:17 weather kernel: [ 1537.348586] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp) Oct 17 09:43:17 weather kernel: [ 1537.348594] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) Oct 17 09:43:17 weather kernel: [ 1537.348600] cfg80211: (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) Oct 17 09:43:17 weather kernel: [ 1537.348607] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm) Oct 17 09:43:17 weather kernel: [ 1537.348613] cfg80211: (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) Oct 17 09:43:17 weather kernel: [ 1537.348620] cfg80211: (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm) Here is the relevant lspci output: # lspci | grep Atheros 02:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01) I have done quite a bit of searching and saw discussions for previous versions of ubuntu that recommended installing the linux-backports-modules package. However, this does not appear to be available for oneiric (just the headers are listed as a package). Any advice on how to achieve a stable wireless connection for this server? It's location mitigates against using a wired connection.

    Read the article

  • Static "LoD" hack opinions

    - by David Lively
    I've been playing with implementing dynamic level of detail for rendering a very large mesh in XNA. It occurred to me that (duh) the whole point of this is to generate small triangles close to the camera, and larger ones far away. Given that, rather than constantly modifying or swapping index buffers based on a feature's rendered size or distance from the camera, it would be a lot easier (and potentially quite a bit faster), to render a single "fan" or flat wedge/frustum-shaped planar mesh that is tessellated into small triangles close to the near or small end of the frustum and larger ones at the far end, sort of like this (overhead view) (Pardon the gap in the middle - I drew one side and mirrored it) The triangle sizes are chosen so that all are approximately the same size when projected. Then, that mesh would be transformed to track the camera so that the Z axis (center vertical in this image) is always aligned with the view direction projected into the XZ plane. The vertex shader would then read terrain heights from a height texture and adjust the Y coordinate of the mesh to match a height field that defines the terrain. This eliminates the need for culling (since the mesh is generated to match the viewport dimensions) and the need to modify the index and/or vertex buffers when drawing the terrain. Obviously this doesn't address terrain with overhangs, etc, but that could be handled to a certain extent by including a second mesh that defines a sort of "ceiling" via a different texture. The other LoD schemes I've seen aren't particularly difficult to implement and, in some cases, are a lot more flexible, but this seemed like a decent quick-and-dirty way to handle height map-based terrain without getting into geometry manipulation. Has anyone tried this? Opinions?

    Read the article

  • Searching integer sequences

    - by David Gibson
    I have a fairly complex search problem that I've managed to reduce to the following description. I've been googling but haven't been able to find an algorithm that seems to fit my problem cleanly. In particular the need to skip arbitrary integers. Maybe someone here can point me to something? Take a sequence of integers A, for example (1 2 3 4) Take various sequences of integers and test if any of them match A such that. A contains all of the integers in the tested sequence The ordering of the integers in the tested sequence are the same in A We don't care about any integers in A that are not in the test sequence We want all matching test sequences, not just the first. An example A = (1 2 3 4) B = (1 3) C = (1 3 4) D = (3 1) E = (1 2 5) B matches A C matches A D does not match A as the ordering is different E does not match A as it contains an integer not in A I hope that this explanation is clear enough. The best I've managed to do is to contruct a tree of the test sequences and iterate over A. The need to be able to skip integers leads to a lot of unsuccessful search paths. Thanks Reading some suggestions I feel that I have to clarify a couple of points that I left too vague. Repeated numbers are allowed, in fact this is quite important as it allows a single test sequence to match A is multiple ways A = (1234356), B = (236), matches could be either -23---6 or -2--3-6 I expect there to be a very large number of test sequences, in the thousands at least and sequence A will tend to have a max length of maybe 20. Thus simply trying to match each test sequence one by one by iterating becomes extremely inefficient. Sorry if this wasn't clear.

    Read the article

  • How does a one-man developer do its games' sounds?

