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  • Is chess-like AI really inapplicable in turn-based strategy games?

    - by Joh
    Obviously, trying to apply the min-max algorithm on the complete tree of moves works only for small games (I apologize to all chess enthusiasts, by "small" I do not mean "simplistic"). For typical turn-based strategy games where the board is often wider than 100 tiles and all pieces in a side can move simultaneously, the min-max algorithm is inapplicable. I was wondering if a partial min-max algorithm which limits itself to N board configurations at each depth couldn't be good enough? Using a genetic algorithm, it might be possible to find a number of board configurations that are good wrt to the evaluation function. Hopefully, these configurations might also be good wrt to long-term goals. I would be surprised if this hasn't been thought of before and tried. Has it? How does it work?

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  • Why using the word "mechanism" in CS?

    - by Nick Rosencrantz
    I'm not sure about the usage of the word "mechanism" when in fact most of the time what is meant is an algorithm. For instance there's talk about Java's "thread-scheduling mechanism" - why not call it an algorithm and why borrow a term from mechanics where relations sometimes are the opposites than of computer science? I'm aware that an algorithm is considered a "mechanical solution" but is this really the case in fact when a lot of algorithm don't have mechanical representations for instance a file-sharing network that gets quicker and faster as the usage grows, that would be the reverse of a mechanical structure that would go slower when usage grows.

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  • Converting a bounded knapsack problem to 0/1 knapsack problem

    - by Ants
    I ran across a problem where goal was to use dynamic programming (instead of other approaches). There is a distance to be spanned, and a set of cables of different lengths. What is the minimum number of cables needed to span the distance exactly? To me this looked like a knapsack problem, but since there could be multiples of a particular length, it was a bounded knapsack problem, rather than a 0/1 knapsack problem. (Treat the value of each item to be its weight.) Taking the naive approach (and not caring about the expansion of the search space), the method I used to convert the bounded knapsack problem into a 0/1 knapsack problem, was simply break up the multiples into singles and apply the well-known dynamic programming algorithm. Unfortunately, this leads to sub-optimal results. For example, given cables: 1 x 10ft, 1 x 7ft, 1 x 6ft, 5 x 3ft, 6 x 2ft, 7 x 1ft If the target span is 13ft, the DP algorithm picks 7+6 to span the distance. A greedy algorithm would have picked 10+3, but it's a tie for minimum number of cables. The problem arises, when trying to span 15ft. The DP algorithm ended up picking 6+3+3+3 to get 4 cables, while the greedy algorithm correctly picks 10+3+2 for only 3 cables. Anyway, doing some light scanning of converting bounded to 0/1, it seems like the well-known approach to convert multiple items to { p, 2p, 4p ... }. My question is how does this conversion work if p+2p+4p does not add up to the number of multiple items. For example: I have 5 3ft cables. I can't very well add { 3, 2x3, 4x3 } because 3+2x3+4x3 5x3. Should I add { 3, 4x3 } instead? [I'm currently trying to grok the "Oregon Trail Knapsack Problem" paper, but it currently looks like the approach used there is not dynamic programming.]

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  • Marching squares: Finding multiple contours within one source field?

    - by TravisG
    Principally, this is a follow-up-question to a problem from a few weeks ago, even though this is about the algorithm in general without application to my actual problem. The algorithm basically searches through all lines in the picture, starting from the top left of it, until it finds a pixel that is a border. In pseudo-C++: int start = 0; for(int i=0; i<amount_of_pixels; ++i) { if(pixels[i] == border) { start = i; break; } } When it finds one, it starts the marching squares algorithm and finds the contour to whatever object the pixel belongs to. Let's say I have something like this: Where everything except the color white is a border. And have found the contour points of the first blob: For the general algorithm it's over. It found a contour and has done its job. How can I move on to the other two blobs to find their contours as well?

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  • Design pattern: static function call with input/output containers?

    - by Pavlo Dyban
    I work for a company in software research department. We use algorithms from our real software and wrap them so that we can use them for prototyping. Every time an algorithm interface changes, we need to adapt our wrappers respectively. Recently all algorithms have been refactored in such a manner that instead of accepting many different inputs and returning outputs via referenced parameters, they now accept one input data container and one output data container (the latter is passed by reference). Algorithm interface is limited to a static function call like that: class MyAlgorithm{ static bool calculate(MyAlgorithmInput input, MyAlgorithmOutput &output); } This is actually a very powerful design, though I have never seen it in a C++ programming environment before. Changes in the number of parameters and their data types are now encapsulated and they don't change the algorithm callback. In the latest algorithm which I have developed I used the same scheme. Now I want to know if this is a popular design pattern and what it is called.

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  • Is the Leptonica implementation of 'Modified Median Cut' not using the median at all?

