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  • Is it considered poor programming to do this with xna components?

    - by Rob
    I created my own Menu System that is event driven. In order to have a loading screen and multithreaded loading to work, I devised this sort of implementation: //Let's check if the game is done loading. if (_game != null) { _gameLoaded = _game.DoneLoading; } //This means the game is loading still, //therefore the loading screen should be active. if (!_gameLoaded && _gameActive) { _gameScreenList[2].UpdateMenu(); } //The loading screen was selected. if (_gameScreenList[2].CurrentState == GameScreen.State.Shown && !_gameActive) { Components.Add(_game = new ParadoxGame(this)); _game.Initialize(); //Initializes the Game so that the loading can begin. _gameActive = true; } In the XNA Game Component that contains the actual game, in the LoadContent method I simply created a new Thread that calls another method ThreadLoad that has all the actual loading. I also have a boolean variable called DoneLoading in the XNA Game Component that is set to true at the end of the ThreadLoad. I am wondering if this is a poor implementation.

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  • Is self learning Computer Science/programming over a college degree worth it? [on hold]

    - by user106576
    I am currently in college and I just want to skip to learning and gaining experience in what I came here to do, but unfortunately the first two years of college is general classes that everyone takes. I have a couple of friends that are also in Computer Science and we were planning on starting a small company/self employment. Would dropping out and gaining experience and a portfolio qualify for smaller companies if I look for a job there? What programs should I learn, and which ones should I learn before others to better understand the programs that are harder?

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  • Why is cleverness considered harmful in programming by some people?

    - by Larry Coleman
    I've noticed a lot of questions lately relating to different abstraction techniques, and answers saying basically that the techniques in question are "too clever." I would think that part of our jobs as programmers is to determine the best solutions to the problems we are given to solve, and cleverness is helpful in doing that. So my question is: are the people who think certain abstraction techniques are too clever opposed to cleverness per se, or is there some other reason for the objection? EDIT: This parser combinator is an example of what I would consider to be clever code. I downloaded this and looked it over for about half an hour. Then I stepped through the macro expansion on paper and saw the light. Now that I understand it, it seems much more elegant than the Haskell parser combinator.

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  • Contract Programming - Deposit % and Payment Methods? Any advice is appreciated

    - by Rick
    I'm pretty new to doing contract work and finally landed a decent paying project. The guy actually offered to put down a deposit and I'm just wondering what percentage I should consider asking for. I was thinking around 25% since its not a terribly large project (only about 20 hours). Also, I can't use PayPal (have had a terrible experience with them freezing funds for no good reason) so I'm wondering if anyone can suggest other methods for the client to send the deposit / payment. I want to make it as easy as possible for them.. thanks for any advice

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  • Two book reviews

    - by bipinjoshi
    I recently reviewed two books -  Programming Microsoft ASP.NET MVC, 2nd Edition and Programming Entity Framework - Code First. Here are the links to the complete reviews:Programming Microsoft ASP.NET MVC, 2nd Edition http://www.bipinjoshi.net/articles/43fcbd2d-2d44-4df7-9cf1-492eb63bc31a.aspx Programming Entity Framework - Code Firsthttp://www.bipinjoshi.net/articles/5e5ea033-a57e-436b-9b4c-e3638e8260b6.aspx  

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  • How to apply Data Oriented Design with Object Oriented Programming?

    - by Pombal
    Hi. I've read lots of articles about DOD and I understand it but I can't design an Object Oriented system with DOD in mind, I think my OOP education is blocking me. How should I think to mix the two? The objective is to have a nice OO interface while using DOD behind the scenes. I saw this too but didn't help much: http://stackoverflow.com/questions/3872354/how-to-apply-dop-and-keep-a-nice-user-interface

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  • How to Load Oracle Tables From Hadoop Tutorial (Part 5 - Leveraging Parallelism in OSCH)

