Search Results

Search found 379 results on 16 pages for 'euler angles'.

Page 14/16 | < Previous Page | 10 11 12 13 14 15 16  | Next Page >

  • Getting Recognition for Open-Source Computer Language Projects

    - by Jon Purdy
    I like language a lot, so I write a lot of language-based solutions for programming, automation, and data definition. I'm very much a believer in open-source software, so lately I've started to push these projects to Sourceforge when I start them. I feel that these tools could be quite valuable in the right hands, and that they fill niches that otherwise go unfilled. The trouble, for me, is gaining recognition. No matter how useful the software I write, after a certain point I can no longer come up with anything to add or improve. Basically no one but me uses it, so it's not being attacked from enough angles to discover any new weaknesses. I cannot work on a project that doesn't have anything to do, but I won't have anything to do unless I gain recognition by working on it! This is greatly discouraging. It's like giving what you think is a really thoughtful gift to someone who just isn't paying attention. So I'm looking for advice on how to network and disseminate information about my projects so that they don't fizzle out like this. Are there any sites, newsgroups, or mailing lists that I've been completely missing?

    Read the article

  • ruby comma operator and step question

    - by ryan_m
    so, i'm trying to learn ruby by doing some project euler questions, and i've run into a couple things i can't explain, and the comma ?operator? is in the middle of both. i haven't been able to find good documentation for this, maybe i'm just not using the google as I should, but good ruby documentation seems a little sparse . . . 1: how do you describe how this is working? the first snippet is the ruby code i don't understand, the second is the code i wrote that does the same thing only after painstakingly tracing the first: #what is this doing? cur, nxt = nxt, cur + nxt #this, apparently, but how to describe the above? nxt = cur + nxt cur = nxt - cur 2: in the following example, how do you describe what the line with 'step' is doing? from what i can gather, the step command works like (range).step(step_size), but this seems to be doing (starting_point).step(ending_point, step_size). Am i right with this assumption? where do i find good doc of this? #/usr/share/doc/ruby1.9.1-examples/examples/sieve.rb # sieve of Eratosthenes max = Integer(ARGV.shift || 100) sieve = [] for i in 2 .. max sieve[i] = i end for i in 2 .. Math.sqrt(max) next unless sieve[i] (i*i).step(max, i) do |j| sieve[j] = nil end end puts sieve.compact.join(", ")

    Read the article

  • emacs: Inferior-mode python-shell appears "lagged"

    - by Begbie00
    Hi all - I'm a Python(3.1.2)/emacs(23.2) newbie teaching myself tkinter using the pythonware tutorial found here. Relevant code is pasted below the question. Question: when I click the Hello button (which should call the say_hi function) why does the inferior python shell (i.e. the one I kicked off with C-c C-c) wait to execute the say_hi print function until I either a) click the Quit button or b) close the root widget down? When I try the same in IDLE, each click of the Hello button produces an immediate print in the IDLE python shell, even before I click Quit or close the root widget. Is there some quirk in the way emacs runs the Python shell (vs. IDLE) that causes this "lagged" behavior? I've noticed similar emacs lags vs. IDLE as I've worked through Project Euler problems, but this is the clearest example I've seen yet. FYI: I use python.el and have a relatively clean init.el... (setq python-python-command "d:/bin/python31/python") is the only line in my init.el. Thanks, Mike === Begin Code=== from tkinter import * class App: def __init__(self,master): frame = Frame(master) frame.pack() self.button = Button(frame, text="QUIT", fg="red", command=frame.quit) self.button.pack(side=LEFT) self.hi_there = Button(frame, text="Hello", command=self.say_hi) self.hi_there.pack(side=LEFT) def say_hi(self): print("hi there, everyone!") root = Tk() app = App(root) root.mainloop()

