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• select i th smallest element from array

  - by davit-datuashvili

  i have divide and conqurer method to find i th smalles element from array here is code public class rand_select{ public static int Rand_partition( int a[],int p,int q,int i){ //smallest in a[p..q] if ( p==q) return a[p]; int r=partition (a,p,q); int k=r-p+1; if (i==k) return a[r]; if (i<k){ return Rand_partition(a,p,r-1,i); } return Rand_partition(a,r-1,q,i-k); } public static void main(String[]args){ int a[]=new int []{6,10,13,15,8,3,2,12}; System.out.println(Rand_partition(a,0,a.length-1,7)); } public static int partition(int a[],int p,int q){ int m=a[0]; while ( p<q){ while (p<q && a[p++] <m){ p++; } while (q>p && a[q--]>m){ q--; } int t=a[p]; a[p]=a[q]; a[q]=t; } int k=0; for (int i=0;i<a.length;i++){ if ( a[i]==m){ k=i; } } return k; } } but here is problem java.lang.ArrayIndexOutOfBoundsException please help me

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• Too many columns to index - use mySQL Partitions?

  - by Christopher Padfield

  We have an application with a table with 20+ columns that are all searchable. Building indexes for all these columns would make write queries very slow; and any really useful index would often have to be across multiple columns increasing the number of indexes needed. However, for 95% of these searches, only a small subset of those rows need to be searched upon, and quite a small number - say 50,000 rows. So, we have considered using mySQL Partition tables - having a column that is basically isActive which is what we divide the two partitions by. Most search queries would be run with isActive=1. Most queries would then be run against the small 50,000 row partition and be quick without other indexes. Only issue is the rows where isActive=1 is not fixed; i.e. it's not based on the date of the row or anything fixed like that; we will need to update isActive based on use of the data in that row. As I understand it that is no problem though; the data would just be moved from one partition to another during the UPDATE query. We do have a PK on id for the row though; and I am not sure if this is a problem; the manual seemed to suggest the partition had to be based on any primary keys. This would be a huge problem for us because the primary key ID has no basis on whether the row isActive.

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• How can I compare the performance of log() and fp division in C++?

  - by Ventzi Zhechev

  Hi, I’m using a log-based class in C++ to store very small floating-point values (as the values otherwise go beyond the scope of double). As I’m performing a large number of multiplications, this has the added benefit of converting the multiplications to sums. However, at a certain point in my algorithm, I need to divide a standard double value by an integer value and than do a *= to a log-based value. I have overloaded the *= operator for my log-based class and the right-hand side value is first converted to a log-based value by running log() and than added to the left-hand side value. Thus the operations actually performed are floating-point division, log() and floating-point summation. My question whether it would be faster to first convert the denominator to a log-based value, which would replace the floating-point division with floating-point subtraction, yielding the following chain of operations: twice log(), floating-point subtraction, floating-point summation. In the end, this boils down to whether floating-point division is faster or slower than log(). I suspect that a common answer would be that this is compiler and architecture dependent, so I’ll say that I use gcc 4.2 from Apple on darwin 10.3.0. Still, I hope to get an answer with a general remark on the speed of these two operators and/or an idea on how to measure the difference myself, as there might be more going on here, e.g. executing the constructors that do the type conversion etc. Cheers!

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• Handling text menu in Python

  - by PulpFiction

  Hi all. I am trying to create a text based menu in Python. Here is the code: #!/usr/bin/env python def testcaseOutput(): print '1. Add. 2. Subtract. 3. Divide. 4. Multiply' try: answer = int(raw_input('Enter a value (1 - 4) >. ')) except ValueError: print 'Invalid input. Enter a value between 1 -4 .' testcaseOutput() if answer in range(1, 5): return answer else: print 'Invalid input. Enter a value between 1 - 4.' testcaseOutput() My question: When the user enters an invalid input, i.e. not a number, I want this function to get called again. So I used the recursive approach which I think is bad design. I use that approach again in the if answer in range(1, 5). Is there any other way to handle this? I need the prompt called again when there is an invalid input. Also, is there any way I can club the two constraints: check whether input is a number and check whether the number is in the range(1,5) together? As you can see, I am checking that individually.

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• Copy existing XML, duplicate element and modify

  - by Robert

  Hi, I have a tricky XSL problem at the moment. I need to copy the existing XML, copy a certain element (plus its child elements) and modify the value of two child-elements. The modifications are: divide value of the 'value' element by 110 and edit the value of the 'type' element from 'normal' to 'discount'. This is currently what I have: Current XML: <dataset> <data> <prices> <price> <value>50.00</value> <type>normal</type> </price> </prices> </data> </dataset> Expected result <dataset> <data> <prices> <price> <value>50.00</value> <type>normal</type> </price> <price> <value>45.00</value> <type>discount</type> </price> </prices> </data> </dataset> Any takers? I've gotten as far as copying the desired 'price' element using copy-of, but I'm stuck as to how to modify it next.

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• What is the proper way to wait a script loaded completely before another

  - by FatDogMark

  I am making a website that is divided by several sections <div id='section-1' class='section'>web content</div> <div id='section-2' class='section'>web content</div> I have like ten sections on my webpage ,each sections height is set to the user window height when document is ready by javascript $('.section').height($(window).height()); Some effects like slideshows on my webpage require the calculated height of the section in order to work properly. Therefore I always use something like this at document ready as a solution. setTimeout(startslideshow,1000); setTimeout(startanimations,1000); ...etc To make sure the section height is the user window height before the slideshow's code start because the sections cannot change to user window height instantly once the webpage loaded will generate serious problems in my slideshow code,like wrong calculated positions. Therefore there will be a situation that's after the page loaded, there will be about a second everything is messed up,before everything can works properly, how could I avoid that being seen by the user? I tried to $(document).hide(),or $('html,body').hide(), then fade in after a second,but I get other weird problems, especially on ipad,my fixed position top navigation bar will always become 'not fixed' while user is scrolling. As I am a self-learner, I afraid my method is not typical. I want to know what is the common ways of real web programmers usually do when they have to divide his webpage into different sections and set its height to window height , then make sure the other effects that's depends on the section height works properly and avoid to wait the height change for a second?

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• Pointers to a typed variable in C#: Interfase, Generic, object or Class? (Boxing/Unboxing)

  - by PaulG

  First of all, I apologize if this has been asked a thousand times. I read my C# book, I googled it, but I can't seem to find the answer I am looking for, or I am missing the point big time. I am very confused with the whole boxing/unboxing issue. Say I have fields of different classes, all returning typed variables (e.g. 'double') and I would like to have a variable point to any of these fields. In plain old C I would do something like: double * newVar; newVar = &oldVar; newVar = &anotherVar; ... In C#, it seems I could do an interfase, but would require that all fields be properties and named the same. Breaks apart when one of the properties doesn't have the same name or is not a property. I could also create a generic class returning double, but seems a bit absurd to create a class to represent a 'double', when a 'double' class already exists. If I am not mistaken, it doesn't even need to be generic, could be a simple class returning double. I could create an object and box the typed variable to the newly created object, but then I would have to cast every time I use it. Of course, I always have the unsafe option... but afraid of getting to unknown memory space, divide by zero and bring an end to this world. None of these seem to be the same as the old simple 'double * variable'. Am I missing something here?