    - by TheCodeJunkie
    I'm playing around a bit with image processing and decided to read up on how color quantization worked and after a bit of reading I found the Modified Median Cut Quantization algorithm. I've been reading the code of the C implementation in Leptonica library and came across something I thought was a bit odd. Now I want to stress that I am far from an expert in this area, not am I a math-head, so I am predicting that this all comes down to me not understanding all of it and not that the implementation of the algorithm is wrong at all. The algorithm states that the vbox should be split along the lagest axis and that it should be split using the following logic The largest axis is divided by locating the bin with the median pixel (by population), selecting the longer side, and dividing in the center of that side. We could have simply put the bin with the median pixel in the shorter side, but in the early stages of subdivision, this tends to put low density clusters (that are not considered in the subdivision) in the same vbox as part of a high density cluster that will outvote it in median vbox color, even with future median-based subdivisions. The algorithm used here is particularly important in early subdivisions, and 3is useful for giving visible but low population color clusters their own vbox. This has little effect on the subdivision of high density clusters, which ultimately will have roughly equal population in their vboxes. For the sake of the argument, let's assume that we have a vbox that we are in the process of splitting and that the red axis is the largest. In the Leptonica algorithm, on line 01297, the code appears to do the following Iterate over all the possible green and blue variations of the red color For each iteration it adds to the total number of pixels (population) it's found along the red axis For each red color it sum up the population of the current red and the previous ones, thus storing an accumulated value, for each red note: when I say 'red' I mean each point along the axis that is covered by the iteration, the actual color may not be red but contains a certain amount of red So for the sake of illustration, assume we have 9 "bins" along the red axis and that they have the following populations 4 8 20 16 1 9 12 8 8 After the iteration of all red bins, the partialsum array will contain the following count for the bins mentioned above 4 12 32 48 49 58 70 78 86 And total would have a value of 86 Once that's done it's time to perform the actual median cut and for the red axis this is performed on line 01346 It iterates over bins and check they accumulated sum. And here's the part that throws me of from the description of the algorithm. It looks for the first bin that has a value that is greater than total/2 Wouldn't total/2 mean that it is looking for a bin that has a value that is greater than the average value and not the median ? The median for the above bins would be 49 The use of 43 or 49 could potentially have a huge impact on how the boxes are split, even though the algorithm then proceeds by moving to the center of the larger side of where the matched value was.. Another thing that puzzles me a bit is that the paper specified that the bin with the median value should be located, but does not mention how to proceed if there are an even number of bins.. the median would be the result of (a+b)/2 and it's not guaranteed that any of the bins contains that population count. So this is what makes me thing that there are some approximations going on that are negligible because of how the split actually takes part at the center of the larger side of the selected bin. Sorry if it got a bit long winded, but I wanted to be as thoroughas I could because it's been driving me nuts for a couple of days now ;)

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  • Optimizing processing and management of large Java data arrays

    - by mikera
    I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

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  • Generic Event Generator and Handler from User Supplied Types?

    - by JaredBroad
    I'm trying to allow the user to supply custom data and manage the data with custom types. The user's algorithm will get time synchronized events pushed into the event handlers they define. I'm not sure if this is possible but here's the "proof of concept" code I'd like to build. It doesn't detect T in the for loop: "The type or namespace name 'T' could not be found" class Program { static void Main(string[] args) { Algorithm algo = new Algorithm(); Dictionary<Type, string[]> userDataSources = new Dictionary<Type, string[]>(); // "User" adding custom type and data source for algorithm to consume userDataSources.Add(typeof(Weather), new string[] { "temperature data1", "temperature data2" }); for (int i = 0; i < 2; i++) { foreach (Type T in userDataSources.Keys) { string line = userDataSources[typeof(T)][i]; //Iterate over CSV data.. var userObj = new T(line); algo.OnData < typeof(T) > (userObj); } } } //User's algorithm pattern. interface IAlgorithm<TData> where TData : class { void OnData<TData>(TData data); } //User's algorithm. class Algorithm : IAlgorithm<Weather> { //Handle Custom User Data public void OnData<Weather>(Weather data) { Console.WriteLine(data.date.ToString()); Console.ReadKey(); } } //Example "user" custom type. public class Weather { public DateTime date = new DateTime(); public double temperature = 0; public Weather(string line) { Console.WriteLine("Initializing weather object with: " + line); date = DateTime.Now; temperature = -1; } } }

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  • Big Data – Basics of Big Data Analytics – Day 18 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned the importance of the various components in Big Data Story. In this article we will understand what are the various analytics tasks we try to achieve with the Big Data and the list of the important tools in Big Data Story. When you have plenty of the data around you what is the first thing which comes to your mind? “What do all these data means?” Exactly – the same thought comes to my mind as well. I always wanted to know what all the data means and what meaningful information I can receive out of it. Most of the Big Data projects are built to retrieve various intelligence all this data contains within it. Let us take example of Facebook. When I look at my friends list of Facebook, I always want to ask many questions such as - On which date my maximum friends have a birthday? What is the most favorite film of my most of the friends so I can talk about it and engage them? What is the most liked placed to travel my friends? Which is the most disliked cousin for my friends in India and USA so when they travel, I do not take them there. There are many more questions I can think of. This illustrates that how important it is to have analysis of Big Data. Here are few of the kind of analysis listed which you can use with Big Data. Slicing and Dicing: This means breaking down your data into smaller set and understanding them one set at a time. This also helps to present various information in a variety of different user digestible ways. For example if you have data related to movies, you can use different slide and dice data in various formats like actors, movie length etc. Real Time Monitoring: This is very crucial in social media when there are any events happening and you wanted to measure the impact at the time when the event is happening. For example, if you are using twitter when there is a football match, you can watch what fans are talking about football match on twitter when the event is happening. Anomaly Predication and Modeling: If the business is running normal it is alright but if there are signs of trouble, everyone wants to know them early on the hand. Big Data analysis of various patterns can be very much helpful to predict future. Though it may not be always accurate but certain hints and signals can be very helpful. For example, lots of data can help conclude that if there is lots of rain it can increase the sell of umbrella. Text and Unstructured Data Analysis: unstructured data are now getting norm in the new world and they are a big part of the Big Data revolution. It is very important that we Extract, Transform and Load the unstructured data and make meaningful data out of it. For example, analysis of lots of images, one can predict that people like to use certain colors in certain months in their cloths. Big Data Analytics Solutions There are many different Big Data Analystics Solutions out in the market. It is impossible to list all of them so I will list a few of them over here. Tableau – This has to be one of the most popular visualization tools out in the big data market. SAS – A high performance analytics and infrastructure company IBM and Oracle – They have a range of tools for Big Data Analysis Tomorrow In tomorrow’s blog post we will discuss about very important components of the Big Data Ecosystem – Data Scientist. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • SQL SERVER – What are Actions in SSAS and How to Make a Reporting Action