    - by Gustavo Maciel
    Before anything, that's not a "oh, where can I find resources?" question. Well, I've been curious about one thing in the indie games industry. For the development of the game, such tasks like game design, art, sketches, code programming and etc can be easily done by just one person. You can just take up a paper and pencil and you're a game designer. You can just take software like Photoshop or Paint and you're an artist, a scanner and you're a sketcher, a compiler and you're a programmer. For sound it's different. You may tell me: Well, follow the line, take a lot of instruments and record it. But all we know that things don't work this way. I can list up some changes for us: External noises are a big problem, sound effects can't be made with instruments, it can't sound like a recorded and clipped sound. Well I can imagine how they do this in large companies, with such big studios and etc. But to summarise, my question is: What's the best way for a one-man indie to do all its sound? Does he have to synthesize everything? Record and buy some crazy program for editing sounds?

    Read the article

  • SSIS Denali as part of “Enterprise Information Management”

    - by jorg
    When watching the SQL PASS session “What’s Coming Next in SSIS?” of Steve Swartz, the Group Program Manager for the SSIS team, an interesting question came up: Why is SSIS thought of to be BI, when we use it so frequently for other sorts of data problems? The answer of Steve was that he breaks the world of data work into three parts: Process of inputs BI   Enterprise Information Management All the work you have to do when you have a lot of data to make it useful and clean and get it to the right place. This covers master data management, data quality work, data integration and lineage analysis to keep track of where the data came from. All of these are part of Enterprise Information Management. Next, Steve told Microsoft is developing SSIS as part of a large push in all of these areas in the next release of SQL. So SSIS will be, next to a BI tool, part of Enterprise Information Management in the next release of SQL Server. I'm interested in the different ways people use SSIS, I've basically used it for ETL, data migrations and processing inputs. In which ways did you use SSIS?

    Read the article

  • Recommended Method to Watch Amazon Prime using Ubuntu 14.04 LTS

    - by Kurt Sanger
    I realize that Hal is no longer in the Ubuntu Software Center for Ubuntu 14.04 and it is only available from a third party at this time. But I would like to know what Ubuntu's plans are for integrating DRM into Linux? Especially with Amazon's integration into the search tool, one would hope that they would make it easier for their Amazon Prime customers to watch Instant Videos. Is the repository for getting Hal for 13.10 safe for use? What will that break if I install it onto 14.04? Or do we need to find another OS that has DRM built into it? If Hal is okay to add to the OS using a third party repo, then why doesn't Ubuntu Software Center support it too? I imagine that Amazon's contract with the video copyright holders requires that they have some protection on electronically distributed media. I also imagine that getting Amazon to change is much harder than getting a bunch of software engineers to fix Ubuntu. Unless they don't want too. At which point Ubuntu isn't really a complete OS. Very disappointing. In general the ease of use of Ubuntu, the software center, and the large variety of applications was alluring. But breaking DRM wasn't a great idea. Can't wait to see what fails in our next update. Please tell us that there is a plan that is going to work in our future.