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• Maximum length of a std::basic_string<_CharT> string

  - by themoondothshine

  Hey all, I was wondering how one can fix an upper limit for the length of a string (in C++) for a given platform. I scrutinized a lot of libraries, and most of them define it arbitrarily. The GNU C++ STL (the one with experimental C++0x features) has quite a definition: size_t npos = size_t(-1); /*!< The maximum value that can be stored in a variable of type size_t */ size_t _S_max_len = ((npos - sizeof(_Rep_base))/sizeof(_CharT) - 1) / 4; /*!< Where _CharT is a template parameter; _Rep_base is a structure which encapsulates the allocated memory */ Here's how I understand the formula: The size_t type must hold the count of units allocated to the string (where each unit is of type _CharT) Theoretically, the maximum value that a variable of type size_t can take on is the total number of units of 1 byte (ie, of type char) that may be allocated The previous value minus the overhead required to keep track of the allocated memory (_Rep_base) is therefore the maximum number of units in a string. Divide this value by sizeof(_CharT) as _CharT may require more than a byte Subtract 1 from the previous value to account for a terminating character Finally, that leave the division by 4. I have absolutely no idea why! I looked at a lot of places for an explanation, but couldn't find a satisfactory one anywhere (that's why I've been trying to make up something for it! Please correct me if I'm wrong!!).

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• EventHandlers saved to databases.

  - by Stacey

  In a database application (using Sql Server right now, in C#, with Entity Framework 4.0) I have a situation where I need to trigger events when some values change. For instance assume a class "Trackable". class Trackable { string Name { get; set; } int Positive { get; set; } int Negative { get; set; } int Total { get; set; } // event OnChanged } Trackable is represented in the database as follows; table Trackables Id | guid name | varchar(32) positive | int negative | int Total is of course, calculated at runtime. When a trackable event changes, I want to inspect its previous value, and then see what it is changing to, and be capable of reacting accordingly. However different trackables need to trigger different events (to avoid a huge, massive cascading switch/if block). If this were just only C# code it would be easy - but they have to be saved to the database. I can't divide up each different trackable into a different table/class, that would be silly - they are all identical, but the event raised is different based on how they are made. So I guess my question is, is there any way to store an event handler in a database such that.. Trackable t1 = new Trackable() { Name = "Trackable1" OnChange += TrackableChangedEventHandler(OnTrackable1Change) } Trackable t2 = new Trackable() { Name = "Trackable2", OnChange += TrackableChangedEventHandler(OnTrackable2Change) }

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• How can I measure my (SAMP) server's bandwidth usage?

  - by enkrates

  I'm running a Solaris server to serve PHP through Apache. What tools can I use to measure the bandwidth my server is currently using? I use Google analytics to measure traffic, but as far as I know, it ignores file size. I have a rough idea of the average size of the pages I serve, and can do a back-of-the-envelope calculation of my bandwidth usage by multiplying page views (from Google) by average page size, but I'm looking for a solution that is more rigorous and exact. Also, I'm not trying to throttle anything, or implement usage caps or anything like that. I'd just like to measure the bandwidth usage, so I know what it is. An example of what I'm after is the usage meter that Slicehost provides in their admin website for their users. They tell me (for another site I run) how much bandwidth I've used each month and also divide the usage for uploading and downloading. So, it seems like this data can be measured, and I'd like to be able to do it myself. To put it simply, what is the conventional method for measuring the bandwidth usage of my server?

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• Height:100% is not considered

  - by Ivan90

  Hi guys, I would want to simulate the behavior of a table with div. I have a struct of my layout divide into three columns: div#wrapper { width:800px; float:left; height:100%; margin-top:7px; text-align:center; } div#left { width:167px; float:left; padding-bottom:50px; margin-right:3px; } div#main { width:454px; float:left; } div#right { width:167px; float:left; margin-left:3px; } wrapper is the container of three columns left,main,right div "main" have a variable content so in some case is more long and in other case is very short. When the content vary,div wrapper is adapted and it's ok but left and right columns don't adapt to wrapper. P.S Without doctype there is no problem, infact I set the height of left, main and right to 100% but when I insert transional.dtd , the height of div is not considered. How can resolve this problem? Sorry for my english!!

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• How to prepare for a telephone interview: ‘Develop an Interview Cheat Sheet’

  - by Maria Sandu

  At Oracle we often do telephone interviews in different stages of the process with candidates, due to the fact that we hire native speakers into other countries. On this blog we already have an article with tips and tricks for phone interviews that can help you during the telephone interviews. To help you prepare even better for a telephone interview we would like to introduce you the basics of developing a cheat sheet. The benefit of a telephone interview is that you will be sitting at home, at your table or desk, during the interview, and not in front of someone. So use this to your advantage. The Monster website has some useful and interesting tips and tricks for developing a cheat sheet. Carole Martin, who wrote this article, says that a cheat sheet will help you feel more prepared and confident when speaking to managers over the phone. Important to keep in mind is that you shouldn't memorise what's on the sheet or check it off during the interview. Only use your cheat sheet to remind you of key facts. Here are some suggestions to include on it: • Divide a piece of paper in 2 by drawing a line. Write on one side of the paper a list of requirements as mentioned in the job description. On the other side list your qualities to fulfill the requirements of the employer. This will help you in answering questions about why you are the best candidate for the job and how you fit the role. • Do research on the company, the industry sector and the competitors, so you will get a feeling for the company’s business and can ask more in-depth questions. • Be prepared for the most used introduction question: “Tell me a bit about yourself”. Prepare a 60-second personal statement or pitch in which you summarise who you are and what you can offer, so you will be able to sell yourself from on the very beginning. • Write down a minimum of 5 good examples to answer behavioral interview questions ("Tell me about a time when..." or "Give me an example of a time..." ). These questions are used by interviewers to see how you deal with similar situations as you might encounter in the job. Interviewers use this question as past behaviour is scientifically proven to be the best predictor for future behaviour. • List five questions to ask the interviewer about the job, the company and the industry to help you get a good understanding if the role and company really fit your needs and wants. To get some inspiration check this article on inc.com • Find out how much you are worth on the job market and determine your needs based on your living expenses, especially when moving abroad. • Ask for permission from the people you plan to use as a reference. Also make sure you have your CV at hand and an overview of your grades. Feel free to comment on this article and let us know what your experience is with developing a cheat sheet for a telephone interview. Good luck with the preparation of your sheet.

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• Algorithm to Find the Aggregate Mass of "Granola Bar"-Like Structures?