    Read the article

  • F# Seq.initInfinite giving StackOverflowException

    - by TrueWill
    I'm learning F#, and I am having trouble understanding why this crashes. It's an attempt to solve Project Euler problem 2. let rec fibonacci n = if n = 1 then 1 elif n = 2 then 2 else fibonacci (n - 1) + fibonacci (n - 2) let debugfibonacci n = printfn "CALC: %d" n fibonacci n let isEven n = n % 2 = 0 let isUnderLimit n = n < 55 let getSequence = //[1..30] Seq.initInfinite (fun n -> n) |> Seq.map debugfibonacci |> Seq.filter isEven |> Seq.takeWhile isUnderLimit Seq.iter (fun x -> printfn "%d" x) getSequence The final version would call a sum function (and would have a higher limit than 55), but this is learning code. As is, this gives a StackOverflowException. However, if I comment in the [1..30] and comment out the Seq.initInfinite, I get: CALC: 1 CALC: 2 2 CALC: 3 CALC: 4 CALC: 5 8 CALC: 6 CALC: 7 CALC: 8 34 CALC: 9 CALC: 10 CALC: 11 It appears to be generating items on demand, as I would expect in LINQ. So why does it blow up when used with initInfinite?

    Read the article

  • Changing variables outside of Scope C#

    - by sam
    Hi, I'm a beginner C# programmer, and to improve my skills I decided to give Project Euler a try. The first problem on the site asks you to find the sum of all the multiples of 3 and 5 under 1000. Since I'm essentially doing the same thing twice, I made a method to multiply a base number incrementally, and add the sum of all the answers togethor. public static int SumOfMultiplication(int Base, int limit) { bool Escape = false; for (int mult = 1; Escape == true; mult++) { int Number = 0; int iSum = 0; Number = Base * mult; if (Number > limit) return iSum; else iSum = iSum + Number; } regardless of what I put in for both parameters, it ALWAYS returns zero. I'm 99% sure it has something to do with the scope of the variables, but I have no clue how to fix it. All help is appreciated. Thanks in advance, Sam

    Read the article

  • Are functional programming languages good for practical tasks?

    - by Clueless
    It seems to me from my experimenting with Haskell, Erlang and Scheme that functional programming languages are a fantastic way to answer scientific questions. For example, taking a small set of data and performing some extensive analysis on it to return a significant answer. It's great for working through some tough Project Euler questions or trying out the Google Code Jam in an original way. At the same time it seems that by their very nature, they are more suited to finding analytical solutions than actually performing practical tasks. I noticed this most strongly in Haskell, where everything is evaluated lazily and your whole program boils down to one giant analytical solution for some given data that you either hard-code into the program or tack on messily through Haskell's limited IO capabilities. Basically, the tasks I would call 'practical' such as Aceept a request, find and process requested data, and return it formatted as needed seem to translate much more directly into procedural languages. The most luck I have had finding a functional language that works like this is Factor, which I would liken to a reverse-polish-notation version of Python. So I am just curious whether I have missed something in these languages or I am just way off the ball in how I ask this question. Does anyone have examples of functional languages that are great at performing practical tasks or practical tasks that are best performed by functional languages?

    Read the article

  • Would anybody recommend learning J/K/APL?

    - by ozan
    I came across J/K/APL a few months ago while working my way through some project euler problems, and was intrigued, to say the least. For every elegant-looking 20 line python solution I produced, there'd be a gobsmacking 20 character J solution that ran in a tenth of the time. I've been keen to learn some basic J, and have made a few attempts at picking up the vocabulary, but have found the learning curve to be quite steep. To those who are familiar with these languages, would you recommend investing some time to learn one (I'm thinking J in particular)? I would do so more for the purpose of satisfying my curiosity than for career advancement or some such thing. Some personal circumstances to consider, if you care to: I love mathematics, and use it daily in my work (as a mathematician for a startup) but to be honest I don't really feel limited by the tools that I use (like python + NumPy) so I can't use that excuse. I have no particular desire to work in the finance industry, which seems to be the main port of call for K users at least. Plus I should really learn C# as a next language as it's the primary language where I work. So practically speaking, J almost definitely shouldn't be the next language I learn. I'm reasonably familiar with MATLAB so using an array-based programming language wouldn't constitute a tremendous paradigm shift. Any advice from those familiar with these languages would be much appreciated.