    Read the article

  • Choosing Technology To Include In Software Design

    How many of us have been forced to select one technology over another when designing a new system? What factors do we and should we consider? How can we ensure the correct business decision is made? When faced with this type of decision it is important to gather as much information possible regarding each technology being considered as well as the project itself. Additionally, I tend to delay my decision about the technology until it is ultimately necessary to be made. The reason why I tend to delay such an important design decision is due to the fact that as the project progresses requirements and other factors can alter a decision for selecting the best technology for a project. Important factors to consider when making technology decisions: Time to Implement and Maintain Total Cost of Technology (including Implementation and maintenance) Adaptability of Technology Implementation Team’s Skill Sets Complexity of Technology (including Implementation and maintenance) orecasted Return On Investment (ROI) Forecasted Profit on Investment (POI) Of the factors to consider the ROI and POI weigh the heaviest because the take in to consideration the other factors when calculating the profitability and return on investments.For a real world example let us consider developing a web based lead management system for a new company. This system can either be hosted on Microsoft Windows based web server or on a Linux based web server. Important Factors for this Example Implementation Team’s Skill Sets Member 1  Skill Set: Classic ASP, ASP.Net, and MS SQL Server Experience: 10 years Member 2  Skill Set: PHP, MySQL, Photoshop and MS SQL Server Experience: 3 years Member 3  Skill Set: C++, VB6, ASP.Net, and MS SQL Server Experience: 12 years Total Cost of Technology (including Implementation and maintenance) Linux Initial Year: $5,000 (Random Value) Additional Years: $3,000 (Random Value) Windows Initial Year: $10,000 (Random Value) Additional Years: $3,000 (Random Value) Complexity of Technology Linux Large Learning Curve with user driven documentation Estimated learning cost: $30,000 Windows Minimal based on Teams skills with Microsoft based documentation Estimated learning cost: $5,000 ROI Linux Total Cost Initial Total Cost: $35,000 Additional Cost $3,000 per year Windows Total Cost Initial Total Cost: $15,000 Additional Cost $3,000 per year Based on the hypothetical numbers it would make more sense to select windows based web server because the initial investment of the technology is much lower initially compared to the Linux based web server.

    Read the article

  • What can you do to decrease the number of live issues with applications?

    - by User Smith
    First off I have seen this post which is slightly similar to my question. : What can you do to decrease the number of deployment bugs of a live website? Let me layout the situation for you. The team of programmers that I belong to have metrics associated with our code. Over the last several months our errors in our live system have increased by a large amount. We require that our updates to applications be tested by at least one other programmer prior to going live. I personally am completely against this as I think that applications should be tested by end users as end users are much better testers than programmers, I am not against programmers testing, obviously programmers need to test code, but they are most of the times too close to the code. The reason I specify that I think end users should test in our scenario is due to the fact that we don't have business analysts, we just have programmers. I come from a background where BAs took care of all the testing once programmers checked off it was ready to go live. We do have a staging environment in place that is a clone of the live environment that we use to ensure that we don't have issues between development and live environments this does catch some bugs. We don't do end user testing really at all, I should say we don't really have anyone testing our code except programmers, which I think gets us into this mess (Ideally, we would have BAs or QA or professional testers test). We don't have a QA team or anything of that nature. We don't have test cases for our projects that are fully laid out. Ok, I am just a peon programmer at the bottom of the rung, but I am probably more tired of these issues than the managers complaining about them. So, I don't have the ability to tell them you are doing it all wrong.....I have tried gentle pushes in the correct direction. Any advice or suggestions on how to alleviate this issue is greatly appreciated. Thanks.