  - by Stuart Robbins

  I'm a planetary science researcher and one project I'm working on is N-body simulations of Saturn's rings. The goal of this particular study is to watch as particles clump together under their own self-gravity and measure the aggregate mass of the clumps versus the mean velocity of all particles in the cell. We're trying to figure out if this can explain some observations made by the Cassini spacecraft during the Saturnian summer solstice when large structures were seen casting shadows on the nearly edge-on rings. Below is a screenshot of what any given timestep looks like. (Each particle is 2 m in diameter and the simulation cell itself is around 700 m across.) The code I'm using already spits out the mean velocity at every timestep. What I need to do is figure out a way to determine the mass of particles in the clumps and NOT the stray particles between them. I know every particle's position, mass, size, etc., but I don't know easily that, say, particles 30,000-40,000 along with 102,000-105,000 make up one strand that to the human eye is obvious. So, the algorithm I need to write would need to be a code with as few user-entered parameters as possible (for replicability and objectivity) that would go through all the particle positions, figure out what particles belong to clumps, and then calculate the mass. It would be great if it could do it for "each" clump/strand as opposed to everything over the cell, but I don't think I actually need it to separate them out. The only thing I was thinking of was doing some sort of N2 distance calculation where I'd calculate the distance between every particle and if, say, the closest 100 particles were within a certain distance, then that particle would be considered part of a cluster. But that seems pretty sloppy and I was hoping that you CS folks and programmers might know of a more elegant solution? Edited with My Solution: What I did was to take a sort of nearest-neighbor / cluster approach and do the quick-n-dirty N2 implementation first. So, take every particle, calculate distance to all other particles, and the threshold for in a cluster or not was whether there were N particles within d distance (two parameters that have to be set a priori, unfortunately, but as was said by some responses/comments, I wasn't going to get away with not having some of those). I then sped it up by not sorting distances but simply doing an order N search and increment a counter for the particles within d, and that sped stuff up by a factor of 6. Then I added a "stupid programmer's tree" (because I know next to nothing about tree codes). I divide up the simulation cell into a set number of grids (best results when grid size ˜7 d) where the main grid lines up with the cell, one grid is offset by half in x and y, and the other two are offset by 1/4 in ±x and ±y. The code then divides particles into the grids, then each particle N only has to have distances calculated to the other particles in that cell. Theoretically, if this were a real tree, I should get order N*log(N) as opposed to N2 speeds. I got somewhere between the two, where for a 50,000-particle sub-set I got a 17x increase in speed, and for a 150,000-particle cell, I got a 38x increase in speed. 12 seconds for the first, 53 seconds for the second, 460 seconds for a 500,000-particle cell. Those are comparable speeds to how long the code takes to run the simulation 1 timestep forward, so that's reasonable at this point. Oh -- and it's fully threaded, so it'll take as many processors as I can throw at it.

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• 256 Worker Role 3D Rendering Demo is now a Lab on my Azure Course

  - by Alan Smith

  Ever since I came up with the crazy idea of creating an Azure application that would spin up 256 worker roles (please vote if you like it ) to render a 3D animation created using the Kinect depth camera I have been trying to think of something useful to do with it. I have also been busy working on developing training materials for a Windows Azure course that I will be delivering through a training partner in Stockholm, and for customers wanting to learn Windows Azure. I hit on the idea of combining the render demo and a course lab and creating a lab where the students would create and deploy their own mini render farms, which would participate in a single render job, consisting of 2,000 frames. The architecture of the solution is shown below. As students would be creating and deploying their own applications, I thought it would be fun to introduce some competitiveness into the lab. In the 256 worker role demo I capture the rendering statistics for each role, so it was fairly simple to include the students name in these statistics. This allowed the process monitor application to capture the number of frames each student had rendered and display a high-score table. When I demoed the application I deployed one instance that started rendering a frame every few minutes, and the challenge for the students was to deploy and scale their applications, and then overtake my single role instance by the end of the lab time. I had the process monitor running on the projector during the lab so the class could see the progress of their deployments, and how they were performing against my implementation and their classmates. When I tested the lab for the first time in Oslo last week it was a great success, the students were keen to be the first to build and deploy their solution and then watch the frames appear. As the students mostly had MSDN suspicions they were able to scale to the full 20 worker role instances and before long we had over 100 worker roles working on the animation. There were, however, a few issues who the couple of issues caused by the competitive nature of the lab. The first student to scale the application to 20 instances would render the most frames and win; there was no way for others to catch up. Also, as they were competing against each other, there was no incentive to help others on the course get their application up and running. I have now re-written the lab to divide the student into teams that will compete to render the most frames. This means that if one developer on the team can deploy and scale quickly, the other team still has a chance to catch up. It also means that if a student finishes quickly and puts their team in the lead they will have an incentive to help the other developers on their team get up and running. As I was using “Sharks with Lasers” for a lot of my demos, and reserved the sharkswithfreakinlasers namespaces for some of the Azure services (well somebody had to do it), the students came up with some creative alternatives, like “Camels with Cannons” and “Honey Badgers with Homing Missiles”. That gave me the idea for the teams having to choose a creative name involving animals and weapons. The team rendering architecture diagram is shown below.   Render Challenge Rules In order to ensure fair play a number of rules are imposed on the lab. ·         The class will be divided into teams, each team choses a name. ·         The team name must consist of a ferocious animal combined with a hazardous weapon. ·         Teams can allocate as many worker roles as they can muster to the render job. ·         Frame processing statistics and rendered frames will be vigilantly monitored; any cheating, tampering, and other foul play will result in penalties. The screenshot below shows an example of the team render farm in action, Badgers with Bombs have taken a lead over Camels with Cannons, and both are  leaving the Sharks with Lasers standing. If you are interested in attending a scheduled delivery of my Windows Azure or Windows Azure Service bus courses, or would like on-site training, more details are here.

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• Persevering & Friday Night Big Ideas

  - by Oracle Accelerate for Midsize Companies

  by Jim Lein, Oracle Midsize Programs Every successful company, personal accomplishment, and philanthropic endeavor starts with one good idea. I have my best ideas on Friday evenings. The creative side of my brain is stimulated by end of week endorphins. Free thinking. Anything is possible. But, as my kids love to remind me, most of Dad's Friday Night Big Ideas (FNBIs) fizzle on the drawing board. Usually there's one barrier blocking the way that seems insurmountable by noon on Monday. For example, trekking the 486 mile Colorado Trail is on my bucket list. Since I have a job, I'll have to do it in bits and pieces--day hikes, weekends, and a vacation week here and there. With my trick neck, backpacking is not an option. How to survive equip myself for overnight backcountry travel was that one seemingly insurmountable barrier.  Persevering Lewis and Clark wouldn't have given up so I explored options and, as I blogged about back in December, I had an FNBI to hire llamas to carry my load. Last weekend, that idea came to fruition. Early Saturday morning, I met up with Bill, the owner of Antero Llamas, for an overnight training expedition along segment 14 of the Colorado Trail with a string of twelve llamas. It was a crash course on learning how to saddle, load, pasture, and mediate squabbles. Amazingly, we left the trailhead with me, the complete novice, at the lead. Instead of trying to impart three decades of knowledge on me in two days, Bill taught me two things: "Go With the Flow" and "Plan B". It worked. There were times I would be lost in thought for long stretches of time until one snort would remind me that I had a string of twelve llamas trailing behind. A funny thing happened along the trail... Up until last Saturday, my plan had been to trek all 28 segments of the trail east to west and sequentially. Out of some self-imposed sense of decorum. That plan presented myriad logistical challenges such as impassable snow pack on the Continental Divide when segment 6 is up next. On Sunday, as we trekked along the base of 14,000 ft peaks, I applied Bill's llama handling philosophy to my quest and came up with a much more realistic and enjoyable strategy for achieving my goal.  Seize opportunities to hike regardless of order. Define my own segments. Go west to east for awhile if it makes more sense. Let the llamas carry more creature comforts. Chill out.  I will still set foot on all 486 miles of the trail. Technically, the end result will be the same.And I and my traveling companions--human and camelid--will enjoy the journey more. Much more. Got Big Ideas of Your Own? Check out Tongal. This growing Oracle customer works with brands to crowd source fantastic ideas for promoting products and services. Your great idea could earn you cash.  Looking for more news and information about Oracle Solutions for Midsize Companies? Read the latest Oracle for Midsize Companies Newsletter Sign-up to receive the latest communications from Oracle’s industry leaders and experts Jim Lein I evangelize Oracle's enterprise solutions for growing midsize companies. I recently celebrated 15 years with Oracle, having joined JD Edwards in 1999. I'm based in Evergreen, Colorado and love relating stories about creativity and innovation whether they be about software, live music, or the mountains. The views expressed here are my own, and not necessarily those of Oracle.