    Read the article

  • Simple encryption - Sum of Hashes in C

    - by Dogbert
    I am attempting to demonstrate a simple proof of concept with respect to a vulnerability in a piece of code in a game written in C. Let's say that we want to validate a character login. The login is handled by the user choosing n items, (let's just assume n=5 for now) from a graphical menu. The items are all medieval themed: eg: _______________________________ | | | | | Bow | Sword | Staff | |-----------|-----------|-------| | Shield | Potion | Gold | |___________|___________|_______| The user must click on each item, then choose a number for each item. The validation algorithm then does the following: Determines which items were selected Drops each string to lowercase (ie: Bow becomes bow, etc) Calculates a simple string hash for each string (ie: `bow = b=2, o=15, w=23, sum = (2+15+23=40) Multiplies the hash by the value the user selected for the corresponding item; This new value is called the key Sums together the keys for each of the selected items; this is the final validation hash IMPORTANT: The validator will accept this hash, along with non-zero multiples of it (ie: if the final hash equals 1111, then 2222, 3333, 8888, etc are also valid). So, for example, let's say I select: Bow (1) Sword (2) Staff (10) Shield (1) Potion (6) The algorithm drops each of these strings to lowercase, calculates their string hashes, multiplies that hash by the number selected for each string, then sums these keys together. eg: Final_Validation_Hash = 1*HASH(Bow) + 2*HASH(Sword) + 10*HASH(Staff) + 1*HASH(Shield) + 6*HASH(Potion) By application of Euler's Method, I plan to demonstrate that these hashes are not unique, and want to devise a simple application to prove it. in my case, for 5 items, I would essentially be trying to calculate: (B)(y) = (A_1)(x_1) + (A_2)(x_2) + (A_3)(x_3) + (A_4)(x_4) + (A_5)(x_5) Where: B is arbitrary A_j are the selected coefficients/values for each string/category x_j are the hash values for each string/category y is the final validation hash (eg: 1111 above) B,y,A_j,x_j are all discrete-valued, positive, and non-zero (ie: natural numbers) Can someone either assist me in solving this problem or point me to a similar example (ie: code, worked out equations, etc)? I just need to solve the final step (ie: (B)(Y) = ...). Thank you all in advance.

    Read the article

  • Plotting an Arc in Discrete Steps

    - by phobos51594
    Good afternoon, Background My question relates to the plotting of an arbitrary arc in space using discrete steps. It is unique, however, in that I am not drawing to a canvas in the typical sense. The firmware I am designing is for a gcode interpreter for a CNC mill that will translate commands into stepper motor movements. Now, I have already found a similar question on this very site, but the methodology suggested (Bresenham's Algorithm) appears to be incompatable for moving an object in space, as it only relies on the calculation of one octant of a circle which is then mirrored about the remaining axes of symmetry. Furthermore, the prescribed method of calculation an arc between two arbitrary angles relies on trigonometry (I am implementing on a microcontroller and would like to avoid costly trig functions, if possible) and simply not taking the steps that are out of the range. Finally, the algorithm only is designed to work in one rotational direction (e.g. counterclockwise). Question So, on to the actual question: Does anyone know of a general-purpose algorithm that can be used to "draw" an arbitrary arc in discrete steps while still giving respect to angular direction (CW / CCW)? The final implementation will be done in C, but the language for the purpose of the question is irrelevant. Thank you in advance. References S.O post on drawing a simple circle using Bresenham's Algorithm: "Drawing" an arc in discrete x-y steps Wiki page describing Bresenham's Algorithm for a circle http://en.wikipedia.org/wiki/Midpoint_circle_algorithm Gcode instructions to be implemented (see. G2 and G3) http://linuxcnc.org/docs/html/gcode.html

    Read the article

  • Programming exercises in Java inheritance for intern

    - by Tenner
    I work for a small software development team, working primarily in Java, for a very large company. Our new intern showed up sight-unseen (not uncommon in my company). He has some C++ experience but no Java. Worse, he's never worked with inheritance in C++. Our code has a great deal of abstraction and a heavy reliance on inheritance. We need to get him up to speed as quickly as possible. Of course the rest of the team is busy, and so we can't take the time out of our day to teach a one-student 200-level CS course. Instead, I'd like to give him an actual programming project to work on which highlights how classes, interfaces, method overrides, etc. work. I've had him look at Project Euler, but most of the solutions end up being procedural, and not object-oriented programs. Do any of you have any somewhat-straightforward (and relatively quick) projects which you would give to an intern in this situation? Or, any recent (or current) students have a school project they'd be willing to share? Anyone else had this experience?

