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• Advanced Data Source Engine coming to Telerik Reporting Q1 2010

  This is the final blog post from the pre-release series. In it we are going to share with you some of the updates coming to our reporting solution in Q1 2010. A new Declarative Data Source Engine will be added to Telerik Reporting, that will allow full control over data management, and deliver significant gains in rendering performance and memory consumption. Some of the engines new features will be: Data source parameters - those parameters will be used to limit data retrieved from the data source to just the data needed for the report. Data source parameters are processed on the data source side, however only queried data is fetched to the reporting engine, rather than the full data source. This leads to lower memory consumption, because data operations are performed on queried data only, rather than on all data. As a result, only the queried data needs to be stored in the memory vs. the whole dataset, which was the case with the old approach Support for stored procedures - they will assist in achieving a consistent implementation of logic across applications, and are especially practical for performing repetitive tasks. A stored procedure stores the SQL statements and logic, which can then be executed in different reports and/or applications. Stored Procedures will not only save development time, but they will also improve performance, because each stored procedure is compiled on the data base server once, and then is reutilized. In Telerik Reporting, the stored procedure will also be parameterized, where elements of the SQL statement will be bound to parameters. These parameterized SQL queries will be handled through the data source parameters, and are evaluated at run time. Using parameterized SQL queries will improve the performance and decrease the memory footprint of your application, because they will be applied directly on the database server and only the necessary data will be downloaded on the middle tier or client machine; Calculated fields through expressions - with the help of the new reporting engine you will be able to use field values in formulas to come up with a calculated field. A calculated field is a user defined field that is computed "on the fly" and does not exist in the data source, but can perform calculations using the data of the data source object it belongs to. Calculated fields are very handy for adding frequently used formulas to your reports; Improved performance and optimized in-memory OLAP engine - the new data source will come with several improvements in how aggregates are calculated, and memory is managed. As a result, you may experience between 30% (for simpler reports) and 400% (for calculation-intensive reports) in rendering performance, and about 50% decrease in memory consumption. Full design time support through wizards - Declarative data sources are a great advance and will save developers countless hours of coding. In Q1 2010, and true to Telerik Reportings essence, using the new data source engine and its features requires little to no coding, because we have extended most of the wizards to support the new functionality. The newly extended wizards are available in VS2005/VS2008/VS2010 design-time. More features will be revealed on the product's what's new page when the new version is officially released in a few days. Also make sure you attend the free webinar on Thursday, March 11th that will be dedicated to the updates in Telerik Reporting Q1 2010. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Pie Charts Just Don't Work When Comparing Data - Number 10 of Top 10 Reasons to Never Ever Use a Pie

  - by Tony Wolfram

  When comparing data, which is what a pie chart is for, people have a hard time judging the angles and areas of the multiple pie slices in order to calculate how much bigger one slice is than the others. Pie Charts Don't Work A slice of pie is good for serving up a portion of desert. It's not good for making a judgement about how big the slice is, what percentage of 100 it is, or how it compares to other slices. People have trouble comparing angles and areas to each other. Controlled studies show that people will overestimate the percentage that a pie slice area represents. This is because we have trouble calculating the area based on the space between the two angles that define the slice. This picture shows how a pie chart is useless in determing the largest value when you have to compare pie slices.   You can't compare angles and slice areas to each other. Human perception and cognition is poor when viewing angles and areas and trying to make a mental comparison. Pie charts overload the working memory, forcing the person to make complicated calculations, and at the same time make a decision based on those comparisons. What's the point of showing a pie chart when you want to compare data, except to say, "well, the slices are almost the same, but I'm not really sure which one is bigger, or by how much, or what order they are from largest to smallest. But the colors sure are pretty. Plus, I like round things. Oh,was I suppose to make some important business decision? Sorry." Bad Choices and Bad Decisions Interaction Designers, Graphic Artists, Report Builders, Software Developers, and Executives have all made the decision to use pie charts in their reports, software applications, and dashboards. It was a bad decision. It was a poor choice. There are always better options and choices, yet the designer still made the decision to use a pie chart. I'll expore why people make such poor choices in my upcoming blog entires. (Hint: It has more to do with emotions than with analytical thinking.) I've outlined my opinions and arguments about the evils of using pie charts in "Countdown of Top 10 Reasons to Never Ever Use a Pie Chart." Each of my next 10 blog entries will support these arguments with illustrations, examples, and references to studies. But my goal is not to continuously and endlessly rage against the evils of using pie charts. This blog is not about pie charts. This blog is about understanding why designers choose to use a pie chart. Why, when give better alternatives, and acknowledging the shortcomings of pie charts, do designers over and over again still freely choose to place a pie chart in a report? As an extra treat and parting shot, check out the nice pie chart that Wikipedia uses to illustrate the United States population by state.   Remember, somebody chose to use this pie chart, with all its glorious colors, and post it on Wikipedia for all the world to see. My next blog will give you a better alternative for displaying comparable data - the sorted bar chart.

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• From NaN to Infinity...and Beyond!

  - by Tony Davis

  It is hard to believe that it was once possible to corrupt a SQL Server Database by storing perfectly normal data values into a table; but it is true. In SQL Server 2000 and before, one could inadvertently load invalid data values into certain data types via RPC calls or bulk insert methods rather than DML. In the particular case of the FLOAT data type, this meant that common 'special values' for this type, namely NaN (not-a-number) and +/- infinity, could be quite happily plugged into the database from an application and stored as 'out-of-range' values. This was like a time-bomb. When one then tried to query this data; the values were unsupported and so data pages containing them were flagged as being corrupt. Any query that needed to read a column containing the special value could fail or return unpredictable results. Microsoft even had to issue a hotfix to deal with failures in the automatic recovery process, caused by the presence of these NaN values, which rendered the whole database inaccessible! This problem is history for those of us on more current versions of SQL Server, but its ghost still haunts us. Recently, for example, a developer on Red Gate’s SQL Response team reported a strange problem when attempting to load historical monitoring data into a SQL Server 2005 database via the C# ADO.NET provider. The ratios used in some of their reporting calculations occasionally threw out NaN or infinity values, and the subsequent attempts to load these values resulted in a nasty error. It turns out to be a different manifestation of the same problem. SQL Server 2005 still does not fully support the IEEE 754 standard for floating point numbers, in that the FLOAT data type still cannot handle NaN or infinity values. Instead, they just added validation checks that prevent the 'invalid' values from being loaded in the first place. For people migrating from SQL Server 2000 databases that contained out-of-range FLOAT (or DATETIME etc.) data, to SQL Server 2005, Microsoft have added to the latter's version of the DBCC CHECKDB (or CHECKTABLE) command a DATA_PURITY clause. When enabled, this will seek out the corrupt data, but won’t fix it. You have to do this yourself in what can often be a slow, painful manual process. Our development team, after a quizzical shrug of the shoulders, simply decided to represent NaN and infinity values as NULL, and move on, accepting the minor inconvenience of not being able to tell them apart. However, what of scientific, engineering and other applications that really would like the luxury of being able to both store and access these perfectly-reasonable floating point data values? The sticking point seems to be the stipulation in the IEEE 754 standard that, when NaN is compared to any other value including itself, the answer is "unequal" (i.e. FALSE). This is clearly different from normal number comparisons and has repercussions for such things as indexing operations. Even so, this hardly applies to infinity values, which are single definite values. In fact, there is some encouraging talk in the Connect note on this issue that they might be supported 'in the SQL Server 2008 timeframe'. If didn't happen; SQL 2008 doesn't support NaN or infinity values, though one could be forgiven for thinking otherwise, based on the MSDN documentation for the FLOAT type, which states that "The behavior of float and real follows the IEEE 754 specification on approximate numeric data types". However, the truth is revealed in the XPath documentation, which states that "…float (53) is not exactly IEEE 754. For example, neither NaN (Not-a-Number) nor infinity is used…". Is it really so hard to fix this problem the right way, and properly support in SQL Server the IEEE 754 standard for the floating point data type, NaNs, infinities and all? Oracle seems to have managed it quite nicely with its BINARY_FLOAT and BINARY_DOUBLE types, so it is technically possible. We have an enterprise-class database that is marketed as being part of an 'integrated' Windows platform. Absurdly, we have .NET and XPath libraries that fully support the standard for floating point numbers, and we can't even properly store these values, let alone query them, in the SQL Server database! Cheers, Tony.