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• Three Buckets of Knowledge

  - by BuckWoody

  As I learn more and more about SQL Server every day, I divide up my information into three “buckets”: Concepts In the first bucket are the general concepts about the topic. What is it? What does it do (or sometimes, what is is supposed to do?) How does one operation flow to another? For this information I use books, magazine articles and believe it or not – Wikipedia. I don’t always trust that last source, but I do use it to see how others lay out their thoughts around a concept. I really like graphical charts that show me the process flow if I can get it, and this is an ideal place for a good presentation. In fact, this may be the only real use for a presentation – I’ll explain what I mean in a moment. Reference The references for a topic include things like Transact-SQL (T-SQL) syntax, or the screen layout on a panel, things like that. Think Dictionary. The only reference I trust for this information is Books Online – presentations are fine, but we’re talking about a dictionary. Ever go to a movie that just reads through a dictionary? Me neither. But I have gone to presentations where people try to include tons of reference materials in their slides. Even if you give me the presentation material later, it’s not really a searchable, readable medium. How To A how-to for me is an example, or even better, a tutorial about an example. Whatever it is shows me a practical use for the concepts and of course involves the syntax. The important thing here is that you need to be able to separate out the example the person is showing you from the stuff you need to know. I can’t tell you how many times folks have told me, “well, sure, if yours is red then that works. But mine is blue.” And I have to explain, “then use “blue” for the search word here.” You get the idea. No one will do your work for you – the examples are meant as a teaching tool only. I accept that, learn what I can, and then run off to create my own thing. You might think a How To works well in a presentation, and it does, for the most part. For a complex example or tutorial, I still prefer the printed word (electronic if possible) so that I can go over the example multiple times, skip around and so on.   The order here isn’t actually that important. Most of the time I start with a concept, look at an example, and then read the reference material. But sometimes I look up an example, read a little of concepts and then check the reference. The only primary thing I try to enforce is to read something from each of them. It’s dangerous to base your work on any single example, reference or concept.  Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Consumer Oriented Search In Oracle Endeca Information Discovery - Part 2

  - by Bob Zurek

  As discussed in my last blog posting on this topic, Information Discovery, a core capability of the Oracle Endeca Information Discovery solution enables businesses to search, discover and navigate through a wide variety of big data including structured, unstructured and semi-structured data. With search as a core advanced capabilities of our product it is important to understand some of the key differences and capabilities in the underlying data store of Oracle Endeca Information Discovery and that is our Endeca Server. In the last post on this subject, we talked about Exploratory Search capabilities along with support for cascading relevance. Additional search capabilities in the Endeca Server, which differentiate from simple keyword based "search boxes" in other Information Discovery products also include: The Endeca Server Supports Set Search.  The Endeca Server is organized around set retrieval, which means that it looks at groups of results (all the documents that match a search), as well as the relationship of each individual result to the set. Other approaches only compute the relevance of a document by comparing the document to the search query – not by comparing the document to all the others. For example, a search for “U.S.” in another approach might match to the title of a document and get a high ranking. But what if it were a collection of government documents in which “U.S.” appeared in many titles, making that clue less meaningful? A set analysis would reveal this and be used to adjust relevance accordingly. The Endeca Server Supports Second-Order Relvance. Unlike simple search interfaces in traditional BI tools, which provide limited relevance ranking, such as a list of results based on key word matching, Endeca enables users to determine the most salient terms to divide up the result. Determining this second-order relevance is the key to providing effective guidance. Support for Queries and Filters. Search is the most common query type, but hardly complete, and users need to express a wide range of queries. Oracle Endeca Information Discovery also includes navigation, interactive visualizations, analytics, range filters, geospatial filters, and other query types that are more commonly associated with BI tools. Unlike other approaches, these queries operate across structured, semi-structured and unstructured content stored in the Endeca Server. Furthermore, this set is easily extensible because the core engine allows for pluggable features to be added. Like a search engine, queries are answered with a results list, ranked to put the most likely matches first. Unlike “black box” relevance solutions, which generalize one strategy for everyone, we believe that optimal relevance strategies vary across domains. Therefore, it provides line-of-business owners with a set of relevance modules that let them tune the best results based on their content. The Endeca Server query result sets are summarized, which gives users guidance on how to refine and explore further. Summaries include Guided Navigation® (a form of faceted search), maps, charts, graphs, tag clouds, concept clusters, and clarification dialogs. Users don’t explicitly ask for these summaries; Oracle Endeca Information Discovery analytic applications provide the right ones, based on configurable controls and rules. For example, the analytic application might guide a procurement agent filtering for in-stock parts by visualizing the results on a map and calculating their average fulfillment time. Furthermore, the user can interact with summaries and filters without resorting to writing complex SQL queries. The user can simply just click to add filters. Within Oracle Endeca Information Discovery, all parts of the summaries are clickable and searchable. We are living in a search driven society where business users really seem to enjoy entering information into a search box. We do this everyday as consumers and therefore, we have gotten used to looking for that box. However, the key to getting the right results is to guide that user in a way that provides additional Discovery, beyond what they may have anticipated. This is why these important and advanced features of search inside the Endeca Server have been so important. They have helped to guide our great customers to success. 

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• Exchange 2007 Standard Edition

  - by Phrontiste

  We Have : Exchange 2007 Standard Edition IBM System X3650 2 x Intel Xeon 5430 2.66 GHz Version 8.1 Build 240.6 Mailbox, Hub Transport, Client Access Role Installed on One Box Total Number of Mailboxes : 110 - 130 6 Physical Disks Disk 0,1 (68 GB) = Raid-1, OS Partition ( C: Partition) Disk 2,3 (279GB) = Raid-1, Exchange Database (First and Second Storage Groups) ( D: Partition ) Disk 4,5 (68 GB) = Raid-1, Exchange Transaction Logs ( E: Partition ) Setup: Storage Groups : D:\First Storage group\Mailbox database.edb Storage Groups : D:\Second Storage Group\Public Folder Database.edb Transaction Logs : E Partition Problem 1: On our D Partition (Mailbox Database Partition), total size is 279 GB, free space remaining is 64.7 GB, when I select the first storage group and second storage group folders and right click properties they report a size of 165 GB. Mailbox database reports a size of 157GB when right clicked Properties. where as the size displayed in the folder is 164,893,456 KB So, we are missing around 50-54 GB, there is nothing else on these drives, no page file, nothing at all. The partition housing the Transaction logs is reporting the sizes accurately. Any suggestions / fixes on the above ? Problem 2: As you may have already read in Problem 1, the size of the mailbox database is 157GB or 164GB reported; which is not recommended, a) What would you suggest we should do to divide mailboxes in storage groups on this same server ? b) How would we move mailboxes into different storage groups ? c) This is the information store size ? (Am I right in thinking that this is not recommended) d) Having multiple storage groups with one Mailbox DB in each, would that reduce the size of the Information Store? e) Any suggestions / how-to reduce the size of information store ? We didn't install this, we have inherited this - what other recommendations you can make in order to keep ourselves better prepared for any server disaster? We are backing up with Yosemite Backup on RD1000 (320GB) at the moment, which is backing up successfully, flushing the logs daily. We haven't done a test restore YET. I have tried to provide as much info as possible, please let me know if you need further info. Also, we haven't yet faced any problems in mailflow, access speeds, everything is working fine, we have two to five people accessing OWA or Outlook via vpn only. Thanks for your time to read the above - will look forward to your expert suggestions.