    Read the article

  • Optimally place a pie slice in a rectangle.

    - by Lisa
    Given a rectangle (w, h) and a pie slice with start angle and end angle, how can I place the slice optimally in the rectangle so that it fills the room best (from an optical point of view, not mathematically speaking)? I'm currently placing the pie slice's center in the center of the rectangle and use the half of the smaller of both rectangle sides as the radius. This leaves plenty of room for certain configurations. Examples to make clear what I'm after, based on the precondition that the slice is drawn like a unit circle: A start angle of 0 and an end angle of PI would lead to a filled lower half of the rectangle and an empty upper half. A good solution here would be to move the center up by 1/4*h. A start angle of 0 and an end angle of PI/2 would lead to a filled bottom right quarter of the rectangle. A good solution here would be to move the center point to the top left of the rectangle and to set the radius to the smaller of both rectangle sides. This is fairly easy for the cases I've sketched but it becomes complicated when the start and end angles are arbitrary. I am searching for an algorithm which determines center of the slice and radius in a way that fills the rectangle best. Pseudo code would be great since I'm not a big mathematician.

    Read the article

  • Linking Apache to Tomcat with multiple domains.

    - by Royce Thigpen
    Okay, so I've been working for a while on this, and have been searching, but so far I have not found any answers that actually answer what I want to know. I'm a little bit at the end of my rope with this one, but I'm hoping I can figure this out sometime soon. So I have Apache 2 installed and serving up standard webpages, but I also have that linked to a Tomcat instance for one of my domains currently supported. However, I want to add another domain to the server via Apache that points to a separate code base from the one I already have. I have been coming at this from several different angles, and I have determined that I just don't know enough about setting up these servers to really do what I want to do. Little information on my server: Currently running a single Tomcat5.5 instance with Apache 2, using mod_jk to connect them together. I have a worker in workers.properties that points it's "host" field to "localhost" with the correct port my Tomcat instance, so that all works. In my Tomcat server.xml file, I have a host defined as "localhost" that points at my webapp that I am currently serving up, with that host set as the defaultHost as well. One thought I had was that I could add a new worker with a different host than "localhost" (i.e. host2) and then define a new host in my server.xml file called "host2" to match it, but after reading around some on the internet, It seems the "host" of the worker must point to a server, and not a hostname in the Tomcat instance, is this correct? Again, a simple rundown of what I want: Setup in apache/tomcat combo such that www.domain1.com points at "webapp1" and www.domain2.com points at "webapp2".

    Read the article

  • Vector deltas and moving in unknown areas

    - by dekz
    Hi All, I was in need of a little math help that I can't seem to find the answer to, any links to documentation would be greatly appreciated. Heres my situation, I have no idea where I am in this maze, but I need to move around and find my way back to the start. I was thinking of implementing a waypoint list of places i've been offset from my start at 0,0. This is a 2D cartesian plane. I've been given 2 properties, my translation speed from 0-1 and my rotation speed from -1 to 1. -1 is very left and +1 is very right. These are speed and not angles so thats where my problem lies. If I'm given 0 as a translation speed and 0.2 I will continually turn to my right at a slow speed. How do I figure out the offsets given these 2 variables? I can store it every time I take a 'step'. I just need to figure out the offsets in x and y terms given the translations and rotation speeds. And the rotation to get to those points. Any help is appreciated.

    Read the article

  • How do I know when to increase or decrease angle to get a specific angle?