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• LINQ and ordering of the result set

  - by vik20000in

  After filtering and retrieving the records most of the time (if not always) we have to sort the record in certain order. The sort order is very important for displaying records or major calculations. In LINQ for sorting data the order keyword is used. With the help of the order keyword we can decide on the ordering of the result set that is retrieved after the query.  Below is an simple example of the order keyword in LINQ.     string[] words = { "cherry", "apple", "blueberry" };     var sortedWords =         from word in words         orderby word         select word; Here we are ordering the data retrieved based on the string ordering. If required the order can also be made on any of the property of the individual like the length of the string.     var sortedWords =         from word in words         orderby word.Length         select word; You can also make the order descending or ascending by adding the keyword after the parameter.     var sortedWords =         from word in words         orderby word descending         select word; But the best part of the order clause is that instead of just passing a field you can also pass the order clause an instance of any class that implements IComparer interface. The IComparer interface holds a method Compare that Has to be implemented. In that method we can write any logic whatsoever for the comparision. In the below example we are making a string comparison by ignoring the case. string[] words = { "aPPLE", "AbAcUs", "bRaNcH", "BlUeBeRrY", "cHeRry"}; var sortedWords = words.OrderBy(a => a, new CaseInsensitiveComparer());  public class CaseInsensitiveComparer : IComparer<string> {     public int Compare(string x, string y)     {         return string.Compare(x, y, StringComparison.OrdinalIgnoreCase);     } }  But while sorting the data many a times we want to provide more than one sort so that data is sorted based on more than one condition. This can be achieved by proving the next order followed by a comma.     var sortedWords =         from word in words         orderby word , word.length         select word; We can also use the reverse() method to reverse the full order of the result set.     var sortedWords =         from word in words         select word.Reverse();                                 Vikram

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• HPCM 11.1.2.x - Outline Optimisation for Calculation Performance

  - by Jane Story

  When an HPCM application is first created, it is likely that you will want to carry out some optimisation on the HPCM application’s Essbase outline in order to improve calculation execution times. There are several things that you may wish to consider. Because at least one dense dimension for an application is required to deploy from HPCM to Essbase, “Measures” and “AllocationType”, as the only required dimensions in an HPCM application, are created dense by default. However, for optimisation reasons, you may wish to consider changing this default dense/sparse configuration. In general, calculation scripts in HPCM execute best when they are targeting destinations with one or more dense dimensions. Therefore, consider your largest target stage i.e. the stage with the most assignment destinations and choose that as a dense dimension. When optimising an outline in this way, it is not possible to have a dense dimension in every target stage and so testing with the dense/sparse settings in every stage is the key to finding the best configuration for each individual application. It is not possible to change the dense/sparse setting of individual cloned dimensions from EPMA. When a dimension that is to be repeated in multiple stages, and therefore cloned, is defined in EPMA, every instance of that dimension has the same storage setting. However, such manual changes may not be preserved in all cases. Please see below for full explanation. However, once the application has been deployed from EPMA to HPCM and from HPCM to Essbase, it is possible to make the dense/sparse changes to a cloned dimension directly in Essbase. This can be done by editing the properties of the outline in Essbase Administration Services (EAS) and manually changing the dense/sparse settings of individual dimensions. There are two methods of deployment from HPCM to Essbase from 11.1.2.1. There is a “replace” deploy method and an “update” deploy method: “Replace” will delete the Essbase application and replace it. If this method is chosen, then any changes made directly on the Essbase outline will be lost. If you use the update deploy method (with or without archiving and reloading data), then the Essbase outline, including any manual changes you have made (i.e. changes to dense/sparse settings of the cloned dimensions), will be preserved. Notes If you are using the calculation optimisation technique mentioned in a previous blog to calculate multiple POVs (https://blogs.oracle.com/pa/entry/hpcm_11_1_2_optimising) and you are calculating all members of that POV dimension (e.g. all months in the Period dimension) then you could consider making that dimension dense. Always review Block sizes after all changes! The maximum block size recommended in the Essbase Database Administrator’s Guide is 100k for 32 bit Essbase and 200k for 64 bit Essbase. However, calculations may perform better with a larger than recommended block size provided that sufficient memory is available on the Essbase server. Test different configurations to determine the most optimal solution for your HPCM application. Please note that this blog article covers HPCM outline optimisation only. Additional performance tuning can be achieved by methodically testing database settings i.e data cache, index cache and/or commit block settings. For more information on Essbase tuning best practices, please review these items in the Essbase Database Administrators Guide. For additional information on the commit block setting, please see the previous PA blog article https://blogs.oracle.com/pa/entry/essbase_11_1_2_commit

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• Speeding up procedural texture generation

  - by FalconNL

  Recently I've begun working on a game that takes place in a procedurally generated solar system. After a bit of a learning curve (having neither worked with Scala, OpenGL 2 ES or Libgdx before), I have a basic tech demo going where you spin around a single procedurally textured planet: The problem I'm running into is the performance of the texture generation. A quick overview of what I'm doing: a planet is a cube that has been deformed to a sphere. To each side, a n x n (e.g. 256 x 256) texture is applied, which are bundled in one 8n x n texture that is sent to the fragment shader. The last two spaces are not used, they're only there to make sure the width is a power of 2. The texture is currently generated on the CPU, using the updated 2012 version of the simplex noise algorithm linked to in the paper 'Simplex noise demystified'. The scene I'm using to test the algorithm contains two spheres: the planet and the background. Both use a greyscale texture consisting of six octaves of 3D simplex noise, so for example if we choose 128x128 as the texture size there are 128 x 128 x 6 x 2 x 6 = about 1.2 million calls to the noise function. The closest you will get to the planet is about what's shown in the screenshot and since the game's target resolution is 1280x720 that means I'd prefer to use 512x512 textures. Combine that with the fact the actual textures will of course be more complicated than basic noise (There will be a day and night texture, blended in the fragment shader based on sunlight, and a specular mask. I need noise for continents, terrain color variation, clouds, city lights, etc.) and we're looking at something like 512 x 512 x 6 x 3 x 15 = 70 million noise calls for the planet alone. In the final game, there will be activities when traveling between planets, so a wait of 5 or 10 seconds, possibly 20, would be acceptable since I can calculate the texture in the background while traveling, though obviously the faster the better. Getting back to our test scene, performance on my PC isn't too terrible, though still too slow considering the final result is going to be about 60 times worse: 128x128 : 0.1s 256x256 : 0.4s 512x512 : 1.7s This is after I moved all performance-critical code to Java, since trying to do so in Scala was a lot worse. Running this on my phone (a Samsung Galaxy S3), however, produces a more problematic result: 128x128 : 2s 256x256 : 7s 512x512 : 29s Already far too long, and that's not even factoring in the fact that it'll be minutes instead of seconds in the final version. Clearly something needs to be done. Personally, I see a few potential avenues, though I'm not particularly keen on any of them yet: Don't precalculate the textures, but let the fragment shader calculate everything. Probably not feasible, because at one point I had the background as a fullscreen quad with a pixel shader and I got about 1 fps on my phone. Use the GPU to render the texture once, store it and use the stored texture from then on. Upside: might be faster than doing it on the CPU since the GPU is supposed to be faster at floating point calculations. Downside: effects that cannot (easily) be expressed as functions of simplex noise (e.g. gas planet vortices, moon craters, etc.) are a lot more difficult to code in GLSL than in Scala/Java. Calculate a large amount of noise textures and ship them with the application. I'd like to avoid this if at all possible. Lower the resolution. Buys me a 4x performance gain, which isn't really enough plus I lose a lot of quality. Find a faster noise algorithm. If anyone has one I'm all ears, but simplex is already supposed to be faster than perlin. Adopt a pixel art style, allowing for lower resolution textures and fewer noise octaves. While I originally envisioned the game in this style, I've come to prefer the realistic approach. I'm doing something wrong and the performance should already be one or two orders of magnitude better. If this is the case, please let me know. If anyone has any suggestions, tips, workarounds, or other comments regarding this problem I'd love to hear them.