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• Start a software company offshore

  - by Mascarpone

  Hello Everybody, I own a small, very young, EU based (Italy) company, and among other things, we sell IT solutions. I have a degree in applied mathematics, and I mainly deal with user interfaces, embedded systems, automation and web applications. You can say that I'm an enlightened entrepreneur because I work only with open source software (OS, IDE, I release under BSD , ... everything is free as in freedom), I give high importance to post sales services and customer satisfaction, plus I think I'm the best boss someone could desire (LOL), as I have google in mind when I think about IT workers rights. But the most beautiful thing is that, although everybody advised us not to use open source, is that we are quite profitable!!! (for the sixth trimester in a row). Now I offshore most of the work to an Indian company. I divide the work in modules and I outsource the longer or more trivial ones. I spend a lot of time defining the specifications and I leave the hard work to them. Using productivity bonuses, a lot of prototypes and third-party audits I think that my software has reached a very good quality level. I would like to start my own software development company, in order to improve control over process and cut costs. Obviously I can't afford the cost of labor in the EU, so I thought about opening a company in Asia. What I need Is: 1) Cheap labor - I can afford to give productivity bonuses and higher than average wages and stay profitable just because labor is cheap. 2) Many talents - I need a good level of tertiary education, and a good number of graduates, so I can hire junior developers and train and teach them according to my needs and philosophies (e.g.: open source mind) 3) Good infrastructure - buildings, transport, internet, .... everything that a company might need. I thought about 3 possible candidates: 1) India - I already work with indian people, I know that they are realiable and speak a good english. Big cities are too expensive, but maybe a small city like lucknow http://en.wikipedia.org/wiki/Lucknow could suits my needs. 2) China - They say it's cheaper than India, but I everytime I worked with a chineese company the language was a big barrier. They work hard, are somewhat skilled and cheap but maybe it's a risky path. Plus I feel a little uncofortable with their lack of human rights. 3) Philippines - Same as china: cheaper than india, but maybe less educated. Where do you think it's the best place to start a software company? Any reading or book to advise? thank you very much

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• The How-To Geek Holiday Gift Guide (Geeky Stuff We Like)

  - by The Geek

  Welcome to the very first How-To Geek Holiday Gift Guide, where we’ve put together a list of our absolute favorites to help you weed through all of the junk out there to pick the perfect gift for anybody. Though really, it’s just a list of the geeky stuff we want. We’ve got a whole range of items on the list, from cheaper gifts that most anybody can afford, to the really expensive stuff that we’re pretty sure nobody is giving us. Stocking Stuffers Here’s a couple of ideas for items that won’t break the bank. LED Keychain Micro-Light   Magcraft 1/8-Inch Rare Earth Cube Magnets Best little LED keychain light around. If they don’t need the penknife of the above item this is the perfect gift. I give them out by the handfuls and nobody ever says anything but good things about them. I’ve got ones that are years old and still running on the same battery.  Price: $8   Geeks cannot resist magnets. Jason bought this pack for his fridge because he was sick of big clunky magnets… these things are amazing. One tiny magnet, smaller than an Altoid mint, can practically hold a clipboard right to the fridge. Amazing. I spend more time playing with them on the counter than I do actually hanging stuff.  Price: $10 Lots of Geeky Mugs   Astronomy Powerful Green Laser Pointer There’s loads of fun, geeky mugs you can find on Amazon or anywhere else—and they are great choices for the geek who loves their coffee. You can get the Caffeine mug pictured here, or go with an Atari one, Canon Lens, or the Aperture mug based on Portal. Your choice. Price: $7   No, it’s not a light saber, but it’s nearly bright enough to be one—you can illuminate low flying clouds at night or just blind some aliens on your day off. All that for an extremely low price. Loads of fun. Price: $15       Geeky TV Shows and Books Sometimes you just want to relax and enjoy a some TV or a good book. Here’s a few choices. The IT Crowd Fourth Season   Doctor Who, Complete Fifth Series Ridiculous, funny show about nerds in the IT department, loved by almost all the geeks here at HTG. Justin even makes this required watching for new hires in his office so they’ll get his jokes. You can pre-order the fourth season, or pick up seasons one, two, or three for even cheaper. Price: $13   It doesn’t get any more nerdy than Eric’s pick, the fifth all-new series of Doctor Who, where the Daleks are hatching a new master plan from the heart of war-torn London. There’s also alien vampires, humanoid reptiles, and a lot more. Price: $52 Battlestar Galactica Complete Series   MAKE: Electronics: Learning Through Discovery Watch the epic fight to save the human race by finding the fabled planet Earth while being hunted by the robotic Cylons. You can grab the entire series on DVD or Blu-ray, or get the seasons individually. This isn’t your average sci-fi TV show. Price: $150 for Blu-ray.   Want to learn the fundamentals of electronics in a fun, hands-on way? The Make:Electronics book helps you build the circuits and learn how it all works—as if you had any more time between all that registry hacking and loading software on your new PC. Price: $21       Geeky Gadgets for the Gadget-Loving Geek Here’s a few of the items on our gadget list, though lets be honest: geeks are going to love almost any gadget, especially shiny new ones. Klipsch Image S4i Premium Noise-Isolating Headset with 3-Button Apple Control   GP2X Caanoo MAME/Console Emulator If you’re a real music geek looking for some serious quality in the headset for your iPhone or iPod, this is the pair that Alex recommends. They aren’t terribly cheap, but you can get the less expensive S3 earphones instead if you prefer. Price: $50-100   Eric says: “As an owner of an older version, I can say the GP2X is one of my favorite gadgets ever. Touted a “Retro Emulation Juggernaut,” GP2X runs Linux and may be the only open source software console available. Sounds too good to be true, but isn’t.” Price: $150 Roku XDS Streaming Player 1080p   Western Digital WD TV Live Plus HD Media Player If you do a lot of streaming over Netflix, Hulu Plus, Amazon’s Video on Demand, Pandora, and others, the Roku box is a great choice to get your content on your TV without paying a lot of money.  It’s also got Wireless-N built in, and it supports full 1080P HD. Price: $99   If you’ve got a home media collection sitting on a hard drive or a network server, the Western Digital box is probably the cheapest way to get that content on your TV, and it even supports Netflix streaming too. It’ll play loads of formats in full HD quality. Price: $99 Fujitsu ScanSnap S300 Color Mobile Scanner   Doxie, the amazing scanner for documents Trevor said: “This wonderful little scanner has become absolutely essential to me. My desk used to just be a gigantic pile of papers that I didn’t need at the moment, but couldn’t throw away ‘just in case.’ Now, every few weeks, I’ll run that paper pile through this and then happily shred the originals!” Price: $300   If you don’t scan quite as often and are looking for a budget scanner you can throw into your bag, or toss into a drawer in your desk, the Doxie scanner is a great alternative that I’ve been using for a while. It’s half the price, and while it’s not as full-featured as the Fujitsu, it might be a better choice for the very casual user. Price: $150       (Expensive) Gadgets Almost Anybody Will Love If you’re not sure that one of the more geeky presents is gonna work, here’s some gadgets that just about anybody is going to love, especially if they don’t have one already. Of course, some of these are a bit on the expensive side—but it’s a wish list, right? Amazon Kindle       The Kindle weighs less than a paperback book, the screen is amazing and easy on the eyes, and get ready for the kicker: the battery lasts at least a month. We aren’t kidding, either—it really lasts that long. If you don’t feel like spending money for books, you can use it to read PDFs, and if you want to get really geeky, you can hack it for custom screensavers. Price: $139 iPod Touch or iPad       You can’t go wrong with either of these presents—the iPod Touch can do almost everything the iPhone can do, including games, apps, and music, and it has the same Retina display as the iPhone, HD video recording, and a front-facing camera so you can use FaceTime. Price: $229+, depending on model. The iPad is a great tablet for playing games, browsing the web, or just using on your coffee table for guests. It’s well worth buying one—but if you’re buying for yourself, keep in mind that the iPad 2 is probably coming out in 3 months. Price: $500+ MacBook Air  The MacBook Air comes in 11” or 13” versions, and it’s an amazing little machine. It’s lightweight, the battery lasts nearly forever, and it resumes from sleep almost instantly. Since it uses an SSD drive instead of a hard drive, you’re barely going to notice any speed problems for general use. So if you’ve got a lot of money to blow, this is a killer gift. Price: $999 and up. Stuck with No Idea for a Present? Gift Cards! Yeah, you’re not going to win any “thoughtful present” awards with these, but you might just give somebody what they really want—the new Angry Birds HD for their iPad, Cut the Rope, or anything else they want. ITunes Gift Card   Amazon.com Gift Card Somebody in your circle getting a new iPod, iPhone, or iPad? You can get them an iTunes gift card, which they can use to buy music, games or apps. Yep, this way you can gift them a copy of Angry Birds if they don’t already have it. Or even Cut the Rope.   No clue what to get somebody on your list? Amazon gift cards let them buy pretty much anything they want, from organic weirdberries to big screen TVs. Yeah, it’s not as thoughtful as getting them a nice present, but look at the bright side: maybe they’ll get you an Amazon gift card and it’ll balance out. That’s the highlights from our lists—got anything else to add? Share your geeky gift ideas in the comments. Latest Features How-To Geek ETC The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Our Favorite Tech: What We’re Thankful For at How-To Geek The How-To Geek Guide to Learning Photoshop, Part 7: Design and Typography Happy Snow Bears Theme for Chrome and Iron [Holiday] Download Full Command and Conquer: Tiberian Sun Game for Free Scorched Cometary Planet Wallpaper Quick Fix: Add the RSS Button Back to the Firefox Awesome Bar Dropbox Desktop Client 1.0.0 RC for Windows, Linux, and Mac Released Hang in There Scrat! – Ice Age Wallpaper