    - by Pinal Dave
    Actions are used for customized browsing and drilling of data for the end-user. It’s an event that a user can raise while accessing the cube data. They are used in cube browsers like excel and are triggered when a user in a client tool clicks on a particular member, level, dimension, cells or may be the cube itself.  For example a user might be able to see a reporting services report, open a web page or drill through to detailed information related to the cube data. Analysis server supports 3 types of actions :- Report Drill-through Standard Actions In this blog post, I will explain the Reporting  action. The objective of this action is to return a report with details of the product where the sales amount is greater than 1000 in cube browser analysis. You need to create a basic cube first with the facts and dimensions you want in the analysis. Following are the steps to create reporting action. Go to SQL server data tools and open the analysis services project. Navigate to actions and click on new reporting action. 2.) Specify the name of the action and choose target type as attribute members since we have to create the action on members for a attribute. 3.) Specify the Target object of your report action. Target object would be the dimension or attribute on which you want the report to appear. In our case it is product name. 4.) Next you have to define the condition on which you want the report link to appear. However, this is an optional feature. In this example we are specifying a condition, which will check if the sales amount is greater than 10,000. So, that the link appears only for those products where the defined condition is met. 5.) Next you have to specify the server name on which the report is present, report path  and the report format in which you want the report to appear. 6.) Additionally you can specify the parameters. As with conditional expression, the parameters should be a valid MDX expression. The parameter name should be same as the one defined in the report. 7.) Deploy your solution after you are done with specifying parameters and go to the cube browser. 8.) Click on the analyze in excel button, this will open your cube in excel 9.) Make an analysis which shows product names and their sales amount. 10.) Right click on a product where sales amount is greater than 10000 you will see the reporting action link. Click on that and you will be taken to your reporting services report. 11.) Clicking on the link will take you to the URL of the report. I created this report using report project wizard in SQL server data tools. So, this is how we can launch reports from a cube browser. Similarly you can open web pages, run applications and a number of  other tasks. Koenig Solutions offers SSAS training which contains all Analysis Services including Reporting in great detail. In my next blog post I will talk about drill-through actions. Author: Namita Sharma, Senior Corporate Trainer at Koenig Solutions. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SSAS

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  • Some OBI EE Tricks and Tips in the Admin Tool By Gerry Langton

    - by hamsun
    How to set the log level from a Session variable Initialization block As we know it is normal to set the log level non-zero for a particular user when we wish to debug problems. However sometimes it is inconvenient to go into each user’s properties in the Admin tool and update the log level. So I am showing a method which allows the log level to be set for all users via a session initialization block. This is particularly useful for anyone wanting an alternative way to set the log level. The screen shots shown are using the OBIEE 11g SampleApp demo but are applicable to any environment. Open the appropriate rpd in on-line mode and navigate to Manage Variables. Select Session Initialization Blocks, right click in the white space and create a New Initialization Block. I called the Initialization block Set_Loglevel . Now click on ‘Edit Data Source’ to enter the SQL. Chose the ‘Use OBI EE Server’ option for the SQL. This means that the SQL provided must use tables which have been defined in the Physical layer of the RPD, and whilst there is no need to provide a connection pool you must work in On-Line mode. The SQL can access any of the RPD tables and is purely used to return a value of 2. The ‘Test’ button confirms that the SQL is valid. Next, click on the ‘Edit Data Target’ button to add the LOGLEVEL variable to the initialization block. Check the ‘Enable any user to set the value’ option so that this will work for any user. Click OK and the following message will display as LOGLEVEL is a system session variable: Click ‘Yes’. Click ‘OK’ to save the Initialization block. Then check in the On-LIne changes. To test that LOGLEVEL has been set, log in to OBIEE using an administrative login (e.g. weblogic) and reload server metadata, either from the Analysis editor or from Administration > Reload Files and Metadata link. Run a query then navigate to Administration > Manage Sessions and click ‘View Log’ for the query just issued (which should be approximately the last in the list). A log file should exist and with LOGLEVEL set to 2 should include both logical and physical sql. If more diagnostic information is required then set LOGLEVEL to a higher value. If logging is required only for a particular analysis then an alternative method can be used directly from the Analysis editor. Edit the analysis for which debugging is required and click on the Advanced tab. Scroll down to the Advanced SQL clauses section and enter the following in the Prefix box: SET VARIABLE LOGLEVEL = 2; Click the ‘Apply SQL’ button. The SET VARIABLE statement will now prefix the Analysis’s logical SQL. So that any time this analysis is run it will produce a log. You can find information about training for Oracle BI EE products here or in the OU Learning Paths. Please send me an email at [email protected] if you have any further questions. About the Author: Gerry Langton started at Siebel Systems in 1999 working as a technical instructor teaching both Siebel application development and also Siebel Analytics (which subsequently became Oracle BI EE). From 2006 Gerry has worked as Senior Principal Instructor within Oracle University specialising in Oracle BI EE, Oracle BI Publisher and Oracle Data Warehouse development for BI.