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• Skewed: a rotating camera in a simple CPU-based voxel raycaster/raytracer

  - by voxelizr

  TL;DR -- in my first simple software voxel raycaster, I cannot get camera rotations to work, seemingly correct matrices notwithstanding. The result is skewed: like a flat rendering, correctly rotated, however distorted and without depth. (While axis-aligned ie. unrotated, depth and parallax are as expected.) I'm trying to write a simple voxel raycaster as a learning exercise. This is purely CPU based for now until I figure out how things work exactly -- fow now, OpenGL is just (ab)used to blit the generated bitmap to the screen as often as possible. Now I have gotten to the point where a perspective-projection camera can move through the world and I can render (mostly, minus some artifacts that need investigation) perspective-correct 3-dimensional views of the "world", which is basically empty but contains a voxel cube of the Stanford Bunny. So I have a camera that I can move up and down, strafe left and right and "walk forward/backward" -- all axis-aligned so far, no camera rotations. Herein lies my problem. Screenshot #1: correct depth when the camera is still strictly axis-aligned, ie. un-rotated. Now I have for a few days been trying to get rotation to work. The basic logic and theory behind matrices and 3D rotations, in theory, is very clear to me. Yet I have only ever achieved a "2.5 rendering" when the camera rotates... fish-eyey, bit like in Google Streetview: even though I have a volumetric world representation, it seems --no matter what I try-- like I would first create a rendering from the "front view", then rotate that flat rendering according to camera rotation. Needless to say, I'm by now aware that rotating rays is not particularly necessary and error-prone. Still, in my most recent setup, with the most simplified raycast ray-position-and-direction algorithm possible, my rotation still produces the same fish-eyey flat-render-rotated style looks: Screenshot #2: camera "rotated to the right by 39 degrees" -- note how the blue-shaded left-hand side of the cube from screen #2 is not visible in this rotation, yet by now "it really should"! Now of course I'm aware of this: in a simple axis-aligned-no-rotation-setup like I had in the beginning, the ray simply traverses in small steps the positive z-direction, diverging to the left or right and top or bottom only depending on pixel position and projection matrix. As I "rotate the camera to the right or left" -- ie I rotate it around the Y-axis -- those very steps should be simply transformed by the proper rotation matrix, right? So for forward-traversal the Z-step gets a bit smaller the more the cam rotates, offset by an "increase" in the X-step. Yet for the pixel-position-based horizontal+vertical-divergence, increasing fractions of the x-step need to be "added" to the z-step. Somehow, none of my many matrices that I experimented with, nor my experiments with matrix-less hardcoded verbose sin/cos calculations really get this part right. Here's my basic per-ray pre-traversal algorithm -- syntax in Go, but take it as pseudocode: fx and fy: pixel positions x and y rayPos: vec3 for the ray starting position in world-space (calculated as below) rayDir: vec3 for the xyz-steps to be added to rayPos in each step during ray traversal rayStep: a temporary vec3 camPos: vec3 for the camera position in world space camRad: vec3 for camera rotation in radians pmat: typical perspective projection matrix The algorithm / pseudocode: // 1: rayPos is for now "this pixel, as a vector on the view plane in 3d, at The Origin" rayPos.X, rayPos.Y, rayPos.Z = ((fx / width) - 0.5), ((fy / height) - 0.5), 0 // 2: rotate around Y axis depending on cam rotation. No prob since view plane still at Origin 0,0,0 rayPos.MultMat(num.NewDmat4RotationY(camRad.Y)) // 3: a temp vec3. planeDist is -0.15 or some such -- fov-based dist of view plane from eye and also the non-normalized, "in axis-aligned world" traversal step size "forward into the screen" rayStep.X, rayStep.Y, rayStep.Z = 0, 0, planeDist // 4: rotate this too -- 0,zstep should become some meaningful xzstep,xzstep rayStep.MultMat(num.NewDmat4RotationY(CamRad.Y)) // set up direction vector from still-origin-based-ray-position-off-rotated-view-plane plus rotated-zstep-vector rayDir.X, rayDir.Y, rayDir.Z = -rayPos.X - me.rayStep.X, -rayPos.Y, rayPos.Z + rayStep.Z // perspective projection rayDir.Normalize() rayDir.MultMat(pmat) // before traversal, the ray starting position has to be transformed from origin-relative to campos-relative rayPos.Add(camPos) I'm skipping the traversal and sampling parts -- as per screens #1 through #3, those are "basically mostly correct" (though not pretty) -- when axis-aligned / unrotated.

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• 5 Ways to Determine Mobile Location

  - by David Dorf

  In my previous post, I mentioned the importance of determining the location of a consumer using their mobile phone.  Retailers can track anonymous mobile phones to determine traffic patterns both inside and outside their stores.  And with consumers' permission, retailers can send location-aware offers to mobile phones; for example, a coupon for cereal as you walk down that aisle.  When paying with Square, your location is matched with the transaction.  So there are lots of reasons for retailers to want to know the location of their customers.  But how is it done? I thought I'd dive a little deeper on that topic and consider the approaches to determining location. 1. Tower Triangulation By comparing the relative signal strength from multiple antenna towers, a general location of a phone can be roughly determined to an accuracy of 200-1000 meters.  The more towers involved, the more accurate the location. 2. GPS Using Global Positioning Satellites is more accurate than using cell towers, but it takes longer to find the satellites, it uses more battery, and it won't well indoors.  For geo-fencing applications, like those provided by Placecast and Digby, cell towers are often used to determine if the consumer is nearing a "fence" then switches to GPS to determine the actual crossing of the fence. 3. WiFi Triangulation WiFi triangulation is usually more accurate than using towers just because there are so many more WiFi access points (i.e. radios in routers) around. The position of each WiFi AP needs to be recorded in a database and used in the calculations, which is what Skyhook has been doing since 2008.  Another advantage to this method is that works well indoors, although it usually requires additional WiFi beacons to get the accuracy down to 5-10 meters.  Companies like ZuluTime, Aisle411, and PointInside have been perfecting this approach for retailers like Meijer, Walgreens, and HomeDepot. Keep in mind that a mobile phone doesn't have to connect to the WiFi network in order for it to be located.  The WiFi radio in the phone only needs to be on.  Even when not connected, WiFi radios talk to each other to prepare for a possible connection. 4. Hybrid Approaches Naturally the most accurate approach is to combine the approaches described above.  The more available data points, the greater the accuracy.  Companies like ShopKick like to add in acoustic triangulation using the phone's microphone, and NearBuy can use video analytics to increase accuracy. 5. Magnetic Fields The latest approach, and this one is really new, takes a page from the animal kingdom.  As you've probably learned from guys like Marlin Perkins, some animals use the Earth's magnetic fields to navigate.  By recording magnetic variations within a store, then matching those readings with ones from a consumer's phone, location can be accurately determined.  At least that's the approach IndoorAtlas is taking, and the science seems to bear out.  It works well indoors, and doesn't require retailers to purchase any additional hardware.  Keep an eye on this one.