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• WebLogic Server Performance and Tuning: Part I - Tuning JVM

  - by Gokhan Gungor

  Each WebLogic Server instance runs in its own dedicated Java Virtual Machine (JVM) which is their runtime environment. Every Admin Server in any domain executes within a JVM. The same also applies for Managed Servers. WebLogic Server can be used for a wide variety of applications and services which uses the same runtime environment and resources. Oracle WebLogic ships with 2 different JVM, HotSpot and JRocket but you can choose which JVM you want to use. JVM is designed to optimize itself however it also provides some startup options to make small changes. There are default values for its memory and garbage collection. In real world, you will not want to stick with the default values provided by the JVM rather want to customize these values based on your applications which can produce large gains in performance by making small changes with the JVM parameters. We can tell the garbage collector how to delete garbage and we can also tell JVM how much space to allocate for each generation (of java Objects) or for heap. Remember during the garbage collection no other process is executed within the JVM or runtime, which is called STOP THE WORLD which can affect the overall throughput. Each JVM has its own memory segment called Heap Memory which is the storage for java Objects. These objects can be grouped based on their age like young generation (recently created objects) or old generation (surviving objects that have lived to some extent), etc. A java object is considered garbage when it can no longer be reached from anywhere in the running program. Each generation has its own memory segment within the heap. When this segment gets full, garbage collector deletes all the objects that are marked as garbage to create space. When the old generation space gets full, the JVM performs a major collection to remove the unused objects and reclaim their space. A major garbage collect takes a significant amount of time and can affect system performance. When we create a managed server either on the same machine or on remote machine it gets its initial startup parameters from $DOMAIN_HOME/bin/setDomainEnv.sh/cmd file. By default two parameters are set:     Xms: The initial heapsize     Xmx: The max heapsize Try to set equal initial and max heapsize. The startup time can be a little longer but for long running applications it will provide a better performance. When we set -Xms512m -Xmx1024m, the physical heap size will be 512m. This means that there are pages of memory (in the state of the 512m) that the JVM does not explicitly control. It will be controlled by OS which could be reserve for the other tasks. In this case, it is an advantage if the JVM claims the entire memory at once and try not to spend time to extend when more memory is needed. Also you can use -XX:MaxPermSize (Maximum size of the permanent generation) option for Sun JVM. You should adjust the size accordingly if your application dynamically load and unload a lot of classes in order to optimize the performance. You can set the JVM options/heap size from the following places:     Through the Admin console, in the Server start tab     In the startManagedWeblogic script for the managed servers     $DOMAIN_HOME/bin/startManagedWebLogic.sh/cmd     JAVA_OPTIONS="-Xms1024m -Xmx1024m" ${JAVA_OPTIONS}     In the setDomainEnv script for the managed servers and admin server (domain wide)     USER_MEM_ARGS="-Xms1024m -Xmx1024m" When there is free memory available in the heap but it is too fragmented and not contiguously located to store the object or when there is actually insufficient memory we can get java.lang.OutOfMemoryError. We should create Thread Dump and analyze if that is possible in case of such error. The second option we can use to produce higher throughput is to garbage collection. We can roughly divide GC algorithms into 2 categories: parallel and concurrent. Parallel GC stops the execution of all the application and performs the full GC, this generally provides better throughput but also high latency using all the CPU resources during GC. Concurrent GC on the other hand, produces low latency but also low throughput since it performs GC while application executes. The JRockit JVM provides some useful command-line parameters that to control of its GC scheme like -XgcPrio command-line parameter which takes the following options; XgcPrio:pausetime (To minimize latency, parallel GC) XgcPrio:throughput (To minimize throughput, concurrent GC ) XgcPrio:deterministic (To guarantee maximum pause time, for real time systems) Sun JVM has similar parameters (like  -XX:UseParallelGC or -XX:+UseConcMarkSweepGC) to control its GC scheme. We can add -verbosegc -XX:+PrintGCDetails to monitor indications of a problem with garbage collection. Try configuring JVM’s of all managed servers to execute in -server mode to ensure that it is optimized for a server-side production environment.