    Read the article

  • Solving Big Problems with Oracle R Enterprise, Part I

    - by dbayard
    Abstract: This blog post will show how we used Oracle R Enterprise to tackle a customer’s big calculation problem across a big data set. Overview: Databases are great for managing large amounts of data in a central place with rigorous enterprise-level controls.  R is great for doing advanced computations.  Sometimes you need to do advanced computations on large amounts of data, subject to rigorous enterprise-level concerns.  This blog post shows how Oracle R Enterprise enables R plus the Oracle Database enabled us to do some pretty sophisticated calculations across 1 million accounts (each with many detailed records) in minutes. The problem: A financial services customer of mine has a need to calculate the historical internal rate of return (IRR) for its customers’ portfolios.  This information is needed for customer statements and the online web application.  In the past, they had solved this with a home-grown application that pulled trade and account data out of their data warehouse and ran the calculations.  But this home-grown application was not able to do this fast enough, plus it was a challenge for them to write and maintain the code that did the IRR calculation. IRR – a problem that R is good at solving: Internal Rate of Return is an interesting calculation in that in most real-world scenarios it is impractical to calculate exactly.  Rather, IRR is a calculation where approximation techniques need to be used.  In this blog post, we will discuss calculating the “money weighted rate of return” but in the actual customer proof of concept we used R to calculate both money weighted rate of returns and time weighted rate of returns.  You can learn more about the money weighted rate of returns here: http://www.wikinvest.com/wiki/Money-weighted_return First Steps- Calculating IRR in R We will start with calculating the IRR in standalone/desktop R.  In our second post, we will show how to take this desktop R function, deploy it to an Oracle Database, and make it work at real-world scale.  The first step we did was to get some sample data.  For a historical IRR calculation, you have a balances and cash flows.  In our case, the customer provided us with several accounts worth of sample data in Microsoft Excel.      The above figure shows part of the spreadsheet of sample data.  The data provides balances and cash flows for a sample account (BMV=beginning market value. FLOW=cash flow in/out of account. EMV=ending market value). Once we had the sample spreadsheet, the next step we did was to read the Excel data into R.  This is something that R does well.  R offers multiple ways to work with spreadsheet data.  For instance, one could save the spreadsheet as a .csv file.  In our case, the customer provided a spreadsheet file containing multiple sheets where each sheet provided data for a different sample account.  To handle this easily, we took advantage of the RODBC package which allowed us to read the Excel data sheet-by-sheet without having to create individual .csv files.  We wrote ourselves a little helper function called getsheet() around the RODBC package.  Then we loaded all of the sample accounts into a data.frame called SimpleMWRRData. Writing the IRR function At this point, it was time to write the money weighted rate of return (MWRR) function itself.  The definition of MWRR is easily found on the internet or if you are old school you can look in an investment performance text book.  In the customer proof, we based our calculations off the ones defined in the The Handbook of Investment Performance: A User’s Guide by David Spaulding since this is the reference book used by the customer.  (One of the nice things we found during the course of this proof-of-concept is that by using R to write our IRR functions we could easily incorporate the specific variations and business rules of the customer into the calculation.) The key thing with calculating IRR is the need to solve a complex equation with a numerical approximation technique.  For IRR, you need to find the value of the rate of return (r) that sets the Net Present Value of all the flows in and out of the account to zero.  With R, we solve this by defining our NPV function: where bmv is the beginning market value, cf is a vector of cash flows, t is a vector of time (relative to the beginning), emv is the ending market value, and tend is the ending time. Since solving for r is a one-dimensional optimization problem, we decided to take advantage of R’s optimize method (http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html). The optimize method can be used to find a minimum or maximum; to find the value of r where our npv function is closest to zero, we wrapped our npv function inside the abs function and asked optimize to find the minimum.  Here is an example of using optimize: where low and high are scalars that indicate the range to search for an answer.   To test this out, we need to set values for bmv, cf, t, emv, tend, low, and high.  We will set low and high to some reasonable defaults. For example, this account had a negative 2.2% money weighted rate of return. Enhancing and Packaging the IRR function With numerical approximation methods like optimize, sometimes you will not be able to find an answer with your initial set of inputs.  To account for this, our approach was to first try to find an answer for r within a narrow range, then if we did not find an answer, try calling optimize() again with a broader range.  See the R help page on optimize()  for more details about the search range and its algorithm. At this point, we can now write a simplified version of our MWRR function.  (Our real-world version is  more sophisticated in that it calculates rate of returns for 5 different time periods [since inception, last quarter, year-to-date, last year, year before last year] in a single invocation.  In our actual customer proof, we also defined time-weighted rate of return calculations.  The beauty of R is that it was very easy to add these enhancements and additional calculations to our IRR package.)To simplify code deployment, we then created a new package of our IRR functions and sample data.  For this blog post, we only need to include our SimpleMWRR function and our SimpleMWRRData sample data.  We created the shell of the package by calling: To turn this package skeleton into something usable, at a minimum you need to edit the SimpleMWRR.Rd and SimpleMWRRData.Rd files in the \man subdirectory.  In those files, you need to at least provide a value for the “title” section. Once that is done, you can change directory to the IRR directory and type at the command-line: The myIRR package for this blog post (which has both SimpleMWRR source and SimpleMWRRData sample data) is downloadable from here: myIRR package Testing the myIRR package Here is an example of testing our IRR function once it was converted to an installable package: Calculating IRR for All the Accounts So far, we have shown how to calculate IRR for a single account.  The real-world issue is how do you calculate IRR for all of the accounts?This is the kind of situation where we can leverage the “Split-Apply-Combine” approach (see http://www.cscs.umich.edu/~crshalizi/weblog/815.html).  Given that our sample data can fit in memory, one easy approach is to use R’s “by” function.  (Other approaches to Split-Apply-Combine such as plyr can also be used.  See http://4dpiecharts.com/2011/12/16/a-quick-primer-on-split-apply-combine-problems/). Here is an example showing the use of “by” to calculate the money weighted rate of return for each account in our sample data set.  Recap and Next Steps At this point, you’ve seen the power of R being used to calculate IRR.  There were several good things: R could easily work with the spreadsheets of sample data we were given R’s optimize() function provided a nice way to solve for IRR- it was both fast and allowed us to avoid having to code our own iterative approximation algorithm R was a convenient language to express the customer-specific variations, business-rules, and exceptions that often occur in real-world calculations- these could be easily added to our IRR functions The Split-Apply-Combine technique can be used to perform calculations of IRR for multiple accounts at once. However, there are several challenges yet to be conquered at this point in our story: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In our next blog post in this series, we will show you how Oracle R Enterprise solved these challenges.