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• Code Contracts: validating arrays and collections

  - by DigiMortal

  Validating collections before using them is very common task when we use built-in generic types for our collections. In this posting I will show you how to validate collections using code contracts. It is cool how much awful looking code you can avoid using code contracts. Failing code Let’s suppose we have method that calculates sum of all invoices in collection. We have class Invoice and one of properties it has is Sum. I don’t introduce here any complex calculations on invoices because we have another problem to solve in this topic. Here is our code. public static decimal CalculateTotal(IList<Invoice> invoices) {     var sum = invoices.Sum(p => p.Sum);     return sum; } This method is very simple but it fails when invoices list contains at least one null. Of course, we can test if invoice is null but having nulls in lists like this is not good idea – it opens green way for different coding bugs in system. Our goal is to react to bugs ASAP at the nearest place they occur. There is one more way how to make our method fail. It happens when invoices is null. I thing it is also one common bugs during development and it even happens in production environments under some conditions that are usually hardly met. Now let’s protect our little calculation method with code contracts. We need two contracts: invoices cannot be null invoices cannot contain any nulls Our first contract is easy but how to write the second one? Solution: Contract.ForAll Preconditions in code are checked using Contract.Ensures method. This method takes boolean value as argument that sais if contract holds or not. There is also method Contract.ForAll that takes collection and predicate that must hold for that collection. Nice thing is ForAll returns boolean. So, we have very simple solution. public static decimal CalculateTotal(IList<Invoice> invoices) {     Contract.Requires(invoices != null);     Contract.Requires(Contract.ForAll<Invoice>(invoices, p => p != null));       var sum = invoices.Sum(p => p.Sum);     return sum; } And here are some lines of code you can use to test the contracts quickly. var invoices = new List<Invoice>(); invoices.Add(new Invoice()); invoices.Add(null); invoices.Add(new Invoice()); //CalculateTotal(null); CalculateTotal(invoices); If your code is covered with unit tests then I suggest you to write tests to check that these contracts hold for every code run. Conclusion Although it seemed at first place that checking all elements in collection may end up with for-loops that does not look so nice we were able to solve our problem nicely. ForAll method of contract class offered us simple mechanism to check collections and it does it smoothly the code-contracts-way. P.S. I suggest you also read devlicio.us blog posting Validating Collections with Code Contracts by Derik Whittaker.

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• AccelerometerInput XNA GameComponent

  - by Michael B. McLaughlin

  Bad accelerometer controls kill otherwise good games. I decided to try to do something about it. So I create an XNA GameComponent called AccelerometerInput. It’s still a beta project but you are welcome to try it, use it, modify it, etc. I’m releasing under the terms of the Microsoft Public License. Important info: First, it only supports tilt-style controls currently. I have not implemented motion-style controls yet (and make no promises as to when I might find time to do so). Second, I commented it heavily so that you can (hopefully) understand what it is doing. Please read the comments and examine the sample game for a usage overview. There are configurable parameters which I encourage you to make use of (both by modifying the default values where your testing shows it to be appropriate and also by implementing a calibration mechanism in your game that lets the user adjust those configurable values based on his or her own circumstances). Third, even with this code, accelerometer controls are still a fairly advanced topic area; you will likely find nothing but disappointment if you simply plunk this into some project without testing it on a device (or preferably on several devices). Fourth, if you do try this code and find that something doesn’t work as expected on your phone, please let me know as I want to improve it and can only do so with your help. Let me know what phone model it is, what you tried doing, what you expected, and what result you had instead. I may or may not be able to incorporate it into the code, but I can let others know at the very least so that they can make appropriate modifications to their games (I’m hopeful that all phones are reasonably similar in their workings and require, at most, a slight calibration change, but I simply don’t know). Fifth, although I’ll do my best to answer any questions you may have about it, I’m very busy with a number of things currently so it might take a little while. Please look through the code and examine the comments and sample game first before asking any questions. It’s likely that the answer is in there. If not, or if you just aren’t really sure, ask away. Sixth, there are differences between a portrait-mode game and a landscape mode game (specifically in the appropriate default tilt adjustment for toward the user/away from the user calculations). This is documented and the default is set for landscape. If you use this for a portrait game, make the appropriate change (look for the TODO: comment in AccelerometerInput.cs). Seventh, no provision whatsoever is made for disabling screen locking. It is up to you to implement that and to take appropriate measures to detect when the user has been idle for too long and timeout the game. That code is very game-specific. If you have questions about such matters, consult the relevant MSDN documentation and, if you still have questions, visit the App Hub forums and ask there. I answer questions there a lot and so I may even stumble across your question and answer it. But that’s a much better forum than the comments section here for questions of that sort so I would appreciate it if you asked idle detection-related questions there (or on some other suitable site that you may be more familiar and comfortable with). Eighth, this is an XNA GameComponent intended for XNA-based games on WP7. A sufficiently knowledgeable Silverlight developer should have no problem adapting it for use in a Silverlight game or app. I may create a Silverlight version at some point myself. Right now I do not have the time, unfortunately. Ok. Without further ado: http://www.bobtacoindustries.com/developers/utils/AccelerometerInput.zip Have a great St. Patrick’s Day!

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• Oracle Retail Mobile Point-of-Service

  - by David Dorf

  When most people discuss mobile in retail, they immediately go to shopping applications.  While I agree the consumer side of mobile is huge, I believe its also important to arm store associates with mobile tools.  There are around a dozen major roll-outs of mobile POS to chain retailers, and all have been successful.  This does not, however, signal the demise of traditional registers.  Retailers will adopt mobile POS slowly and reduce the number of fixed registers over time, but there's likely to be a combination of both for the foreseeable future.  Even Apple retains at least one fixed register in every store, you just have to know where to look. The business benefits for mobile POS are pretty straightforward: 1. Faster checkout.  Walmart's CFO recently reported that for every second they shave off the average transaction time, they can potentially save $12M a year in labor.  I think its more likely that labor will be redeployed to enhance the customer experience. 2. Smarter associates.  The sales associates on the floor need the same access to information that consumers have, if not more.  They need ready access to product details, reviews, inventory, etc. to meet consumer expectations.  In a recent study, 40% of consumers said a savvy store associate can impact their final product selection more than a website. 3. Lower costs.  Mobile POS hardware (iPod touch + sled) costs about a fifth of fixed registers, not to mention the reclaimed space that can be used for product displays. But almost all Mobile POS solutions can claim those benefits equally.  Where there's differentiation is on the technical side.  Oracle recently announced availability of the Oracle Retail Mobile Point-of-Service, and it has three big technology advantages in the market: 1. Portable. We used a popular open-source component called PhoneGap that abstracts the app from the underlying OS and hardware so that iOS, Android, and other platforms could be supported.  Further, we used Web technologies such as HTML5 and JavaScript, which are commonly known by many programmers, as opposed to ObjectiveC which is more difficult to find.  The screen can adjust to different form-factors and sizes, just like you see with browsers.  In the future when a new, zippy device gets released, retailers will have the option to move to that device more easily than if they used a native app. 2. Flexible.  Our Mobile POS is free with the Oracle Retail Point-of-Service product.  Retailers can use any combination of fixed and mobile registers, and those ratios can change as required.  Perhaps start with 1 mobile and 4 fixed per store, then transition over time to 4 mobile and 1 fixed without any additional software licenses.  Our scalable solution supports lots of combinations. 3. Consistent.  Because our Mobile POS is fully integrated to our traditional POS, the same business logic is reused.  Third-party Mobile POS solutions often handle pricing, promotions, and tax calculations separately leading to possible inconsistencies within the store.  That won't happen with Oracle's solution. For many retailers, Mobile POS can lower costs, increase customer service, and generally enhance a consumer's in-store experience.  Apple led the way, but lots of other retailers are discovering the many benefits of adding mobile capabilities in their stores.  Just be sure to examine both the business and technology benefits so you get the most value from your solution for the longest period of time.