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• The JRockit Performance Counters

  - by Marcus Hirt

  Every now and then I get a question regarding what the attributes in the PerfCounters dynamic MBean represent. Now, all the MBeans under the oracle.jrockit.management (bea.jrockit.management pre R28) domain are part of what we call JMXMAPI (the JRockit JMX based Management API), which is unsupported. Therefore there is no official documentation for the API. I did however write a bit about JMXMAPI in my recent JRockit book, Oracle JRockit: The Definitive Guide. The information in the table below is from that book: Counter Description java.cls.loadedClasses The number of classes loaded since the start of the JVM. java.cls.unloadedClasses The number of classes unloaded since the start of the JVM. java.property.java.class.path The class path of the JVM. java.property.java.endorsed.dirs The endorsed dirs. See the Endorsed Standards Override Mechanism. java.property.java.ext.dirs The ext dirs, which are searched for jars that should be automatically put on the classpath. See the Java documentation for java.ext.dirs. java.property.java.home The root of the JDK or JRE installation. java.property.java.library.path The library path used to find user libraries. java.property.java.vm.version The JRockit version. java.rt.vmArgs The list of VM arguments. java.threads.daemon The number of running daemon threads. java.threads.live The total number of running threads. java.threads.livePeak The peak number of threads that has been running since JRockit was started. java.threads.nonDaemon The number of non-daemon threads running. java.threads.started The total number of threads started since the start of JRockit. jrockit.gc.latest.heapSize The current heap size in bytes. jrockit.gc.latest.nurserySize The current nursery size in bytes. jrockit.gc.latest.oc.compaction.time How long, in ticks, the last compaction lasted. Reset to 0 if compaction is skipped. jrockit.gc.latest.oc.heapUsedAfter Used heap at the end of the last OC, in bytes. jrockit.gc.latest.oc.heapUsedBefore Used heap at the start of the last OC, in bytes. jrockit.gc.latest.oc.number The number of OCs that have occurred so far. jrockit.gc.latest.oc.sumOfPauses The paused time for the last OC, in ticks. jrockit.gc.latest.oc.time The time the last OC took, in ticks. jrockit.gc.latest.yc.sumOfPauses The paused time for the last YC, in ticks. jrockit.gc.latest.yc.time The time the last YC took, in ticks. jrockit.gc.max.oc.individualPause The longest OC pause so far, in ticks. jrockit.gc.max.yc.individualPause The longest YC pause so far, in ticks. jrockit.gc.total.oc.compaction.externalAborted Number of aborted external compactions so far. jrockit.gc.total.oc.compaction.internalAborted Number of aborted internal compactions so far. jrockit.gc.total.oc.compaction.internalSkipped Number of skipped internal compactions so far. jrockit.gc.total.oc.compaction.time The total time spent doing compaction so far, in ticks. jrockit.gc.total.oc.ompaction.externalSkipped Number of skipped external compactions so far. jrockit.gc.total.oc.pauseTime The sum of all OC pause times so far, in ticks. jrockit.gc.total.oc.time The total time spent doing OC so far, in ticks. jrockit.gc.total.pageFaults The number of page faults that have occurred during GC so far. jrockit.gc.total.yc.pauseTime The sum of all YC pause times, in ticks. jrockit.gc.total.yc.promotedObjects The number of objects that all YCs have promoted. jrockit.gc.total.yc.promotedSize The total number of bytes that all YCs have promoted, in bytes. jrockit.gc.total.yc.time The total time spent doing YC, in ticks. oracle.ci.jit.count The number of methods JIT compiled. oracle.ci.jit.timeTotal The total time spent JIT compiling, in ticks. oracle.ci.opt.count The number of methods optimized. oracle.ci.opt.timeTotal The total time spent optimizing, in ticks. oracle.rt.counterFrequency Used to convert ticks values to seconds. Note that many of these counters are excellent choices for attributes to plot in the Management Console. Also note that many values are in ticks – to convert them to seconds, divide by the value in the oracle.rt.counterFrequency counter.

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• IBM "per core" comparisons for SPECjEnterprise2010

  - by jhenning

  I recently stumbled upon a blog entry from Roman Kharkovski (an IBM employee) comparing some SPECjEnterprise2010 results for IBM vs. Oracle. Mr. Kharkovski's blog claims that SPARC delivers half the transactions per core vs. POWER7. Prior to any argument, I should say that my predisposition is to like Mr. Kharkovski, because he says that his blog is intended to be factual; that the intent is to try to avoid marketing hype and FUD tactic; and mostly because he features a picture of himself wearing a bike helmet (me too). Therefore, in a spirit of technical argument, rather than FUD fight, there are a few areas in his comparison that should be discussed. Scaling is not free For any benchmark, if a small system scores 13k using quantity R1 of some resource, and a big system scores 57k using quantity R2 of that resource, then, sure, it's tempting to divide: is  13k/R1 > 57k/R2 ? It is tempting, but not necessarily educational. The problem is that scaling is not free. Building big systems is harder than building small systems. Scoring  13k/R1  on a little system provides no guarantee whatsoever that one can sustain that ratio when attempting to handle more than 4 times as many users. Choosing the denominator radically changes the picture When ratios are used, one can vastly manipulate appearances by the choice of denominator. In this case, lots of choices are available for the resource to be compared (R1 and R2 above). IBM chooses to put cores in the denominator. Mr. Kharkovski provides some reasons for that choice in his blog entry. And yet, it should be noted that the very concept of a core is: arbitrary: not necessarily comparable across vendors; fluid: modern chips shift chip resources in response to load; and invisible: unless you have a microscope, you can't see it. By contrast, one can actually see processor chips with the naked eye, and they are a bit easier to count. If we put chips in the denominator instead of cores, we get: 13161.07 EjOPS / 4 chips = 3290 EjOPS per chip for IBM vs 57422.17 EjOPS / 16 chips = 3588 EjOPS per chip for Oracle The choice of denominator makes all the difference in the appearance. Speaking for myself, dividing by chips just seems to make more sense, because: I can see chips and count them; and I can accurately compare the number of chips in my system to the count in some other vendor's system; and Tthe probability of being able to continue to accurately count them over the next 10 years of microprocessor development seems higher than the probability of being able to accurately and comparably count "cores". SPEC Fair use requirements Speaking as an individual, not speaking for SPEC and not speaking for my employer, I wonder whether Mr. Kharkovski's blog article, taken as a whole, meets the requirements of the SPEC Fair Use rule www.spec.org/fairuse.html section I.D.2. For example, Mr. Kharkovski's footnote (1) begins Results from http://www.spec.org as of 04/04/2013 Oracle SUN SPARC T5-8 449 EjOPS/core SPECjEnterprise2010 (Oracle's WLS best SPECjEnterprise2010 EjOPS/core result on SPARC). IBM Power730 823 EjOPS/core (World Record SPECjEnterprise2010 EJOPS/core result) The questionable tactic, from a Fair Use point of view, is that there is no such metric at the designated location. At www.spec.org, You can find the SPEC metric 57422.17 SPECjEnterprise2010 EjOPS for Oracle and You can also find the SPEC metric 13161.07 SPECjEnterprise2010 EjOPS for IBM. Despite the implication of the footnote, you will not find any mention of 449 nor anything that says 823. SPEC says that you can, under its fair use rule, derive your own values; but it emphasizes: "The context must not give the appearance that SPEC has created or endorsed the derived value." Substantiation and transparency Although SPEC disclaims responsibility for non-SPEC information (section I.E), it says that non-SPEC data and methods should be accurate, should be explained, should be substantiated. Unfortunately, it is difficult or impossible for the reader to independently verify the pricing: Were like units compared to like (e.g. list price to list price)? Were all components (hw, sw, support) included? Were all fees included? Note that when tpc.org shows IBM pricing, there are often items such as "PROCESSOR ACTIVATION" and "MEMORY ACTIVATION". Without the transparency of a detailed breakdown, the pricing claims are questionable. T5 claim for "Fastest Processor" Mr. Kharkovski several times questions Oracle's claim for fastest processor, writing You see, when you publish industry benchmarks, people may actually compare your results to other vendor's results. Well, as we performance people always say, "it depends". If you believe in performance-per-core as the primary way of looking at the world, then yes, the POWER7+ is impressive, spending its chip resources to support up to 32 threads (8 cores x 4 threads). Or, it just might be useful to consider performance-per-chip. Each SPARC T5 chip allows 128 hardware threads to be simultaneously executing (16 cores x 8 threads). The Industry Standard Benchmark that focuses specifically on processor chip performance is SPEC CPU2006. For this very well known and popular benchmark, SPARC T5: provides better performance than both POWER7 and POWER7+, for 1 chip vs. 1 chip, for 8 chip vs. 8 chip, for integer (SPECint_rate2006) and floating point (SPECfp_rate2006), for Peak tuning and for Base tuning. For example, at the 8-chip level, integer throughput (SPECint_rate2006) is: 3750 for SPARC 2170 for POWER7+. You can find the details at the March 2013 BestPerf CPU2006 page SPEC is a trademark of the Standard Performance Evaluation Corporation, www.spec.org. The two specific results quoted for SPECjEnterprise2010 are posted at the URLs linked from the discussion. Results for SPEC CPU2006 were verified at spec.org 1 July 2013, and can be rechecked here.