    - by Bob Hanckel
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Using OSCH: Beyond Hello World In the previous post we discussed a “Hello World” example for OSCH focusing on the mechanics of getting a toy end-to-end example working. In this post we are going to talk about how to make it work for big data loads. We will explain how to optimize an OSCH external table for load, paying particular attention to Oracle’s DOP (degree of parallelism), the number of external table location files we use, and the number of HDFS files that make up the payload. We will provide some rules that serve as best practices when using OSCH. The assumption is that you have read the previous post and have some end to end OSCH external tables working and now you want to ramp up the size of the loads. Using OSCH External Tables for Access and Loading OSCH external tables are no different from any other Oracle external tables.  They can be used to access HDFS content using Oracle SQL: SELECT * FROM my_hdfs_external_table; or use the same SQL access to load a table in Oracle. INSERT INTO my_oracle_table SELECT * FROM my_hdfs_external_table; To speed up the load time, you will want to control the degree of parallelism (i.e. DOP) and add two SQL hints. ALTER SESSION FORCE PARALLEL DML PARALLEL  8; ALTER SESSION FORCE PARALLEL QUERY PARALLEL 8; INSERT /*+ append pq_distribute(my_oracle_table, none) */ INTO my_oracle_table SELECT * FROM my_hdfs_external_table; There are various ways of either hinting at what level of DOP you want to use.  The ALTER SESSION statements above force the issue assuming you (the user of the session) are allowed to assert the DOP (more on that in the next section).  Alternatively you could embed additional parallel hints directly into the INSERT and SELECT clause respectively. /*+ parallel(my_oracle_table,8) *//*+ parallel(my_hdfs_external_table,8) */ Note that the "append" hint lets you load a target table by reserving space above a given "high watermark" in storage and uses Direct Path load.  In other doesn't try to fill blocks that are already allocated and partially filled. It uses unallocated blocks.  It is an optimized way of loading a table without incurring the typical resource overhead associated with run-of-the-mill inserts.  The "pq_distribute" hint in this context unifies the INSERT and SELECT operators to make data flow during a load more efficient. Finally your target Oracle table should be defined with "NOLOGGING" and "PARALLEL" attributes.   The combination of the "NOLOGGING" and use of the "append" hint disables REDO logging, and its overhead.  The "PARALLEL" clause tells Oracle to try to use parallel execution when operating on the target table. Determine Your DOP It might feel natural to build your datasets in Hadoop, then afterwards figure out how to tune the OSCH external table definition, but you should start backwards. You should focus on Oracle database, specifically the DOP you want to use when loading (or accessing) HDFS content using external tables. The DOP in Oracle controls how many PQ slaves are launched in parallel when executing an external table. Typically the DOP is something you want to Oracle to control transparently, but for loading content from Hadoop with OSCH, it's something that you will want to control. Oracle computes the maximum DOP that can be used by an Oracle user. The maximum value that can be assigned is an integer value typically equal to the number of CPUs on your Oracle instances, times the number of cores per CPU, times the number of Oracle instances. For example, suppose you have a RAC environment with 2 Oracle instances. And suppose that each system has 2 CPUs with 32 cores. The maximum DOP would be 128 (i.e. 2*2*32). In point of fact if you are running on a production system, the maximum DOP you are allowed to use will be restricted by the Oracle DBA. This is because using a system maximum DOP can subsume all system resources on Oracle and starve anything else that is executing. Obviously on a production system where resources need to be shared 24x7, this can’t be allowed to happen. The use cases for being able to run OSCH with a maximum DOP are when you have exclusive access to all the resources on an Oracle system. This can be in situations when your are first seeding tables in a new Oracle database, or there is a time where normal activity in the production database can be safely taken off-line for a few hours to free up resources for a big incremental load. Using OSCH on high end machines (specifically Oracle Exadata and Oracle BDA cabled with Infiniband), this mode of operation can load up to 15TB per hour. The bottom line is that you should first figure out what DOP you will be allowed to run with by talking to the DBAs who manage the production system. You then use that number to derive the number of location files, and (optionally) the number of HDFS data files that you want to generate, assuming that is flexible. Rule 1: Find out the maximum DOP you will be allowed to use with OSCH on the target Oracle system Determining the Number of Location Files Let’s assume that the DBA told you that your maximum DOP was 8. You want the number of location files in your external table to be big enough to utilize all 8 PQ slaves, and you want them to represent equally balanced workloads. Remember location files in OSCH are metadata lists of HDFS files and are created using OSCH’s External Table tool. They also represent the workload size given to an individual Oracle PQ slave (i.e. a PQ slave is given one location file to process at a time, and only it will process the contents of the location file.) Rule 2: The size of the workload of a single location file (and the PQ slave that processes it) is the sum of the content size of the HDFS files it lists For example, if a location file lists 5 HDFS files which are each 100GB in size, the workload size for that location file is 500GB. The number of location files that you generate is something you control by providing a number as input to OSCH’s External Table tool. Rule 3: The number of location files chosen should be a small multiple of the DOP Each location file represents one workload for one PQ slave. So the goal is to keep all slaves busy and try to give them equivalent workloads. Obviously if you run with a DOP of 8 but have 5 location files, only five PQ slaves will have something to do and the other three will have nothing to do and will quietly exit. If you run with 9 location files, then the PQ slaves will pick up the first 8 location files, and assuming they have equal work loads, will finish up about the same time. But the first PQ slave to finish its job will then be rescheduled to process the ninth location file, potentially doubling the end to end processing time. So for this DOP using 8, 16, or 32 location files would be a good idea. Determining the Number of HDFS Files Let’s start with the next rule and then explain it: Rule 4: The number of HDFS files should try to be a multiple of the number of location files and try to be relatively the same size In our running example, the DOP is 8. This means that the number of location files should be a small multiple of 8. Remember that each location file represents a list of unique HDFS files to load, and that the sum of the files listed in each location file is a workload for one Oracle PQ slave. The OSCH External Table tool will look in an HDFS directory for a set of HDFS files to load.  It will generate N number of location files (where N is the value you gave to the tool). It will then try to divvy up the HDFS files and do its best to make sure the workload across location files is as balanced as possible. (The tool uses a greedy algorithm that grabs the biggest HDFS file and delegates it to a particular location file. It then looks for the next biggest file and puts in some other location file, and so on). The tools ability to balance is reduced if HDFS file sizes are grossly out of balance or are too few. For example suppose my DOP is 8 and the number of location files is 8. Suppose I have only 8 HDFS files, where one file is 900GB and the others are 100GB. When the tool tries to balance the load it will be forced to put the singleton 900GB into one location file, and put each of the 100GB files in the 7 remaining location files. The load balance skew is 9 to 1. One PQ slave will be working overtime, while the slacker PQ slaves are off enjoying happy hour. If however the total payload (1600 GB) were broken up into smaller HDFS files, the OSCH External Table tool would have an easier time generating a list where each workload for each location file is relatively the same.  Applying Rule 4 above to our DOP of 8, we could divide the workload into160 files that were approximately 10 GB in size.  For this scenario the OSCH External Table tool would populate each location file with 20 HDFS file references, and all location files would have similar workloads (approximately 200GB per location file.) As a rule, when the OSCH External Table tool has to deal with more and smaller files it will be able to create more balanced loads. How small should HDFS files get? Not so small that the HDFS open and close file overhead starts having a substantial impact. For our performance test system (Exadata/BDA with Infiniband), I compared three OSCH loads of 1 TiB. One load had 128 HDFS files living in 64 location files where each HDFS file was about 8GB. I then did the same load with 12800 files where each HDFS file was about 80MB size. The end to end load time was virtually the same. However when I got ridiculously small (i.e. 128000 files at about 8MB per file), it started to make an impact and slow down the load time. What happens if you break rules 3 or 4 above? Nothing draconian, everything will still function. You just won’t be taking full advantage of the generous DOP that was allocated to you by your friendly DBA. The key point of the rules articulated above is this: if you know that HDFS content is ultimately going to be loaded into Oracle using OSCH, it makes sense to chop them up into the right number of files roughly the same size, derived from the DOP that you expect to use for loading. Next Steps So far we have talked about OLH and OSCH as alternative models for loading. That’s not quite the whole story. They can be used together in a way that provides for more efficient OSCH loads and allows one to be more flexible about scheduling on a Hadoop cluster and an Oracle Database to perform load operations. The next lesson will talk about Oracle Data Pump files generated by OLH, and loaded using OSCH. It will also outline the pros and cons of using various load methods.  This will be followed up with a final tutorial lesson focusing on how to optimize OLH and OSCH for use on Oracle's engineered systems: specifically Exadata and the BDA. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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  • What legal considerations do I need to have when programming?