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• Advanced Record-Level Business Intelligence with Inner Queries

  - by gt0084e1

  While business intelligence is generally applied at an aggregate level to large data sets, it's often useful to provide a more streamlined insight into an individual records or to be able to sort and rank them. For instance, a salesperson looking at a specific customer could benefit from basic stats on that account. A marketer trying to define an ideal customer could pull the top entries and look for insights or patterns. Inner queries let you do sophisticated analysis without the overhead of traditional BI or OLAP technologies like Analysis Services. Example - Order History Constancy Let's assume that management has realized that the best thing for our business is to have customers ordering every month. We'll need to identify and rank customers based on how consistently they buy and when their last purchase was so sales & marketing can respond accordingly. Our current application may not be able to provide this and adding an OLAP server like SSAS may be overkill for our needs. Luckily, SQL Server provides the ability to do relatively sophisticated analytics via inner queries. Here's the kind of output we'd like to see. Creating the Queries Before you create a view, you need to create the SQL query that does the calculations. Here we are calculating the total number of orders as well as the number of months since the last order. These fields might be very useful to sort by but may not be available in the app. This approach provides a very streamlined and high performance method of delivering actionable information without radically changing the application. It's also works very well with self-service reporting tools like Izenda. SELECT CustomerID,CompanyName, ( SELECT COUNT(OrderID) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID ) As Orders, DATEDIFF(mm, ( SELECT Max(OrderDate) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID) ,getdate() ) AS MonthsSinceLastOrder FROM Customers Creating Views To turn this or any query into a view, just put CREATE VIEW AS before it. If you want to change it use the statement ALTER VIEW AS. Creating Computed Columns If you'd prefer not to create a view, inner queries can also be applied by using computed columns. Place you SQL in the (Formula) field of the Computed Column Specification or check out this article here. Advanced Scoring and Ranking One of the best uses for this approach is to score leads based on multiple fields. For instance, you may be in a business where customers that don't order every month require more persistent follow up. You could devise a simple formula that shows the continuity of an account. If they ordered every month since their first order, they would be at 100 indicating that they have been ordering 100% of the time. Here's the query that would calculate that. It uses a few SQL tricks to make this happen. We are extracting the count of unique months and then dividing by the months since initial order. This query will give you the following information which can be used to help sales and marketing now where to focus. You could sort by this percentage to know where to start calling or to find patterns describing your best customers. Number of orders First Order Date Last Order Date Percentage of months order was placed since last order. SELECT CustomerID, (SELECT COUNT(OrderID) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID) As Orders, (SELECT Max(OrderDate) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID) AS LastOrder, (SELECT Min(OrderDate) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID) AS FirstOrder, DATEDIFF(mm,(SELECT Min(OrderDate) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID),getdate()) AS MonthsSinceFirstOrder, 100*(SELECT COUNT(DISTINCT 100*DATEPART(yy,OrderDate) + DATEPART(mm,OrderDate)) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID) / DATEDIFF(mm,(SELECT Min(OrderDate) FROM Orders WHERE Orders.CustomerID = Customers.CustomerID),getdate()) As OrderPercent FROM Customers

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• Incorrect lighting results with deferred rendering

  - by Lasse

  I am trying to render a light-pass to a texture which I will later apply on the scene. But I seem to calculate the light position wrong. I am working on view-space. In the image above, I am outputting the attenuation of a point light which is currently covering the whole screen. The light is at 0,10,0 position, and I transform it to view-space first: Vector4 pos; Vector4 tmp = new Vector4 (light.Position, 1); // Transform light position for shader Vector4.Transform (ref tmp, ref Camera.ViewMatrix, out pos); shader.SendUniform ("LightViewPosition", ref pos); Now to me that does not look as it should. What I think it should look like is that the white area should be on the center of the scene. The camera is at the corner of the scene, and it seems as if the light would move along with the camera. Here's the fragment shader code: void main(){ // default black color vec3 color = vec3(0); // Pixel coordinates on screen without depth vec2 PixelCoordinates = gl_FragCoord.xy / ScreenSize; // Get pixel position using depth from texture vec4 depthtexel = texture( DepthTexture, PixelCoordinates ); float depthSample = unpack_depth(depthtexel); // Get pixel coordinates on camera-space by multiplying the // coordinate on screen-space by inverse projection matrix vec4 world = (ImP * RemapMatrix * vec4(PixelCoordinates, depthSample, 1.0)); // Undo the perspective calculations vec3 pixelPosition = (world.xyz / world.w) * 3; // How far the light should reach from it's point of origin float lightReach = LightColor.a / 2; // Vector in between light and pixel vec3 lightDir = (LightViewPosition.xyz - pixelPosition); float lightDistance = length(lightDir); vec3 lightDirN = normalize(lightDir); // Discard pixels too far from light source //if(lightReach < lightDistance) discard; // Get normal from texture vec3 normal = normalize((texture( NormalTexture, PixelCoordinates ).xyz * 2) - 1); // Half vector between the light direction and eye, used for specular component vec3 halfVector = normalize(lightDirN + normalize(-pixelPosition)); // Dot product of normal and light direction float NdotL = dot(normal, lightDirN); float attenuation = pow(lightReach / lightDistance, LightFalloff); // If pixel is lit by the light if(NdotL > 0) { // I have moved stuff from here to above so I can debug them. // Diffuse light color color += LightColor.rgb * NdotL * attenuation; // Specular light color color += LightColor.xyz * pow(max(dot(halfVector, normal), 0.0), 4.0) * attenuation; } RT0 = vec4(color, 1); //RT0 = vec4(pixelPosition, 1); //RT0 = vec4(depthSample, depthSample, depthSample, 1); //RT0 = vec4(NdotL, NdotL, NdotL, 1); RT0 = vec4(attenuation, attenuation, attenuation, 1); //RT0 = vec4(lightReach, lightReach, lightReach, 1); //RT0 = depthtexel; //RT0 = 100 / vec4(lightDistance, lightDistance, lightDistance, 1); //RT0 = vec4(lightDirN, 1); //RT0 = vec4(halfVector, 1); //RT0 = vec4(LightColor.xyz,1); //RT0 = vec4(LightViewPosition.xyz/100, 1); //RT0 = vec4(LightPosition.xyz, 1); //RT0 = vec4(normal,1); } What am I doing wrong here?

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• Numerically stable(ish) method of getting Y-intercept of mouse position?