    Read the article

  • Silverlight Cream Top Posted Authors August, 2010 to January, 2011

    - by Dave Campbell
    It's *way* past the first of February, and it's now time to recognize devs that have a large number of posts in Silverlight Cream. Ground Rules I pick what posts are on the blog Only posts that go in the database are included The author has to appear in SC at least 4 of the 6 months considered I averaged the monthly posts and am only showing Authors with an average greater than 1. Here are the Top Posted Authors at Silverlight Cream for August 1, 2010 through January 31, 2011: It is my intention to post a new list sometime shortly after the 1st of every month to recognize the top posted in the previous 6 months, so next up is March 1! Some other metrics for Silverlight Cream: At the time of this posting there are 7304 articles aggregated and searchable by partial Author, partial Title, keywords (in the synopsis), or partial URL. There are also 118 tags by which the articles can be searched. This is an increase of 265 posts over last month. At the time of this posting there are 783 articles tagged wp7dev. This is an increase of 155 posts over last month, or over half of the posts added. Stay in the 'Light!

    Read the article

  • links for 2011-03-01

    - by Bob Rhubart
    Oracle Technology Network Architect Day: Denver - March 23 This live one-day event will bring together architects from a broad range of disciplines and domains to share insights and expertise in the use of Oracle technologies to meet the challenges today’s architects regularly face. (tags: oracle otn architect entarch) Java.net Reborn (Oracle Technology Network Blog (aka TechBlog)) "The migration was huge effort. Over 1400 projects were migrated (and some 30 projects are left to go). A large part of the migration was a big cleanup of abandoned projects...The new java.net site is smaller, faster and now the percentage of good, current content is much higher." (tags: oracle otn java java.net) This Week: OTN Java Developer Day in Boston, Massachusetts (US) | Java.net "This Thursday, March 3, the Oracle Technology Network will be hosting an OTN Developer Day titled You are the future of Java in Boston, Massachusetts (US). The all-day event includes a keynote address ("Java, the Language of the Future") and four separate tracks..." (tags: oracle otn java event) A brief introduction to BRM and architecture (Red Adventure) Yani Miguel offers a primer on the architecture behind Billing and Revenue Management. (tags: oracle otn brm) SOA Suite Integration: Part 1: Building a Web Service (The Shorten Spot) Anthony Shorten's first post in a new series "will not feature SOA Suite at all, but will concentrate on the capability for the Oracle Utilities Application Framework to create Web Services you can use for integration." (tags: oracle otn SOA soasuite) Darwin-IT: VirtualBox on Windows XP Martien van den Akker shares a few tips. (tags: oracle otn virtualization virtualbox) Pas Apicella: Developing RESTful Web Services from JDeveloper 11g (11.1.1.4) Plas says: "In this example we use JDeveloper to create a basic JAX-RS Web Service from support provided within the code editor as no wizard support exists within JDeveloper 11g at this stage." (tags: oracle otn REST SOA) Alexander Buckley: Maintenance Review of the Java VM Specification The Java Virtual Machine Specification is the authoritative reference for the design of the Java virtual machine that underpins the Java SE platform. In an implementation-independent manner, the Specification describes the architecture, linking model, and instruction set of the Java virtual machine, (tags: oracle otn java virtualization jvm javase)