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  • Know your Data Lineage

    - by Simon Elliston Ball
    An academic paper without the footnotes isn’t an academic paper. Journalists wouldn’t base a news article on facts that they can’t verify. So why would anyone publish reports without being able to say where the data has come from and be confident of its quality, in other words, without knowing its lineage. (sometimes referred to as ‘provenance’ or ‘pedigree’) The number and variety of data sources, both traditional and new, increases inexorably. Data comes clean or dirty, processed or raw, unimpeachable or entirely fabricated. On its journey to our report, from its source, the data can travel through a network of interconnected pipes, passing through numerous distinct systems, each managed by different people. At each point along the pipeline, it can be changed, filtered, aggregated and combined. When the data finally emerges, how can we be sure that it is right? How can we be certain that no part of the data collection was based on incorrect assumptions, that key data points haven’t been left out, or that the sources are good? Even when we’re using data science to give us an approximate or probable answer, we cannot have any confidence in the results without confidence in the data from which it came. You need to know what has been done to your data, where it came from, and who is responsible for each stage of the analysis. This information represents your data lineage; it is your stack-trace. If you’re an analyst, suspicious of a number, it tells you why the number is there and how it got there. If you’re a developer, working on a pipeline, it provides the context you need to track down the bug. If you’re a manager, or an auditor, it lets you know the right things are being done. Lineage tracking is part of good data governance. Most audit and lineage systems require you to buy into their whole structure. If you are using Hadoop for your data storage and processing, then tools like Falcon allow you to track lineage, as long as you are using Falcon to write and run the pipeline. It can mean learning a new way of running your jobs (or using some sort of proxy), and even a distinct way of writing your queries. Other Hadoop tools provide a lot of operational and audit information, spread throughout the many logs produced by Hive, Sqoop, MapReduce and all the various moving parts that make up the eco-system. To get a full picture of what’s going on in your Hadoop system you need to capture both Falcon lineage and the data-exhaust of other tools that Falcon can’t orchestrate. However, the problem is bigger even that that. Often, Hadoop is just one piece in a larger processing workflow. The next step of the challenge is how you bind together the lineage metadata describing what happened before and after Hadoop, where ‘after’ could be  a data analysis environment like R, an application, or even directly into an end-user tool such as Tableau or Excel. One possibility is to push as much as you can of your key analytics into Hadoop, but would you give up the power, and familiarity of your existing tools in return for a reliable way of tracking lineage? Lineage and auditing should work consistently, automatically and quietly, allowing users to access their data with any tool they require to use. The real solution, therefore, is to create a consistent method by which to bring lineage data from these data various disparate sources into the data analysis platform that you use, rather than being forced to use the tool that manages the pipeline for the lineage and a different tool for the data analysis. The key is to keep your logs, keep your audit data, from every source, bring them together and use the data analysis tools to trace the paths from raw data to the answer that data analysis provides.

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  • Cooperative linux vs vm

    - by Rhythmic Algorithm
    What are the advantages / disadvantages of using cooperative linux like portable ubuntu for example compared to a qemu or any other virtual machine installation. Is one option notably faster than the other plus and other things that should be taken into consideration.

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  • How to stop RAID5 array while it is shown to be busy?

    - by RCola
    I have a raid5 array and need to stop it, but while trying to stop it getting error. # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sde1[3](F) sdc1[4](F) sdf1[2] sdd1[1] 2120320 blocks level 5, 32k chunk, algorithm 2 [3/2] [_UU] unused devices: <none> # mdadm --stop mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: No devices given. # mdadm --stop /dev/md0 mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: fail to stop array /dev/md0: Device or resource busy and # lsof | grep md0 md0_raid5 965 root cwd DIR 8,1 4096 2 / md0_raid5 965 root rtd DIR 8,1 4096 2 / md0_raid5 965 root txt unknown /proc/965/exe # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sde1[3](F) sdc1[4](F) sdf1[2] sdd1[1] 2120320 blocks level 5, 32k chunk, algorithm 2 [3/2] [_UU] # grep md0 /proc/mdstat md0 : active raid5 sde1[3](F) sdc1[4](F) sdf1[2] sdd1[1] # grep md0 /proc/partitions 9 0 2120320 md0 While booting, md1 is mounted ok but md0 failed for some unknown reason # dmesg | grep md[0-9] [ 4.399658] raid5: allocated 3179kB for md1 [ 4.400432] raid5: raid level 5 set md1 active with 3 out of 3 devices, algorithm 2 [ 4.400678] md1: detected capacity change from 0 to 2121793536 [ 4.403135] md1: unknown partition table [ 38.937932] Filesystem "md1": Disabling barriers, trial barrier write failed [ 38.941969] XFS mounting filesystem md1 [ 41.058808] Ending clean XFS mount for filesystem: md1 [ 46.325684] raid5: allocated 3179kB for md0 [ 46.327103] raid5: raid level 5 set md0 active with 2 out of 3 devices, algorithm 2 [ 46.330620] md0: detected capacity change from 0 to 2171207680 [ 46.335598] md0: unknown partition table [ 46.410195] md: recovery of RAID array md0 [ 117.970104] md: md0: recovery done. # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sde1[0] sdf1[2] sdd1[1] 2120320 blocks level 5, 32k chunk, algorithm 2 [3/3] [UUU] md1 : active raid5 sdc2[0] sdf2[2] sde2[3](S) sdd2[1] 2072064 blocks level 5, 128k chunk, algorithm 2 [3/3] [UUU]

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  • XNA running slow when making a texture