    - by JustJohn
    Recently I worked with a group to create a logging system for tutoring labs to track Tutor hours, and usage of the labs. We had to change the design a fair amount to be in compliance with FERPA. My question stems from the curiosity that in my course of study there has never been a real mention of how people in this field have to deal with complying with the law in their work. So I would like to know how much programmers have to consider the law in the work they do.

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  • What are the technial and programming requirements for writing a stealth keylogger?

    - by user970533
    I'm planning to write/code one such stealth keylogger that would bypass detection by a certain antivirus. (I don't want to name the vendor as I know how good Google queries are against StackExchange websites). I don't want to just download any keylogger from internet and try to encode it to evade detection. Writing code myself I would have the ability to make changes as I go; obscuration on both high-level and low-level language. I like control too. It seems naive but is it true that keyloggers are a thing of the past, probably because of how effective AV's have become in detecting such programs? I want some nice points on how can one easily write a robust, effective key logger preferably for a Windows environment?

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  • What legal considerations do I need to have when programming?

    - by JustJohn
    Recently I worked with a group to create a logging system for tutoring labs to track Tutor hours, and usage of the labs. We had to change the design a fair amount to be in compliance with FERPA. My question stems from the curiosity that in my course of study there has never been a real mention of how people in this field have to deal with complying with the law in their work. So I would like to know how much programmers have to consider the law in the work they do.

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  • Linux OpenGL programming, should I use GLX or any other?

    - by pahnin
    I'm new to OpenGL and found that there are a lot of libraries to do that in C, and I also found that glx is most friendly with Linux X Server, I just want to do basic stuff, and I cannot find any tutorials for GLX. Is GLX a bad thing? I just want to do some small graphical things without installing many libraries and getting confused. Can anyone suggest me something which has tutorials and simple to compile? I found a link with an example with GLX and it worked perfect with no errors: anyone please suggest where I can find nice documentation or any better libraries.

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  • DOMDocument programming: a lot of little dilemmas, how to solve them?

    - by Peter Krauss
    I need elegance and performance: how to decide by the "best implementation" for each DOM algorithm that I face. This simple "DOMNodeList grouper" illustrate many little dilemmas: use iterator_to_array or "populate an array", when not all items need to be copied. use clone operator, cloneNode method or import method? use parentNode::method() or documentElement::method? (see here) first removeChild or first replaceChild, no avoids "side effects"? ... My position, today, is only "do an arbitrary choice and follow it in all implementations" (like a "Convention over configuration" principle)... But, there are another considerations? About performance, there are some article showing benchmarks? PS: this is a generic DOM question, any language (PHP, Javascript, Python, etc.) have the problem.

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  • C Programming arrays, I dont understand how I would go about making this program, If anyone can just guide me through the basic outline please :) [on hold]

    - by Rashmi Kohli
    Problem The temperature of a car engine has been measured, from real-world experiments, as shown in the table and graph below: Time (min) Temperature (oC) 0 20 1 36 2 61 3 68 4 77 5 110 Use linear regression to find the engine’s temperature at 1.5 minutes, 4.3 minutes, and any other time specified by the user. Background In engineering, many times we measure several data points in an experiment, but then we need to predict a value that we have not measured which lies between two measured values, such as the problem statement above. If the relation between the measured parameters seems to be roughly linear, then we can use linear regression to find the relationship between those parameters. In the graph of the problem statement above, the relation seems to be roughly linear. Hence, we can apply linear regression to the above problem. Assuming y {y0, y1, …yn-1} has a linear relation with x {x0, x1, … xn-1}, we can say that: y = mx+b where m and b can be found with linear regression as follows: For the problem in this lab, using linear regression gives us the following line (in blue) compared to the measured curve (in red). As you can see, there is usually a difference between the measured values and the estimated (predicted) values. What linear regression does is to minimize those differences and still give us a straight line (blue). Other methods, such as non-linear regression, are also possible to achieve higher accuracy and better curve fitting. Requirements Your program should first print the table of the temperatures similar to the way it’s printed in the problem statement. It should then calculate the temperature at minute 1.5 and 4.3 and show the answers to the user. Next, it should prompt the user to enter a time in minutes (or -1 to quit), and after reading the user’s specified time it should give the value of the engine’s temperature at that time. It should then go back to the prompt. Hints •Use a one dimensional array to store the temperature values given in the problem statement. •Use functions to separate tasks such as calculating m, calculating b, calculating the temperature at a given time, printing the prompt, etc. You can then give your algorithm as well as you pseudo code per function, as opposed to one large algorithm diagram or one large sequence of pseudo code.