    - by Thomas
    Hi. I am programming a game and I have come to a very hard spot. Basically I have a circle and I have 2 angles on this circle. Angle 1 (A) is a point I want angle 2 (B) to go to. During my game every frame I need to check weither or not to increase or decrease my angle value by a certain amount (speed) to eventually reach the first angle. My question is how do I do this? I tried doing this but I don't seem to be doing it right. bool increase = false; float B = [self radiansToDegrees:tankAngle]; float A = [self radiansToDegrees:tankDestinationAngle]; float newAngle = B; if(B < A) { float C = B - (360 - A); float D = A - B; if(C < D) increase = false; else increase = true; } else if(B A) { float C = B - A; float D = A - (360 - B); if(C < D) increase = false; else increase = true; } if(increase) { newAngle += 1.0; } else { newAngle -= 1.0; } if(newAngle 360.0) { newAngle = 0 + (newAngle - 360.0); } else if(newAngle < 0.0) { newAngle = 360 + newAngle; } if(newAngle == 0) newAngle = 360; newAngle = [self degreesToRadians:newAngle]; [self setTanksProperPositionRotation:newAngle]; The basic effect I am trying to achieve is when the user makes a new point, which would be angle 1, angle 2 would move towards angle 1 choosing the fastest direction. I think I have spent around 4 hours trying to figure this out.

    Read the article

  • Changing direction of rotation Pygame

    - by czl
    How would you change the direction of a rotating image/rect in Pygame? Applying positive and negative degree values works but it seems to only be able to rotate one direction throughout my window. Is there a way to ensure a change in direction of rotation? Perhaps change up rotation of a spinning image every 5 seconds, or if able to change the direction of the spin when hitting a X or Y axis. I've added some code below. It seems like switching movement directions is easy with rect.move_ip as long as I specify a speed and have location clause, it does what I want. Unfortunately rotation is't like that. Here I'l adding angles to make sure it spins, but no matter what I try, I'm unable to negate the rotation. def rotate_image(self): #rotate image orig_rect = self.image.get_rect() rot_image = pygame.transform.rotate(self.image, self.angle) rot_rect = orig_rect.copy() rot_rect.center = rot_image.get_rect().center rot_image = rot_image.subsurface(rot_rect).copy() return rot_image def render(self): self.screen.fill(self.bg_color) self.rect.move_ip(0,5) #Y axis movement at 5 px per frame self.angle += 5 #add 5 anglewhen the rect has not hit one of the window self.angle %= 360 if self.rect.left < 0 or self.rect.right > self.width: self.speed[0] = -self.speed[0] self.angle = -self.angle #tried to invert the angle self.angle -= 5 #trying to negate the angle rotation self.angle %= 360 self.screen.blit(self.rotate_image(),self.rect) pygame.display.flip() I would really like to know how to invert rotation of a image. You may provide your own examples.

    Read the article

  • Simulate Golf Game Strategy

    - by Mitchel Sellers
    I am working on what at best could be considered a "primitive" golf game, where after a certain bit of randomness is introduced I need to play out a hole of golf. The hole is static and I am not concerned about the UI aspect as I just have to draw a line on a graphic of the hole after the ball has been hit showing where it traveled. I'm looking for input on thoughts of how to manage the "logic" side of the puzzle, below are some of my thoughts on the matter, input, suggestions, or references are greatly appreciated. Map out the hole into an array with a specific amount of precision, noting the type of surface: out of bounds, fairway, rough, green, sand, water, and most important the hole. Map out "regions" and if the ball is contained inside one of these regions setup parameters for "maximum" angle of departure. (For example the first part of the hole the shot must be between certain angles Using the current placement of the ball, and the region contained in #2, define a routine to randomly select the shooting angle, and power then move the ball, adjust the trajectory and move again. I know this isn't the "most elegant" solution, but in reality, we are looking for a quick and dirty solution, as I just have to do this a few times, set it and forget it afterward. From a languages perspective I'll be using ASP.NET and C# to get this done.