    Read the article

  • Avoiding Object Oriented Pitfalls, Migrating from C, What Worked for You?

    - by Stephen
    I've been programming in procedural languages for quite some time now, and my first reaction to a problem is to start breaking it down into tasks to perform rather than to consider the different entities (objects) that exist and their relationships. I have had a university course in OOP, and understand the fundamentals of encapsulation, data abstraction, polymorphism, modularity and inheritance. I read Learning to think in the Object Oriented Way and Learning object oriented thinking, and will be looking at some of the books pointed to in those answers. I think that several of my medium to large sized projects will benefit from effective use of OOP but as a novice I would like to avoid time consuming, common errors. Based on your experiences, what are these pitfalls and what are reasonable ways around them? If you could explain why they are pitfalls, and how your suggestion is effective in addressing the issue it'd be appreciated. I'm thinking along the lines of something like "Is it common to have a fair number of observer and modifier methods and use private variables or are there techniques for consolidating/reducing them?" I'm not worried about using C++ as a pure OO language, if there are good reasons to mix methods. (Reminiscent of the reasons to use GOTOs, albeit sparingly.) Thank you!

    Read the article

  • Release/Change management - best aproach

    - by Bob Rivers
    I asked this question an year ago in StackOverflow and never got a good answer. Since Programmers seems to be a better place to ask it, I'll give it a try... What is the better way to work with release management? More specifically what would be the best way to release packages? For example, assuming that you have a relatively stable system, a good quality assurance process (QA), etc. How do you prefer to release new versions? Let's assume that we are talking about a mid to large "centralized" web system (no clients), in-house development. This system can be considered "vital" for a corporate operations. I have a tendency to prefer to do this by releasing packets at regular intervals, not greater than 1 to 3 months. During this period, I will include into the package,fixes and improvements and make the implementation in production environment only once. But I've seen some people who prefer to place small changes in production, but with a greater frequency. The claim of these people is that by doing so, it is easier to identify bugs that have gone through the process of QA: in a package with 10 changes and another with only 1, it is much easier to know what caused the problem in the package with just one change... What is the opinion came from you?

    Read the article

  • Creating an expandable, cross-platform compatible program "core".

    - by Thomas Clayson
    Hi there. Basically the brief is relatively simple. We need to create a program core. An engine that will power all sorts of programs with a large number of distinct potential applications and deployments. The core will be an analytics and algorithmic processor which will essentially take user-specific input and output scenarios based on the information it gets, whilst recording this information for reporting. It needs to be cross platform compatible. Something that can have platform specific layers put on top which can interface with the core. It also needs to be able to be expandable, for instance, modular with developers being able to write "add-ons" or "extensions" which can alter the function of the end program and can use the core to its full extent. (For instance, a good example of what I'm looking to create is a browser. It has its main core, the web-kit engine, for instance, and then on top of this is has a platform-specific GUI and can also have add-ons and extensions which can change the behavior of the program.) Our problem is that the extensions need to interface directly with the main core and expand/alter that functionality rather than the platform specific "layer". So, given that I have no experience in this whatsoever (I have a PHP background and recently objective-c), where should I start, and is there any knowledge/wisdom you can impart on me please? Thanks for all the help and advice you can give me. :) If you need any more explanation just ask. At the moment its in the very early stages of development, so we're just researching all possible routes of development. Thanks a lot