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  • What is the historical basis of using Javascript in web programming?

    - by rd108
    I come from a scientific biology background where we also use Python a lot. Now that I've begun to start with Web development, I've consistently found myself wondering just why it is that JavaScript is the primary client-side language on the Web. Is JavaScript's predominance a historical accident or something else? Also, I'm curious if there are any hurdles to integrating Python into client-side scripting?

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  • What non-computer based programming tools do you consider invaluable? [closed]

    - by Schroedinger
    Possible Duplicate: What physical tools do you find useful to work as a programmer? I'm talking about things like whiteboards for process planning, paper for mapping out logic flows, particular books that you've found relevant, things in your workspace that help you think and process what you're working on and how to attack problems. I'm starting out in a corporate environment and want to have an understanding of what tools really work for other programmers to help them work through their problems and solutions.

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  • Are there good replacements for client-side java in web programming? [closed]

    - by varesa
    Now since the latest java exploit, and many others in the past, people are again recommended to get rid of java on their computers for good. I, as a java web applications developer, am think about possible alternatives. Many seem to have gotten rid of java, so I would not like to develop for an environmet, that users do not have on their computers, and that they are not willing to install for security reasons. Are there any other real options that HTML5 + JS? (Don't take me wrong about not wanting HTML5+JS, I just want to know the options)

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  • Is it correct to refer to a performing programming assignments as a "computer labs"?

    - by Nick Rosencrantz
    Can we say that developing an algorithm is a "laboration"? Are these "labs"? At engineering performing an exercise or an assignement is refered to as "labs" but are those "labs" when in fact it is mainly software problem solving pretty much like numeric methods in math which are not "labs". When studying engineering such as electrical engineering or physics you might do a "laser lab" or a "chemical laboration" if you study chemical engineering for instance. How do you define "lab"? Just performing something experimental? This is sort of double meaning also the physical environment at universities which we call "computer labs" that in fact are just rooms with computers.

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  • What is ethical/unethical while seeking help on the web with programming assignments?

    - by HelpNeeder
    I have used the web and Stack Overflow extensively during the past month or so in creating my final project for my C# class. I have used so much code that I didn't write myself that I feel I am being unethical by not giving proper credit to the people who helped me; or the websites that have provided excellent examples. Is it unethical to publish work which was created by me, even though its hardest problems were solved by other people? Should I credit these people for helping me with my assignment? Or the web sites which provided examples?

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  • What personal milestones can you use to measure growth in your programming abilities?

    - by GWLlosa
    How can you determine objectively, over time, that you are getting any better at producing code? For example, I may sit here and feel that "I know <language> now, and I use <technique> now, so I must be better." But this does not account for my own bias, or the fact that I may be getting better at a slower rate than intended, or I may actually suck at <technique> and not realize it. What methods are available for one to objectively rate one's own abilities? What about to objectively compare them to their peer groups?

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  • How to be a pro in several programming languages? [on hold]

    - by trerums
    I love PHP and C# languages and i want to be excellent in both. I like to develop PHP applications using MySQL, Nginx, Memcached and so on technologies. I also like ASP.NET MVC stack and think it's great tools. But each technology requires a lot of time to master it. The same is true for C# web stack - there is a huge amount of things to be mastered like Azure, LINQ, Entity Framework ets. Mastering PHP means knowing how it works under the hood. Mastering C# means knowing CLR implementations on a deep level, knowing MSIL etc/ Where to get time for all this? Maybe this is "jack of all trades"? What can you advice?

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