    - by Anthony
    I'm using XNA to test an image analysis algorithm for a robot. I made a simple 3D world that has a grass, a robot, and white lines (that are represent the course). The image analysis algorithm is a modification of the Hough line detection algorithm. I have the game render 2 camera views to a render target in memory. One camera is a top down view of the robot going around the course, and the second camera is the view from the robot's perspective as it moves along. I take the rendertarget of the robot camera and convert it to a Color[,] so that I can do image analysis on it. private Color[,] TextureTo2DArray(Texture2D texture, Color[] colors1D, Color[,] colors2D) { texture.GetData(colors1D); for (int x = 0; x < texture.Width; x++) { for (int y = 0; y < texture.Height; y++) { colors2D[x, y] = colors1D[x + (y * texture.Width)]; } } return colors2D; } I want to overlay the results of the image analysis on the robot camera view. The first part of the image analysis is finding the white pixels. When I find the white pixels I create a bool[,] array showing which pixels were white and which were black. Then I want to convert it back into a texture so that I can overlay on the robot view. When I try to create the new texture showing which ones pixels were white, then the game goes super slow (around 10 hz). Can you give me some pointers as to what to do to make the game go faster. If I comment out this algorithm, then it goes back up to 60 hz. private Texture2D GenerateTexturesFromBoolArray(bool[,] boolArray,Color[] colorMap, Texture2D textureToModify) { for(int i =0;i < screenWidth;i++) { for(int j =0;j<screenHeight;j++) { if (boolArray[i, j] == true) { colorMap[i+(j*screenWidth)] = Color.Red; } else { colorMap[i + (j * screenWidth)] = Color.Transparent; } } } textureToModify.SetData<Color>(colorMap); return textureToModify; } Each Time I run draw, I must set the texture to null, so that I can modify it. public override void Draw(GameTime gameTime) { Vector2 topRightVector = ((SimulationMain)Game).spriteRectangleManager.topRightVector; Vector2 scaleFactor = ((SimulationMain)Game).config.scaleFactorScreenSizeToWindow; this.spriteBatch.Begin(); // Start the 2D drawing this.spriteBatch.Draw(this.textureFindWhite, topRightVector, null, Color.White, 0, Vector2.Zero, scaleFactor, SpriteEffects.None, 0); this.spriteBatch.End(); // Stop drawing. GraphicsDevice.Textures[0] = null; } Thanks for the help, Anthony G.

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  • SQL SERVER – What is SSAS Tabular Data model and Why to use it – Part 2

    - by Pinal Dave
    In my last article, I talked about the basics of tabular data model and why use it. Then I demonstrated step by step creation of a basic tabular model project. In this part I’m going to throw some light on how to create measures and analyses in excel. If you look at the tabular project closely, you will notice that we have not defined any measure yet. So, in the first step we will define the measure first.  Open the solution and select the column you want to define as a measure. Then, click on the summation icon on the toolbar. You will see the aggregated results at the bottom of that column. You have also other choices as well like average, min, max, count and distinct count. After creating the required measures, we need to analyze our data in excel. To do this, click on the excel icon in the upper left corner of the toolbar. This will open your analysis in excel. Notice the pivot table field list here. I have highlighted the measures that we created in the earlier step. Now, we can use these measures in our analysis Now, we have to put the required fields in their respective places as column labels, row labels, Values and Report filter for analysis. See below snapshot for details, it shows region wise sales on a yearly basis You can even apply filters on the above analysis by placing the slicer field in report filter. In our example, we will take an English product name as a filter. You can use the filter as depicted in the below snapshot. Optionally, you can also use the slider to filter data more interactively. Further to improve our analysis, we can insert pivot charts That’s all for this time, in my next post I’m going to show in detail about how to create hierarchies, perspectives, KPI’s  and many more features. Author: Namita Sharma, Senior Corporate Trainer at Koenig Solutions. Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SSAS

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  • How to get compatibility between C# and SQL2k8 AES Encryption?

    - by Victor Rodrigues
    I have an AES encryption being made on two columns: one of these columns is stored at a SQL Server 2000 database; the other is stored at a SQL Server 2008 database. As the first column's database (2000) doesn't have native functionality for encryption / decryption, we've decided to do the cryptography logic at application level, with .NET classes, for both. But as the second column's database (2008) allow this kind of functionality, we'd like to make the data migration using the database functions to be faster, since the data migration in SQL 2k is much smaller than this second and it will last more than 50 hours because of being made at application level. My problem started at this point: using the same key, I didn't achieve the same result when encrypting a value, neither the same result size. Below we have the full logic in both sides.. Of course I'm not showing the key, but everything else is the same: private byte[] RijndaelEncrypt(byte[] clearData, byte[] Key) { var memoryStream = new MemoryStream(); Rijndael algorithm = Rijndael.Create(); algorithm.Key = Key; algorithm.IV = InitializationVector; var criptoStream = new CryptoStream(memoryStream, algorithm.CreateEncryptor(), CryptoStreamMode.Write); criptoStream.Write(clearData, 0, clearData.Length); criptoStream.Close(); byte[] encryptedData = memoryStream.ToArray(); return encryptedData; } private byte[] RijndaelDecrypt(byte[] cipherData, byte[] Key) { var memoryStream = new MemoryStream(); Rijndael algorithm = Rijndael.Create(); algorithm.Key = Key; algorithm.IV = InitializationVector; var criptoStream = new CryptoStream(memoryStream, algorithm.CreateDecryptor(), CryptoStreamMode.Write); criptoStream.Write(cipherData, 0, cipherData.Length); criptoStream.Close(); byte[] decryptedData = memoryStream.ToArray(); return decryptedData; } This is the SQL Code sample: open symmetric key columnKey decryption by password = N'{pwd!!i_ll_not_show_it_here}' declare @enc varchar(max) set @enc = dbo.VarBinarytoBase64(EncryptByKey(Key_GUID('columnKey'), 'blablabla')) select LEN(@enc), @enc This varbinaryToBase64 is a tested sql function we use to convert varbinary to the same format we use to store strings in the .net application. The result in C# is: eg0wgTeR3noWYgvdmpzTKijkdtTsdvnvKzh+uhyN3Lo= The same result in SQL2k8 is: AI0zI7D77EmqgTQrdgMBHAEAAACyACXb+P3HvctA0yBduAuwPS4Ah3AB4Dbdj2KBGC1Dk4b8GEbtXs5fINzvusp8FRBknF15Br2xI1CqP0Qb/M4w I just didn't get yet what I'm doing wrong. Do you have any ideas? EDIT: One point I think is crucial: I have one Initialization Vector at my C# code, 16 bytes. This IV is not set at SQL symmetric key, could I do this? But even not filling the IV in C#, I get very different results, both in content and length.