    Read the article

  • Big Data – What is Big Data – 3 Vs of Big Data – Volume, Velocity and Variety – Day 2 of 21

    - by Pinal Dave
    Data is forever. Think about it – it is indeed true. Are you using any application as it is which was built 10 years ago? Are you using any piece of hardware which was built 10 years ago? The answer is most certainly No. However, if I ask you – are you using any data which were captured 50 years ago, the answer is most certainly Yes. For example, look at the history of our nation. I am from India and we have documented history which goes back as over 1000s of year. Well, just look at our birthday data – atleast we are using it till today. Data never gets old and it is going to stay there forever.  Application which interprets and analysis data got changed but the data remained in its purest format in most cases. As organizations have grown the data associated with them also grew exponentially and today there are lots of complexity to their data. Most of the big organizations have data in multiple applications and in different formats. The data is also spread out so much that it is hard to categorize with a single algorithm or logic. The mobile revolution which we are experimenting right now has completely changed how we capture the data and build intelligent systems.  Big organizations are indeed facing challenges to keep all the data on a platform which give them a  single consistent view of their data. This unique challenge to make sense of all the data coming in from different sources and deriving the useful actionable information out of is the revolution Big Data world is facing. Defining Big Data The 3Vs that define Big Data are Variety, Velocity and Volume. Volume We currently see the exponential growth in the data storage as the data is now more than text data. We can find data in the format of videos, musics and large images on our social media channels. It is very common to have Terabytes and Petabytes of the storage system for enterprises. As the database grows the applications and architecture built to support the data needs to be reevaluated quite often. Sometimes the same data is re-evaluated with multiple angles and even though the original data is the same the new found intelligence creates explosion of the data. The big volume indeed represents Big Data. Velocity The data growth and social media explosion have changed how we look at the data. There was a time when we used to believe that data of yesterday is recent. The matter of the fact newspapers is still following that logic. However, news channels and radios have changed how fast we receive the news. Today, people reply on social media to update them with the latest happening. On social media sometimes a few seconds old messages (a tweet, status updates etc.) is not something interests users. They often discard old messages and pay attention to recent updates. The data movement is now almost real time and the update window has reduced to fractions of the seconds. This high velocity data represent Big Data. Variety Data can be stored in multiple format. For example database, excel, csv, access or for the matter of the fact, it can be stored in a simple text file. Sometimes the data is not even in the traditional format as we assume, it may be in the form of video, SMS, pdf or something we might have not thought about it. It is the need of the organization to arrange it and make it meaningful. It will be easy to do so if we have data in the same format, however it is not the case most of the time. The real world have data in many different formats and that is the challenge we need to overcome with the Big Data. This variety of the data represent  represent Big Data. Big Data in Simple Words Big Data is not just about lots of data, it is actually a concept providing an opportunity to find new insight into your existing data as well guidelines to capture and analysis your future data. It makes any business more agile and robust so it can adapt and overcome business challenges. Tomorrow In tomorrow’s blog post we will try to answer discuss Evolution of Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