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• First time shadow mapping problems

  - by user1294203

  I have implemented basic shadow mapping for the first time in OpenGL using shaders and I'm facing some problems. Below you can see an example of my rendered scene: The process of the shadow mapping I'm following is that I render the scene to the framebuffer using a View Matrix from the light point of view and the projection and model matrices used for normal rendering. In the second pass, I send the above MVP matrix from the light point of view to the vertex shader which transforms the position to light space. The fragment shader does the perspective divide and changes the position to texture coordinates. Here is my vertex shader, #version 150 core uniform mat4 ModelViewMatrix; uniform mat3 NormalMatrix; uniform mat4 MVPMatrix; uniform mat4 lightMVP; uniform float scale; in vec3 in_Position; in vec3 in_Normal; in vec2 in_TexCoord; smooth out vec3 pass_Normal; smooth out vec3 pass_Position; smooth out vec2 TexCoord; smooth out vec4 lightspace_Position; void main(void){ pass_Normal = NormalMatrix * in_Normal; pass_Position = (ModelViewMatrix * vec4(scale * in_Position, 1.0)).xyz; lightspace_Position = lightMVP * vec4(scale * in_Position, 1.0); TexCoord = in_TexCoord; gl_Position = MVPMatrix * vec4(scale * in_Position, 1.0); } And my fragment shader, #version 150 core struct Light{ vec3 direction; }; uniform Light light; uniform sampler2D inSampler; uniform sampler2D inShadowMap; smooth in vec3 pass_Normal; smooth in vec3 pass_Position; smooth in vec2 TexCoord; smooth in vec4 lightspace_Position; out vec4 out_Color; float CalcShadowFactor(vec4 lightspace_Position){ vec3 ProjectionCoords = lightspace_Position.xyz / lightspace_Position.w; vec2 UVCoords; UVCoords.x = 0.5 * ProjectionCoords.x + 0.5; UVCoords.y = 0.5 * ProjectionCoords.y + 0.5; float Depth = texture(inShadowMap, UVCoords).x; if(Depth < (ProjectionCoords.z + 0.001)) return 0.5; else return 1.0; } void main(void){ vec3 Normal = normalize(pass_Normal); vec3 light_Direction = -normalize(light.direction); vec3 camera_Direction = normalize(-pass_Position); vec3 half_vector = normalize(camera_Direction + light_Direction); float diffuse = max(0.2, dot(Normal, light_Direction)); vec3 temp_Color = diffuse * vec3(1.0); float specular = max( 0.0, dot( Normal, half_vector) ); float shadowFactor = CalcShadowFactor(lightspace_Position); if(diffuse != 0 && shadowFactor > 0.5){ float fspecular = pow(specular, 128.0); temp_Color += fspecular; } out_Color = vec4(shadowFactor * texture(inSampler, TexCoord).xyz * temp_Color, 1.0); } One of the problems is self shadowing as you can see in the picture, the crate has its own shadow cast on itself. What I have tried is enabling polygon offset (i.e. glEnable(POLYGON_OFFSET_FILL), glPolygonOffset(GLfloat, GLfloat) ) but it didn't change much. As you see in the fragment shader, I have put a static offset value of 0.001 but I have to change the value depending on the distance of the light to get more desirable effects , which not very handy. I also tried using front face culling when I render to the framebuffer, that didn't change much too. The other problem is that pixels outside the Light's view frustum get shaded. The only object that is supposed to be able to cast shadows is the crate. I guess I should pick more appropriate projection and view matrices, but I'm not sure how to do that. What are some common practices, should I pick an orthographic projection? From googling around a bit, I understand that these issues are not that trivial. Does anyone have any easy to implement solutions to these problems. Could you give me some additional tips? Please ask me if you need more information on my code. Here is a comparison with and without shadow mapping of a close-up of the crate. The self-shadowing is more visible.

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• 2D OBB collision detection, resolving collisions?

  - by Milo

  I currently use OBBs and I have a vehicle that is a rigid body and some buildings. Here is my update() private void update() { camera.setPosition((vehicle.getPosition().x * camera.getScale()) - ((getWidth() ) / 2.0f), (vehicle.getPosition().y * camera.getScale()) - ((getHeight() ) / 2.0f)); //camera.move(input.getAnalogStick().getStickValueX() * 15.0f, input.getAnalogStick().getStickValueY() * 15.0f); if(input.isPressed(ControlButton.BUTTON_GAS)) { vehicle.setThrottle(1.0f, false); } if(input.isPressed(ControlButton.BUTTON_BRAKE)) { vehicle.setBrakes(1.0f); } vehicle.setSteering(input.getAnalogStick().getStickValueX()); vehicle.update(16.6666f / 1000.0f); ArrayList<Building> buildings = city.getBuildings(); for(Building b : buildings) { if(vehicle.getRect().overlaps(b.getRect())) { vehicle.update(-17.0f / 1000.0f); break; } } } The collision detection works well. What doesn't is how they are dealt with. My goal is simple. If the vehicle hits a building, it should stop, and never go into the building. When I apply negative torque to reverse the car should not feel buggy and move away from the building. I don't want this to look buggy. This is my rigid body class: class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position, getWidth(), getHeight(), angle); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { //integrate physics //linear Vector2D acceleration = Vector2D.scalarDivide(forces, mass); velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); c = Vector2D.add(getRect().getCenter(), Vector2D.scalarMultiply(velocity , timeStep)); setCenter(c.x, c.y); forces = new Vector2D(0,0); //clear forces //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { Matrix mat = new Matrix(); float[] Vector2Ds = new float[2]; Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); return new Vector2D(Vector2Ds[0], Vector2Ds[1]); } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { Matrix mat = new Matrix(); float[] Vectors = new float[2]; Vectors[0] = world.x; Vectors[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vectors); return new Vector2D(Vectors[0], Vectors[1]); } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { Vector2D tangent = new Vector2D(-worldOffset.y, worldOffset.x); return Vector2D.add( Vector2D.scalarMultiply(tangent, angularVelocity) , velocity); } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces = Vector2D.add(forces ,worldForce); //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } } Essentially, when any rigid body hits a building it should exhibit the same behavior. How is collision solving usually done? Thanks

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