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  • VS 2012 Code Review &ndash; Before Check In OR After Check In?

    - by Tarun Arora
    “Is Code Review Important and Effective?” There is a consensus across the industry that code review is an effective and practical way to collar code inconsistency and possible defects early in the software development life cycle. Among others some of the advantages of code reviews are, Bugs are found faster Forces developers to write readable code (code that can be read without explanation or introduction!) Optimization methods/tricks/productive programs spread faster Programmers as specialists "evolve" faster It's fun “Code review is systematic examination (often known as peer review) of computer source code. It is intended to find and fix mistakes overlooked in the initial development phase, improving both the overall quality of software and the developers' skills. Reviews are done in various forms such as pair programming, informal walkthroughs, and formal inspections.” Wikipedia No where does the definition mention whether its better to review code before the code has been committed to version control or after the commit has been performed. No matter which side you favour, Visual Studio 2012 allows you to request for a code review both before check in and also request for a review after check in. Let’s weigh the pros and cons of the approaches independently. Code Review Before Check In or Code Review After Check In? Approach 1 – Code Review before Check in Developer completes the code and feels the code quality is appropriate for check in to TFS. The developer raises a code review request to have a second pair of eyes validate if the code abides to the recommended best practices, will not result in any defects due to common coding mistakes and whether any optimizations can be made to improve the code quality.                                             Image 1 – code review before check in Pros Everything that gets committed to source control is reviewed. Minimizes the chances of smelly code making its way into the code base. Decreases the cost of fixing bugs, remember, the earlier you find them, the lesser the pain in fixing them. Cons Development Code Freeze – Since the changes aren’t in the source control yet. Further development can only be done off-line. The changes have not been through a CI build, hard to say whether the code abides to all build quality standards. Inconsistent! Cumbersome to track the actual code review process.  Not every change to the code base is worth reviewing, a lot of effort is invested for very little gain. Approach 2 – Code Review after Check in Developer checks in, random code reviews are performed on the checked in code.                                                      Image 2 – Code review after check in Pros The code has already passed the CI build and run through any code analysis plug ins you may have running on the build server. Instruct the developer to ensure ZERO fx cop, style cop and static code analysis before check in. Code is cleaner and smell free even before the code review. No Offline development, developers can continue to develop against the source control. Cons Bad code can easily make its way into the code base. Since the review take place much later in the cycle, the cost of fixing issues can prove to be much higher. Approach 3 – Hybrid Approach The community advocates a more hybrid approach, a blend of tooling and human accountability quotient.                                                               Image 3 – Hybrid Approach 1. Code review high impact check ins. It is not possible to review everything, by setting up code review check in policies you can end up slowing your team. More over, the code that you are reviewing before check in hasn't even been through a green CI build either. 2. Tooling. Let the tooling work for you. By running static analysis, fx cop, style cop and other plug ins on the build agent, you can identify the real issues that in my opinion can't possibly be identified using human reviews. Configure the tooling to report back top 10 issues every day. Mandate the manual code review of individuals who keep making it to this list of shame more often. 3. During Merge. I would prefer eliminating some of the other code issues during merge from Main branch to the release branch. In a scrum project this is still easier because cheery picking the merges is a possibility and the size of code being reviewed is still limited. Let the tooling work for you, if some one breaks the CI build often, put them on a gated check in build course until you see improvement. If some one appears on the top 10 list of shame generated via the build then ensure that all their code is reviewed till you see improvement. At the end of the day, the goal is to ensure that the code being delivered is top quality. By enforcing a code review before any check in, you force the developer to work offline or stay put till the review is complete. What do the experts say? So I asked a few expects what they thought of “Code Review quality gate before Checking in code?" Terje Sandstrom | Microsoft ALM MVP You mean a review quality gate BEFORE checking in code????? That would mean a lot of code staying either local or in shelvesets, and not even been through a CI build, and a green CI build being the main criteria for going further, f.e. to the review state. I would not like code laying around with no checkin’s. Having a requirement that code is checked in small pieces, 4-8 hours work max, and AT LEAST daily checkins, a manual code review comes second down the lane. I would expect review quality gates to happen before merging back to main, or before merging to release.  But that would all be on checked-in code.  Branching is absolutely one way to ease the pain.   Another way we are using is automatic quality builds, running metrics, coverage, static code analysis.  Unfortunately it takes some time, would be great to be on CI’s – but…., so it’s done scheduled every night. Based on this we get, among other stuff,  top 10 lists of suspicious code, which is then subjected to reviews.  If a person seems to be very popular on these top 10 lists, we subject every check in from that person to a review for a period. That normally helps.   None of the clients I have can afford to have every checkin reviewed, so we need to find ways around it. I don’t disagree with the nicety of having all the code reviewed, but I find it hard to find those resources in today’s enterprises. David V. Corbin | Visual Studio ALM Ranger I tend to agree with both sides. I hate having code that is not checked in, but at the same time hate having “bad” code in the repository. I have found that branching is one approach to solving this dilemma. Code is checked into the private/feature branch before the review, but is not merged over to the “official” branch until after the review. I advocate both, depending on circumstance (especially team dynamics)   - The “pre-checkin” is usually for elements that may impact the project as a whole. Think of it as another “gate” along with passing unit tests. - The “post-checkin” may very well not be at the changeset level, but correlates to a review at the “user story” level.   Again, this depends on team dynamics in play…. Robert MacLean | Microsoft ALM MVP I do not think there is no right answer for the industry as a whole. In short the question is why do you do reviews? Your question implies risk mitigation, so in low risk areas you can get away with it after check in while in high risk you need to do it before check in. An example is those new to a team or juniors need it much earlier (maybe that is before checkin, maybe that is soon after) than seniors who have shipped twenty sprints on the team. Abhimanyu Singhal | Visual Studio ALM Ranger Depends on per scenario basis. We recommend post check-in reviews when: 1. We don't want to block other checks and processes on manual code reviews. Manual reviews take time, and some pieces may not require manual reviews at all. 2. We need to trace all changes and track history. 