  - by Fraser

  I'm trying to unproject the mouse position to get the position on the X-Z plane of a ray cast from the mouse. The camera is fully controllable by the user. Right now, the algorithm I'm using is... Unproject the mouse into the camera to get the ray: Vector3 p1 = Vector3.Unproject(new Vector3(x, y, 0), 0, 0, width, height, nearPlane, farPlane, viewProj; Vector3 p2 = Vector3.Unproject(new Vector3(x, y, 1), 0, 0, width, height, nearPlane, farPlane, viewProj); Vector3 dir = p2 - p1; dir.Normalize(); Ray ray = Ray(p1, dir); Then get the Y-intercept by using algebra: float t = -ray.Position.Y / ray.Direction.Y; Vector3 p = ray.Position + t * ray.Direction; The problem is that the projected position is "jumpy". As I make small adjustments to the mouse position, the projected point moves in strange ways. For example, if I move the mouse one pixel up, it will sometimes move the projected position down, but when I move it a second pixel, the project position will jump back to the mouse's location. The projected location is always close to where it should be, but it does not smoothly follow a moving mouse. The problem intensifies as I zoom the camera out. I believe the problem is caused by numeric instability. I can make minor improvements to this by doing some computations at double precision, and possibly abusing the fact that floating point calculations are done at 80-bit precision on x86, however before I start micro-optimizing this and getting deep into how the CLR handles floating point, I was wondering if there's an algorithmic change I can do to improve this? EDIT: A little snooping around in .NET Reflector on SlimDX.dll: public static Vector3 Unproject(Vector3 vector, float x, float y, float width, float height, float minZ, float maxZ, Matrix worldViewProjection) { Vector3 coordinate = new Vector3(); Matrix result = new Matrix(); Matrix.Invert(ref worldViewProjection, out result); coordinate.X = (float) ((((vector.X - x) / ((double) width)) * 2.0) - 1.0); coordinate.Y = (float) -((((vector.Y - y) / ((double) height)) * 2.0) - 1.0); coordinate.Z = (vector.Z - minZ) / (maxZ - minZ); TransformCoordinate(ref coordinate, ref result, out coordinate); return coordinate; } // ... public static void TransformCoordinate(ref Vector3 coordinate, ref Matrix transformation, out Vector3 result) { Vector3 vector; Vector4 vector2 = new Vector4 { X = (((coordinate.Y * transformation.M21) + (coordinate.X * transformation.M11)) + (coordinate.Z * transformation.M31)) + transformation.M41, Y = (((coordinate.Y * transformation.M22) + (coordinate.X * transformation.M12)) + (coordinate.Z * transformation.M32)) + transformation.M42, Z = (((coordinate.Y * transformation.M23) + (coordinate.X * transformation.M13)) + (coordinate.Z * transformation.M33)) + transformation.M43 }; float num = (float) (1.0 / ((((transformation.M24 * coordinate.Y) + (transformation.M14 * coordinate.X)) + (coordinate.Z * transformation.M34)) + transformation.M44)); vector2.W = num; vector.X = vector2.X * num; vector.Y = vector2.Y * num; vector.Z = vector2.Z * num; result = vector; } ...which seems to be a pretty standard method of unprojecting a point from a projection matrix, however this serves to introduce another point of possible instability. Still, I'd like to stick with the SlimDX Unproject routine rather than writing my own unless it's really necessary.

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• Texture displays on Android emulator but not on device

  - by Rob

  I have written a simple UI which takes an image (256x256) and maps it to a rectangle. This works perfectly on the emulator however on the phone the texture does not show, I see only a white rectangle. This is my code: public void onSurfaceCreated(GL10 gl, EGLConfig config) { byteBuffer = ByteBuffer.allocateDirect(shape.length * 4); byteBuffer.order(ByteOrder.nativeOrder()); vertexBuffer = byteBuffer.asFloatBuffer(); vertexBuffer.put(cardshape); vertexBuffer.position(0); byteBuffer = ByteBuffer.allocateDirect(shape.length * 4); byteBuffer.order(ByteOrder.nativeOrder()); textureBuffer = byteBuffer.asFloatBuffer(); textureBuffer.put(textureshape); textureBuffer.position(0); // Set the background color to black ( rgba ). gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Enable Smooth Shading, default not really needed. gl.glShadeModel(GL10.GL_SMOOTH); // Depth buffer setup. gl.glClearDepthf(1.0f); // Enables depth testing. gl.glEnable(GL10.GL_DEPTH_TEST); // The type of depth testing to do. gl.glDepthFunc(GL10.GL_LEQUAL); // Really nice perspective calculations. gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); gl.glEnable(GL10.GL_TEXTURE_2D); loadGLTexture(gl); } public void onDrawFrame(GL10 gl) { gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glDisable(GL10.GL_DEPTH_TEST); gl.glMatrixMode(GL10.GL_PROJECTION); // Select Projection gl.glPushMatrix(); // Push The Matrix gl.glLoadIdentity(); // Reset The Matrix gl.glOrthof(0f, 480f, 0f, 800f, -1f, 1f); gl.glMatrixMode(GL10.GL_MODELVIEW); // Select Modelview Matrix gl.glPushMatrix(); // Push The Matrix gl.glLoadIdentity(); // Reset The Matrix gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glLoadIdentity(); gl.glTranslatef(card.x, card.y, 0.0f); gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]); //activates texture to be used now gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertexBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); } public void onSurfaceChanged(GL10 gl, int width, int height) { // Sets the current view port to the new size. gl.glViewport(0, 0, width, height); // Select the projection matrix gl.glMatrixMode(GL10.GL_PROJECTION); // Reset the projection matrix gl.glLoadIdentity(); // Calculate the aspect ratio of the window GLU.gluPerspective(gl, 45.0f, (float) width / (float) height, 0.1f, 100.0f); // Select the modelview matrix gl.glMatrixMode(GL10.GL_MODELVIEW); // Reset the modelview matrix gl.glLoadIdentity(); } public int[] texture = new int[1]; public void loadGLTexture(GL10 gl) { // loading texture Bitmap bitmap; bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.image); // generate one texture pointer gl.glGenTextures(0, texture, 0); //adds texture id to texture array // ...and bind it to our array gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]); //activates texture to be used now // create nearest filtered texture gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); // Use Android GLUtils to specify a two-dimensional texture image from our bitmap GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); // Clean up bitmap.recycle(); } As per many other similar issues and resolutions on the web i have tried setting the minsdkversion is 3, loading the bitmap via an input stream bitmap = BitmapFactory.decodeStream(is), setting BitmapFactory.Options.inScaled to false, putting the images in the nodpi folder and putting them in the raw folder.. all of which didn't help. I'm not really sure what else to try..

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• (CanvsEngine) Collission problem ( TypeError: this._polygon[this._frame] is undefined) [on hold]

  - by user2127102

  How can i fix this error TypeError: this._polygon[this._frame] is undefined Heres my code: html: <!DOCTYPE Html> <head> <meta charset="utf-8"> <title>Project</title> <link href="css/style.css" rel="stylesheet"> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script> <script src="js/canvasengine-1.3.0.all.min.js"></script> <script src="js/extends/Input.js"></script> <script src="main.js"></script> </head> <body> <canvas id="window"></canvas> </body> main.js: var canvas = CE.defines("window"). extend(Input). ready(function() { canvas.Scene.call("Game"); }); canvas.Scene.new({ name: "Game", materials: { images: { player: "img/character.png", Wall: "img/TestWall.png" } }, ready: function(stage) { var _canvas = this.getCanvas(); _canvas.setSize("browser", "strech"); this.Player = Class.new("Entity", [stage]); this.Player.el.drawImage("player"); stage.append(this.Player.el); this.Wall = Class.new("Entity", [stage]); this.Wall.el.drawImage("Wall"); this.Wall.position(300, 0); stage.append(this.Wall.el); }, render: function(stage) { //Controls ====== //Control calculations var self = this; this.Mover_A; this.Mover_D; this.Mover_W; this.Mover_S; canvas.Input.keyDown(Input.A, function(e) { self.Mover_A = true; }); canvas.Input.keyDown(Input.D, function(e) { self.Mover_D = true; }); canvas.Input.keyDown(Input.W, function(e) { self.Mover_W = true; }); canvas.Input.keyDown(Input.S, function(e) { self.Mover_S = true; console.log(self.Mover_S); }); canvas.Input.keyUp(Input.A, function(e) { self.Mover_A = false; }); canvas.Input.keyUp(Input.D, function(e) { self.Mover_D = false; }); canvas.Input.keyUp(Input.W, function(e) { self.Mover_W = false; }); canvas.Input.keyUp(Input.S, function(e) { self.Mover_S = false; }); x = 0; y = 0; if(this.Mover_A)x -= 1.5; //A if(this.Mover_D)x += 1.5;//D if(this.Mover_W)y -= 1.5;//W if(this.Mover_S)y += 1.5; //S this.Player.move(x, y); this.Player.hit("over", [this.Wall], function(state, el) { this.Player.move(x * -1, y * -1); }); //End Controls ===== stage.refresh(); } });