    Read the article

  • Microsoft TechEd 2010 - Day 2 @ Bangalore

    - by sathya
    Microsoft TechEd 2010 - Day 2 @ Bangalore Today is the day 2 @ Microsoft TechEd 2010. We had lot of technical sessions as usual there were many tracks going on side by side and I was attending the Web simplified track, Which comprised of the following sessions :   Developing a scalable Media Application using ASP.NET MVC - This was a kind of little advanced stuff. Anyways I couldn't understand much because this was not my piece of cake and I havent worked on this before ASP.Net MVC Unplugged - This was really great because this session covered from the basics of MVC showing what is Model,View and Controller and how it worked and the speaker went into the details of the same. Building RESTful Applications with the Open Data Protocol - There were some concepts explained about this from the basics on how to build RESTful Services and it went on till some advanced configurations of the same. Developing Scalable Web Applications with AppFabric Caching - This session showed about the integration of AppFabric with the .Net Web Applications. Instead of using Inproc Sessions, we can use this AppFabric as a substitute for Caching and outofProc Session Storage without writing code and doing a little bit of configurations which brings in High Scalability, performance to our applications. (But unfortunately there were no demos for this session ) Deep Dive : WCF RIA Services - This session was also an interactive one, in this the speaker presented from the basics of WCF and took a Book Store Application as a sample and explained all details concepts on linking with RIA Services   Apart from these sessions, in between there happened some small events in the breaks like Some discussions about Technology, Innovations Music Jokes Mimicry, etc. And on doing all these things, the developers were given some kool gifts / goodies like USBs, T-Shirts, etc. And today I got a chance to do the following certification : (70-562) Microsoft Certified Technology Specialist in .NET 3.5 Web Applications Since I already have an MCTS in .NET 2.0, I wanted to do an MCPD and for doing the same I was required to do an update to my MCTS with the .NET 3.5 framework and I did the same I cleared it and now am an MCTS in .NET 3.5 Web Apps And on doing this I got a T-Shirt and they gave something called Learning $ of worth 30$. And in various stalls for attending each quiz or some game or some referrals we got some Learning $ which we can redeem later based on our Total Learning $. I got 105 $ which i was able to redeem and got a Microsoft Learning BagPack, 1 free Microsoft certification offer, a laptop light and an e-learning content activated. And after all these sessions and small events, we had something called Demo Extravaganza like I mentioned yesterday. This was a great funfilled event with lot of goodies for the attendees. There were some lucky draw which enabled 2 attendees to get Netbooks (Sponsored by Intel) and 1 attendee to get X-box (Sponsored by Citrix). After Choosing the raffle in the lucky draw they kept it on a device called Microsoft Surface which is a kind of big touch screen device and on putting the raffle on that it detected the code of the attendee and said intelligently how many sessions that person has attended and if he has attended more than 5 he got a Netbook and this was coded by a guy called Imran. Apart from they showed demos on : Research by 2 Tamilnadu students from Krishna Arts and Science college, taken 1200 photographs of their college from different angles and put that up in Bing maps using silverlight and linked with Photosynth, which showed a 3d view of their college based on the photos they uploaded Reasearch by Microsoft on Panaramic HD views of the images. One young guy from Microsoft Research showed a demo of this on Srivilliputhur Andal Temple, in Tamil Nadu and its history with a panoramic view of the temple and the near by places with narration of the historical information on the same and with the videos embedded in it with high definition images which we can zoom to a very detailed level. Some Demo on a business app with Silverlight, Business Intelligence (BI) and maps integrated. It showed the sales of a particular product across locations. Some kool demos by 2 geeks who used Robots to show their development talents. 2 Robots fought with each other 2 Robots danced in sync for the A.R. Rehman song Humma Humma... A dream home project by Raman. He is currently using the same in his home too. Robots are controlling his home currently. They showed a video on this. Here are the list of activities that Robot does for him When he reads a book, robot automatically scans that and shows that image of that person in the screen (TV or comp) in front of him. It shows a wikipedia about that person. It says that person is not in linked in. do you want to add him If he sees an IPL Match news in the book and smiles it understands he is interested in that and opens a website related to that and shows the current game and the scorecard. It cooks for him It cleans the room for him whenever he leaves the house when he is doing something if some intruder comes inside his house his computer automatically switches his screen showing the video of the person coming inside. When he wakes up it automatically opens up the system, loads his mails and the news by the side, etc. Some Demos on Microsoft Pivot. This was there in livelabs but it is now available in getpivot.com its a pivoting of the pictorial data based on some categories and filters on the searches that we do. And finally on filling up some feedback forms we got T-Shirts and Microsoft Visual Studio 2010 Training Kit CDs. Whats more on TechEd??? Stay tuned!!! Will update you soon on the other happenings!! PS : I typed a lot of content for more than a hour but I pressed a backspace and it went to the previous page and all my content were lost and I was not able to retrieve the same and I typed everything again.