3. We have a code promotion strategy/process in place. For risk mitigation, post checkin code can be promoted to Accepted branches. Or can be rejected. Pre Checkin Reviews are used when 1. There is a high risk factor associated 2. Reviewers are generally (most of times) have immediate availability. 3. Team does not have strict tracking needs. Simply speaking, no single process fits all scenarios. You need to select what works best for your team/project. Thomas Schissler | Visual Studio ALM Ranger This is an interesting discussion, I’m right now discussing details about executing code reviews with my teams. I see and understand the aspects you brought in, but there is another side as well, I’d like to point out. 1.) If you do reviews per check in this is not very practical as a hard rule because this will disturb the flow of the team very often or it will lead to reduce the checkin frequency of the devs which I would not accept. 2.) If you do later reviews, for example if you review PBIs, it is not easy to find out which code you should review. Either you review all changesets associate with the PBI, but then you might review code which has been changed with a later checkin and the dev maybe has already fixed the issue. Or you review the diff of the latest changeset of the PBI with the first but then you might also review changes of other PBIs. Jakob Leander | Sr. Director, Avanade In my experience, manual code review: 1. Does not get done and at the very least does not get redone after changes (regardless of intentions at start of project) 2. When a project actually do it, they often do not do it right away = errors pile up 3. Requires a lot of time discussing/defining the standard and for the team to learn it However code review is very important since e.g. even small memory leaks in a high volume web solution have big consequences In the last years I have advocated following approach for code review - Architects up front do “at least one best practice example” of each type of component and tell the team. Copy from this one. This should include error handling, logging, security etc. - Dev lead on project continuously browse code to validate that the best practices are used. Especially that patterns etc. are not broken. You can do this formally after each sprint/iteration if you want. Once this is validated it is unlikely to “go bad” even during later code changes Agree with customer to rely on static code analysis from Visual Studio as the one and only coding standard. This has HUUGE benefits - You can easily tweak to reach the level you desire together with customer - It is easy to measure for both developers/management - It is 100% consistent across code base - It gets validated all the time so you never end up getting hammered by a customer review in the end - It is easy to tell the developer that you do not want code back unless it has zero errors = minimize communication You need to track this at least during nightly builds and make sure team sees total # issues. Do not allow #issues it to grow uncontrolled. On the project I run I require code analysis to have run on code before checkin (checkin rule). This means -  You have to have clean compile (or CA wont run) so this is extra benefit = very few broken builds - You can change a few of the rules to compile as errors instead of warnings. I often do this for “missing dispose” issues which you REALLY do not want in your app Tip: Place your custom CA rules files as part of solution. That  way it works when you do branching etc. (path to CA file is relative in VS) Some may argue that CA is not as good as manual inspection. But since manual inspection in reality suffers from the 3 issues in start it is IMO a MUCH better (and much cheaper) approach from helicopter perspective Tirthankar Dutta | Director, Avanade I think code review should be run both before and after check ins. There are some code metrics that are meant to be run on the entire codebase … Also, especially on multi-site projects, one should strive to architect in a way that lets men manage the framework while boys write the repetitive code… scales very well with the need to review less by containment and imposing architectural restrictions to emphasise the design. Bruno Capuano | Microsoft ALM MVP For code reviews (means peer reviews) in distributed team I use http://www.vsanywhere.com/default.aspx  David Jobling | Global Sr. Director, Avanade Peer review is the only way to scale and its a great practice for all in the team to learn to perform and accept. In my experience you soon learn who's code to watch more than others and tune the attention. Mikkel Toudal Kristiansen | Manager, Avanade If you have several branches in your code base, you will need to merge often. This requires manual merging, when a file has been changed in both branches. It offers a good opportunity to actually review to changed code. So my advice is: Merging between branches should be done as often as possible, it should be done by a senior developer, and he/she should perform a full code review of the code being merged. As for detecting architectural smells and code smells creeping into the code base, one really good third party tools exist: Ndepend (http://www.ndepend.com/, for static code analysis of the current state of the code base). You could also consider adding StyleCop to the solution. Jesse Houwing | Visual Studio ALM Ranger I gave a presentation on this subject on the TechDays conference in NL last year. See my presentation and slides here (talk in Dutch, but English presentation): http://blog.jessehouwing.nl/2012/03/did-you-miss-my-techdaysnl-talk-on-code.html  I’d like to add a few more points: - Before/After checking is mostly a trust issue. If you have a team that does diligent peer reviews and regularly talk/sit together or peer review, there’s no need to enforce a before-checkin policy. The peer peer-programming and regular feedback during development can take care of most of the review requirements as long as the team isn’t under stress. - Under stress, enforce pre-checkin reviews, it might sound strange, if you’re already under time or budgetary constraints, but it is under such conditions most real issues start to be created or pile up. - Use tools to catch most common errors, Code Analysis/FxCop was already mentioned. HP Fortify, Resharper, Coderush etc can help you there. There are also a lot of 3rd party rules you can add to Code Analysis. I’ve written a few myself (http://fccopcontrib.codeplex.com) and various teams from Microsoft have added their own rules (MSOCAF for SharePoint, WSSF for WCF). For common errors that keep cropping up, see if you can define a rule. It’s much easier. But more importantly make sure you have a good help page explaining *WHY* it's wrong. If you have small feature or developer branches/shelvesets, you might want to review pre-merge. It’s still better to do peer reviews and peer programming, but the most important thing is that bad quality code doesn’t make it into the important branch. So my philosophy: - Use tooling as much as possible. - Make sure the team understands the tooling and the importance of the things it flags. It’s too easy to just click suppress all to ignore the warnings. - Under stress, tighten process, it’s under stress that the problems of late reviews will really surface - Most importantly if you do reviews do them as early as possible, but never later than needed. In other words, pre-checkin/post checking doesn’t really matter, as long as the review is done before the code is released. It’ll just be much more expensive to fix any review outcomes the later you find them. --- I would love to hear what you think!