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• The Social Enterprise: Gangnam Style

  - by Mike Stiles

  Are only small and medium businesses able to put social strategies in place, generate consistent, compelling content for customers, and be nimble enough to listen and respond to the social communities they build? Or are enterprise organizations eagerly and effectively adopting social as well? It depends on whom inside the organization you ask. A study from Attensity looked at who “gets” social inside enterprise organizations. The results were unsurprising. Mostly, Generation X and Y employees who came of age with social as part of their lives and as a key communications vehicle understand it. Imagine being a 25-year-old at a company that bans employees from accessing Facebook at work. You may as well tell them they can’t use phones and must do all calculations on an abacus. To them, such policy is absent of real-world logic and signals to them the organization is destined to be the victim of an up-and-comer. After that, it’s senior management that gets social. You don’t get to be in senior management without reading a few things and paying attention. Most senior managers are well aware of the impact social has had and will have, though they may be unsure of what to do about it. The better ones will utilize those on the inside who do inherently know how to communicate and build virtual relationships using social. The very best will get the past out of the way for these social innovators, so the new communications can be enacted minus counterproductive dictums, double-clutching, meeting-creep, and all the other fading internal practices that water down content and impede change. Organizationally, the Attensity study found 81% of enterprise companies believe failing to embrace social will result in their being left behind. Yet our old friend fear still has many captive in its clutches. 79% feel overwhelmed by the volume of social data available, something a social technology partner with goal-oriented analytics expertise could go a long way toward alleviating. Then there’s the fear of social having a negative impact. This comes from a lack of belief in the product, the customer service, or both. The public uses social not to go out and slay brands. They’re using it to be honest. If the fear is that honesty will reflect badly on the brand, the brand has much bigger, broader problems than what happens on Facebook. Sadly, most enterprise organizations still see social as a megaphone, a one-way channel with which to hit people with ads. They either don’t understand social relationships, or don’t want any. The truly unenlightened manager will always say, “We help them by selling them our stuff.” “Brand affinity” is a term, it’s just not one assigned much value in enterprise organizations. Which brings us to Psy, the Korean performer whose Internet video phenom “Gangnam Style,” as of this writing, has been viewed 438,550,238 times on YouTube. It’s bigger than anything a brand will probably ever publish. Most brands would never have seen the point of making or publishing it. But a funny thing happened on the way to Internet success. The video literally doubled the stock price of Psy’s father’s software firm. NH Investment and Securities said, "The positive sentiment has attracted investors just because of the fact the company is owned by Psy's father and uncle.” The company wasn’t mentioned or seen in the video in any way, yet reaped tangible rewards just for being tangentially associated with it. Imagine your brand being visibly and directly responsible for such a smash and tell me it’s worthless. When enterprise organizations embrace the value of igniting passions, making people happier, solving their problems, informing them, helping them have fun, etc., then they will have fully embraced social, and will reap the brand affinity rewards of heightened awareness, brand loyalty and yes, sales.

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• Where are my date ranges in Analytics coming from?

  - by Jeffrey McDaniel

  In the P6 Reporting Database there are two main tables to consider when viewing time - W_DAY_D and W_Calendar_FS.  W_DAY_D is populated internally during the ETL process and will provide a row for every day in the given time range. Each row will contain aspects of that day such as calendar year, month, week, quarter, etc. to allow it to be used in the time element when creating requests in Analytics to group data into these time granularities. W_Calendar_FS is used for calculations such as spreads, but is also based on the same set date range. The min and max day_dt (W_DAY_D) and daydate (W_Calendar_FS) will be related to the date range defined, which is a start date and a rolling interval plus a certain range. Generally start date plus 3 years.  In P6 Reporting Database 2.0 this date range was defined in the Configuration utility.  As of P6 Reporting Database 3.0, with the introduction of the Extended Schema this date range is set in the P6 web application. The Extended Schema uses this date range to calculate the data for near real time reporting in P6.  This same date range is validated and used for the P6 Reporting Database.  The rolling date range means if today is April 1, 2010 and the rolling interval is set to three years, the min date will be 1/1/2010 and the max date will be 4/1/2013.  1/1/2010 will be the min date because we always back fill to the beginning of the year. On April 2nd, the Extended schema services are run and the date range is adjusted there to move the max date forward to 4/2/2013.  When the ETL process is run the Reporting Database will pick up this change and also adjust the max date on the W_DAY_D and W_Calendar_FS. There are scenarios where date ranges affecting areas like resource limit may not be adjusted until a change occurs to cause a recalculation, but based on general system usage these dates in these tables will progress forward with the rolling intervals. Choosing a large date range can have an effect on the ETL process for the P6 Reporting Database. The extract portion of the process will pull spread data over into the STAR. The date range defines how long activity and resource assignment spread data is spread out in these tables. If an activity lasts 5 days it will have 5 days of spread data. If a project lasts 5 years, and the date range is 3 years the spread data after that 3 year date range will be bucketed into the last day in the date range. For the overall project and even the activity level you will still see the correct total values.  You just would not be able to see the daily spread 5 years from now. This is an important question when choosing your date range, do you really need to see spread data down to the day 5 years in the future?  Generally this amount of granularity years in the future is not needed. Remember all those values 5, 10, 15, 20 years in the future are still available to report on they would be in more of a summary format on the activity or project.  The data is always there, the level of granularity is the decision.

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• Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

  - by Mike

  EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

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• Rethinking Oracle Optimizer Statistics for P6 Part 2

  - by Brian Diehl

  In the previous post (Part 1), I tried to draw some key insights about the relationship between P6 and Oracle Optimizer Statistics.  The first is that average cardinality has the greatest impact on query optimization and that the particular queries generated by P6 are more likely to use this average during calculations. The second is that these are statistics that are unlikely to change greatly over the life of the application. Ultimately, our goal is to get the best query optimization possible.  Or is it? Stability No application administrator wants to get the call at 9am that their application users cannot get there work done because everything is running slow. This is a possibility with a regularly scheduled nightly collection of statistics. It may not just be slow performance, but a complete loss of service because one or more queries are optimized poorly. Ideally, this should not be the case. The database optimizer should make better decisions with more up-to-date data. Better statistics may give incremental performance benefit. However, this benefit must be balanced against the potential cost of system down time.  It is stability that we ultimately desire and not absolute optimal performance. We do want the benefit from more accurate statistics and better query plans, but not at the risk of an unusable system. As a result, I've developed the following methodology around managing database statistics for the P6 database.  1. No Automatic Re-Gathering - The daily, weekly, or other interval of statistic gathering is unlikely to be beneficial. Quite the opposite. It is more likely to cause problems. 2. Smart Re-Gathering - The time to collect statistics is when things have changed significantly. For a new installation of P6, this is happening more often because the data is growing from a few rows to thousands and more. But for a mature system, the data is not changing significantly from week-to-week. There are times to collect statistics: New releases of the application Changes in the underlying hardware or software versions (ex. new Oracle RDBMS version) When additional user groups are added. The new groups may use the software in significantly different ways. After significant changes in the data. This may be monthly, quarterly or yearly.  3. Always Test - If you take away one thing from this post, it would be to always have a plan to test after changing statistics. In reality, statistics can be collected as often as you desire provided there are tests in place to verify that performance is the same or better. These might be automated tests or simply a manual script of application functions. 4. Have a Way Out - Never change the statistics without a way to return to the previous set. Think of the statistics as one part of the overall application code that also includes the source code--both application and RDBMS. It would be foolish to change to the new code without a way to get back to the previous version. In the final post, I will talk about the actual script I created for P6 PMDB and possible future direction for managing query performance. 