    Read the article

  • How to indicate reliability when reporting availability of competencies

    - by Jan Doggen
    We have employees with competencies: Pete Welder Carpenter Melissa Carpenter Assume they both work 40 hours/week, and have not yet been assigned work. We need to report the availability of these competencies, expressed in hours. As far as I can see now, we can report this in two ways: Method A. When someone has multiple competencies, count them both. Welder 40 hours Carpenter 80 hours Method B. When someone has multiple competencies, count an equal division of hours for each Welder 20 hours Carpenter 60 hours Method A has our preference: - A good planner will know to plan the least available competency first. If 30 hours of welding is planned, we will be left with 10 welder, 50 carpenter. - Method B has the disadvantage that the planner thinks he cannot plan the job when 30 hours of welding is required. However, if we report this we would like to give an estimate of the reliability of the numbers for each competency, i.e. how much are these over-reported? In my example A, would I say that carpenter is 100% over-reported, or 50%, or maybe another number? How would I calculate this for large numbers of competencies? I'm sure we are not the first ones dealing with this, is there a 'usual' way of doing this in planning? Additionally: - Would there be an even better method than A or B? - Optionally, we also have an preference order of competencies (like: use him/her in this order), Pete could be 1. welder 2. carpenter. Does this introduce new options?

    Read the article

  • ASP.NET Session Management

    - by geekrutherford
    Great article (a little old but still relevant) about the inner workings of session management in ASP.NET: Underpinnings of the Session State Management Implementation in ASP.NET.   Using StateServer and the BinaryFormatter serialization occuring caused me quite the headache over the last few days. Curiously, it appears the w3wp.exe process actually consumes more memory when utilizing StateServer and storing somewhat large and complex data types in session.   Users began experiencing Out Of Memory exceptions in the production environment. Looking at the stack trace it related to serialization using the BinaryFormatter. Using remote debugging against our QA server I noted that the code in the application functioned without issue. The exception occured outside the context of the application itself when the request had completed and the web server was trying to serialize session state into the StateServer.   The short term solution is switching back to the InProc method. Thus far this has proven to consume considerably less memory and has caused no issues. Long term the complex object stored in session will be off-loaded into a web service used to access the information directly from the database outside the context of the object used to encapsulate it.

    Read the article

  • PHP file_put_contents File Locking

    - by hozza
    The Senario: You have a file with a string (average sentence worth) on each line. For arguments sake lets say this file is 1Mb in size (thousands of lines). You have a script that reads the file, changes some of the strings within the document (not just appending but also removing and modifying some lines) and then overwrites all the data with the new data. The Questions: Does 'the server' PHP, OS or httpd etc. already have systems in place to stop issues like this (reading/writing half way through a write)? i. If it does, please explain how it works and give examples or links to relevant documentation. ii. If not, are there things I can enable or set-up, such as locking a file until a write is completed and making all other reads and/or writes fail until the previous script has finished writing? My Assumptions and Other Information: The server in question is running PHP and Apache or Lighttpd. If the script is called by one user and is halfway through writing to the file and another user reads the file at that exact moment. The user who reads it will not get the full document, as it hasn't been written yet. (If this assumption is wrong please correct me) I'm only concerned with PHP writing and reading to a text file, and in particular, the functions "fopen"/"fwrite" and mainly "file_put_contents". I have looked at the "file_put_contents" documentation but have not found the level of detail or a good explanation of what the "LOCK_EX" flag is or does. The senario is an EXAMPLE of a worst case senario where I would assume these issues are more likely to occur, due to the large size of the file and the way the data is edited. I want to learn more about these issues and don't want or need answers or comments such as "use mysql" or "why are you doing that" because I'm not doing that, I just want to learn about file read/writing with PHP and don't seem to be looking in the right places/documentation and yes I understand PHP is not the perfect language for working with files in this way...

    Read the article

< Previous Page | 216 217 218 219 220 221 222 223 224 225 226 227  | Next Page >