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  • How to collect the performance data of a server during an unreachable/down period using Nagios?

    - by gsc-frank
    Some time services and host stop responding due to a poor server performance. I mean, if for some reason (could be lot of concurrency services access, a expensive backup execution on the server or whatever that consume tons of server resources) a server performance is very degraded, that could lead that the server isn't capable to establish any "normal network communication" (without trigger whatever standards timeouts defined for such communication). Knowing host's performance data (cpu, memory, ...) in case of available during that period (host is not down and despite of its performance degradation still allow plugins collect performance data) could be very useful for sysadmin to try to determine what cause the problem, or at least, if the host performance was good and don't interfered at all in the host/service down. This problem could be solved using remote active (NRPE) or remote passive (NSCA) if such remote solutions could store (buffered) perf data to be send to central Nagios server when host performance or network outage allow it. I read the doc of both solutions and can't find any reference to such buffer mechanism neither what happened in case that NSCA can't reach Nagios server. Any idea of how solve this lack of info? so useful for forensic analysis. EDIT: My questions isn about which tools I can use to debug perf problems or gather perf data to analysis, but is about how collect (using Nagios) host perf data even during a network outage for its posterior analysis (kind of forensic analysis). The idea is integrate such data to Nagios graphers like pnp4nagios and NagiosGrapther. I know that I could install tools like Cacti in each of my host, and have a kind of performance data collection redundancy, but I really want avoid that and try to solve all perf analysis requirements with one tools: Nagios

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  • SQLAuthority News – Microsoft SQL Server 2008 R2 – PowerPivot for Microsoft Excel 2010

    - by pinaldave
    Microsoft has really and truly created some buzz for PowerPivot. I have been asked to show the demo of Powerpivot in recent time even when I am doing relational database training. Attached is the few details where everyone can download PowerPivot and use the same. Microsoft SQL Server 2008 R2 – PowerPivot for Microsoft Excel 2010 – RTM Microsoft® PowerPivot for Microsoft® Excel 2010 provides ground-breaking technology, such as fast manipulation of large data sets (often millions of rows), streamlined integration of data, and the ability to effortlessly share your analysis through Microsoft® SharePoint 2010. Microsoft PowerPivot for Excel 2010 Samples Microsoft® PowerPivot for Microsoft® Excel 2010 provides ground-breaking technology, such as fast manipulation of large data sets (often millions of rows), streamlined integration of data, and the ability to effortlessly share your analysis through Microsoft® SharePoint 2010. Download examples of the types of reports you can create. Microsoft PowerPivot for Excel 2010 Data Analysis Expressions Sample version 1.0 Microsoft® PowerPivot for Microsoft® Excel 2010 provides ground-breaking technology, such as fast manipulation of large data sets (often millions of rows), streamlined integration of data, and the ability to effortlessly share your analysis through Microsoft® SharePoint 2010. Download this PowerPivot workbook to learn more about DAX calculations. Note: The brief description below the download link is taken from respective download page. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Documentation in Oracle Retail Analytics, Release 13.3

    - by Oracle Retail Documentation Team
    The 13.3 Release of Oracle Retail Analytics is now available on the Oracle Software Delivery Cloud and from My Oracle Support. The Oracle Retail Analytics 13.3 release introduced significant new functionality with its new Customer Analytics module. The Customer Analytics module enables you to perform retail analysis of customers and customer segments. Market basket analysis (part of the Customer Analytics module) provides insight into which products have strong affinity with one another. Customer behavior information is obtained from mining sales transaction history, and it is correlated with customer segment attributes to inform promotion strategies. The ability to understand market basket affinities allows marketers to calculate, monitor, and build promotion strategies based on critical metrics such as customer profitability. Highlighted End User Documentation Updates With the addition of Oracle Retail Customer Analytics, the documentation set addresses both modules under the single umbrella name of Oracle Retail Analytics. Note, however, that the modules, Oracle Retail Merchandising Analytics and Oracle Retail Customer Analytics, are licensed separately. To accommodate new functionality, the Retail Analytics suite of documentation has been updated in the following areas, among others: The User Guide has been updated with an overview of Customer Analytics. It also contains a list of metrics associated with Customer Analytics. The Operations Guide provides details on Market Basket Analysis as well as an updated list of APIs. The program reference list now also details the module (Merchandising Analytics or Customer Analytics) to which each program applies. The Data Model was updated to include new information related to Customer Analytics, and a new section, Market Basket Analysis Module, was added to the document with its own entity relationship diagrams and data definitions. List of Documents The following documents are included in Oracle Retail Analytics 13.3: Oracle Retail Analytics Release Notes Oracle Retail Analytics Installation Guide Oracle Retail Analytics User Guide Oracle Retail Analytics Implementation Guide Oracle Retail Analytics Operations Guide Oracle Retail Analytics Data Model

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