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• Making user input/math on data fast, unlike excel type programs

  - by proGrammar

  I'm creating a research platform solely for myself to do some research on data. Programs like excel are terribly slow for me so I'm trying to come up with another solution. Originally I used excel. A1 was the cell that contained the data and all other cells in use calculated something on A1, or on other cells, that all could be in the end traced to A1. A1 was like an element of an array, I then I incremented it to go through all my data. This was way too slow. So the only other option I found originally was to hand code in c# the calculations inside a loop. Then I simply recompiled each time I changed my math. This was terribly slow to do and I had to order everything correctly so things would update correctly (dependencies). I could have also used events, but hand coding events for each cell like calculation would also be very slow. Next I created an application to read Excel and to perfectly imitate it. Which is what I now use. Basically I write formulas onto a fraction of my data to get live results inside excel. Then my program reads excel, writes another c# program, compiles it, and runs that program which runs my excel created formulas through a lot more data a whole lot faster. The advantage being my application dependency sorts everything (or I could use events) so I don't have to (like excel does) And of course the speed. But now its not a single application anymore. Instead its 2 applications, one which only reads my formulas and writes another program. The other one being the result which only lives for a short while before I do other runs through my data with different formulas / settings. So I can't see multiple results at one time without introducing even more programs like a database or at least having the 2 applications talking to each other. My idea was to have a dll that would be written, compiled, loaded, and unloaded again and again. So a self-updating program, sort of. But apparently that's not possible without another appdomain which means data has to be marshaled to be moved between the appdomains. Which would slow things down, not for summaries, but for other stuff I need to do with all my data. I'm also forgetting to mention a huge problem with restarting an application again and again which is having to reload ALL my data into memory again and again. But its still a whole lot faster than excel. I'm really super puzzled as to what people do when they want to research data fast. I'm completely unable to have a program accept user input and having it fast. My understanding is that it would have to do things like excel which is to evaluate strings again and again. So my only option is to repeatedly compile applications. Do I have a correct understanding on computer science? I've only just began programming, and didn't think I would have to learn much to do some simple math on data. My understanding is its either compiling my user defined stuff to a program or evaluating them from a string or something stupid again and again. And my only option is to probably switch operating systems or something to be able to have a program compile and run itself without stopping (writing/compiling dll, loading dll to program, unloading, and repeating). Can someone give me some idea on how computers work? Is anything better possible? Like a running program, that can accept user input and compile it and then unload it later? I mean heck operating systems dont need to be RESTARTED with every change to user input. What is this the cave man days? Sorry, it's just so super frustrating not knowing what one can do, and can't do. If only I could understand and learn this stuff fast enough.

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• Is it possible for a WPF control to have an ActualWidth and ActualHeight if it has never been render

  - by DanM

  I need a Viewport3D for the sole purpose of doing geometric calculations using Petzold.Media3D.ViewportInfo. I do now want to place it in a Window. I'm creating a Viewport3D using the following code: private Viewport3D CreateViewport(MainSettings settings) { var cameraPosition = new Point3D(0, 0, settings.CameraHeight); var cameraLookDirection = new Vector3D(0, 0, -1); var cameraUpDirection = new Vector3D(0, 1, 0); var camera = new PerspectiveCamera { Position = cameraPosition, LookDirection = cameraLookDirection, UpDirection = cameraUpDirection }; var viewport = new Viewport3D { Camera = camera, Width = settings.ViewportWidth, Height = settings.ViewportHeight }; return viewport; } Later, I'm attempting to use this viewport to convert the mouse location to a 3D location using this method: public Point3D? Point2dToPoint3d(Point point) { var range = new LineRange(); var isValid = ViewportInfo.Point2DtoPoint3D(_viewport, point, out range); if (isValid) return range.PointFromZ(0); else return null; } Unfortunately, it's not working. I think the reason is that the ActualWidth and ActualHeight of the viewport and both zero (and these are read-only properties, so I can't set them manually). (I have tested the exact same with an actual rendered Viewport3D, so I know the issue is not with my converter method.) Any idea how I can get WPF to assign the ActualWidth and ActualHeight based on my Width and Height settings? I tried setting the HorizontalAlignment and VerticalAlignment to Left and Top, respectively, and I also messed with the MinWidth and MinHeight, but none of these properties had any effect on the ActualWidth or ActualHeight.

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• Android Canvas Coordinate System

  - by Mitch

  I'm trying to find information on how to change the coordinate system for the canvas. I have some vector data I'd like to draw to a canvas using things like circles and lines, but the data's coordinate system doesn't match the canvas coordinate system. Is there a way to map the units I'm using to the screen's units? I'm drawing to an ImageView which isn't taking up the entire display. If I have to do my own calculations prior to each drawing call, how to I find the width and height of my ImageView? The getWidth() and getHeight() calls I tried seem to be returning the entire canvas size and not the size of the ImageView which isn't helpful. I see some matrix stuff, is that something that will work for me? I tried to use the "public void scale(float sx, float sy)", but that works more like a pixel level zoom rather than a vector scale function by expanding each pixel. This means if the dimensions are increased to fit the screen, the line thickness is also increased. Update: After some research I'm starting to think there's no way to change coordinate systems to something else. I'll need to map all my coordinates to the screen's pixel coordinates and do so by modifying each vector. The getWidth() and getHeight() seem to be working better for me now. I can say what was wrong, but I suspect I can't use these methods inside the constructor.

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• Negative ItemCount in SharePoint Document Library

  - by ccomet

  What can be done about negative numbers in library item counts? ItemCount is a read-only property, what are you supposed to do when it is drastically incorrect? Earlier last week, I was doing some testing involving the copying and moving of files and folders from one document library to another. I was transfering the items from our actual document library to a sandbox "Test" library that I used to run all sorts of object model and workflow testing in before migrating to the public lists and libraries. I noticed that with files, things worked correctly, but when I copied a folder that had a file inside it (using SPFolder.CopyTo()), the item count for the test library did not actually update. Since this testing was mostly playing around, I paid it little heed. Today I was back in the test library to test a different workflow (regarding PDF conversion). While I was there, I decided to delete the folder I left last week since I didn't need it anymore. And that's when I saw the item count for the list drop to -1 in the All Site Content View. When I deleted the new PDF I had just uploaded, it then dropped to -2! I even checked with the object model... getting an instance of the library I checked the ItemCount property... lo and behold it was also -2. Is there any process which runs in the background, kinda like the one that cleans up workflow history, which will correct this kind of issue? Or is a programmer expected to keep watch for this kind of situation and come up with calculations to compensate the "count penalty", as it were?

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• Want custom title / image / description in facebook share link

  - by Ezop

  Hi! I am making a flash app that demonstrates potensial traffic injuries when driving at different speeds. I want the user to be able to share this information on facebook. However this demands that i can customize the text that will appear on facebook in some manner. I am making an url that is opened in a blank window (from the flash app itself). I specify the u and t parameters, putting the generated message as the t parameter. But this seems to always be overridden by the pages title. If i omit the title tag from the html code, the file name is used (also overriding the specified title). http://www.facebook.com/sharer.php?u=http://espentokerud.com/face/addiste.html&t=test; I also tried url-encoding the url, but to no avail. http://www.facebook.com/sharer.php?u=http%3a%2f%2fespentokerud.com%2fface%2faddiste.html&t=test; I also tried using the addthis API, but experience the same shortcomings. The funny thing is that if i post a swf, the title and description can be customized, and it is also possible to specify a screenshot. But if i dont post a swf, this seems to be ignored. I am aware that I can use meta tags on the html page to specify the thumbnail image, title and description, but some of this content has to be based on calculations inside the flash app. Can anyone help me out or point me in the right direction? I am thankful for any help!

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