    Read the article

  • Most efficient way to implement delta time

    - by Starkers
    Here's one way to implement delta time: /// init /// var duration = 5000, currentTime = Date.now(); // and create cube, scene, camera ect ////// function animate() { /// determine delta /// var now = Date.now(), deltat = now - currentTime, currentTime = now, scalar = deltat / duration, angle = (Math.PI * 2) * scalar; ////// /// animate /// cube.rotation.y += angle; ////// /// update /// requestAnimationFrame(render); ////// } Could someone confirm I know how it works? Here what I think is going on: Firstly, we set duration at 5000, which how long the loop will take to complete in an ideal world. With a computer that is slow/busy, let's say the animation loop takes twice as long as it should, so 10000: When this happens, the scalar is set to 2.0: scalar = deltat / duration scalar = 10000 / 5000 scalar = 2.0 We now times all animation by twice as much: angle = (Math.PI * 2) * scalar; angle = (Math.PI * 2) * 2.0; angle = (Math.PI * 4) // which is 2 rotations When we do this, the cube rotation will appear to 'jump', but this is good because the animation remains real-time. With a computer that is going too quickly, let's say the animation loop takes half as long as it should, so 2500: When this happens, the scalar is set to 0.5: scalar = deltat / duration scalar = 2500 / 5000 scalar = 0.5 We now times all animation by a half: angle = (Math.PI * 2) * scalar; angle = (Math.PI * 2) * 0.5; angle = (Math.PI * 1) // which is half a rotation When we do this, the cube won't jump at all, and the animation remains real time, and doesn't speed up. However, would I be right in thinking this doesn't alter how hard the computer is working? I mean it still goes through the loop as fast as it can, and it still has render the whole scene, just with different smaller angles! So this a bad way to implement delta time, right? Now let's pretend the computer is taking exactly as long as it should, so 5000: When this happens, the scalar is set to 1.0: angle = (Math.PI * 2) * scalar; angle = (Math.PI * 2) * 1; angle = (Math.PI * 2) // which is 1 rotation When we do this, everything is timsed by 1, so nothing is changed. We'd get the same result if we weren't using delta time at all! My questions are as follows Mostly importantly, have I got the right end of the stick here? How do we know to set the duration to 5000 ? Or can it be any number? I'm a bit vague about the "computer going too quickly". Is there a way loop less often rather than reduce the animation steps? Seems like a better idea. Using this method, do all of our animations need to be timesed by the scalar? Do we have to hunt down every last one and times it? Is this the best way to implement delta time? I think not, due to the fact the computer can go nuts and all we do is divide each animation step and because we need to hunt down every step and times it by the scalar. Not a very nice DSL, as it were. So what is the best way to implement delta time? Below is one way that I do not really get but may be a better way to implement delta time. Could someone explain please? // Globals INV_MAX_FPS = 1 / 60; frameDelta = 0; clock = new THREE.Clock(); // In the animation loop (the requestAnimationFrame callback)… frameDelta += clock.getDelta(); // API: "Get the seconds passed since the last call to this method." while (frameDelta >= INV_MAX_FPS) { update(INV_MAX_FPS); // calculate physics frameDelta -= INV_MAX_FPS; } How I think this works: Firstly we set INV_MAX_FPS to 0.01666666666 How we will use this number number does not jump out at me. We then intialize a frameDelta which stores how long the last loop took to run. Come the first loop frameDelta is not greater than INV_MAX_FPS so the loop is not run (0 = 0.01666666666). So nothing happens. Now I really don't know what would cause this to happen, but let's pretend that the loop we just went through took 2 seconds to complete: We set frameDelta to 2: frameDelta += clock.getDelta(); frameDelta += 2.00 Now we run an animation thanks to update(0.01666666666). Again what is relevance of 0.01666666666?? And then we take away 0.01666666666 from the frameDelta: frameDelta -= INV_MAX_FPS; frameDelta = frameDelta - INV_MAX_FPS; frameDelta = 2 - 0.01666666666 frameDelta = 1.98333333334 So let's go into the second loop. Let's say it took 2(? Why not 2? Or 12? I am a bit confused): frameDelta += clock.getDelta(); frameDelta = frameDelta + clock.getDelta(); frameDelta = 1.98333333334 + 2 frameDelta = 3.98333333334 This time we enter the while loop because 3.98333333334 = 0.01666666666 We run update We take away 0.01666666666 from frameDelta again: frameDelta -= INV_MAX_FPS; frameDelta = frameDelta - INV_MAX_FPS; frameDelta = 3.98333333334 - 0.01666666666 frameDelta = 3.96666666668 Now let's pretend the loop is super quick and runs in just 0.1 seconds and continues to do this. (Because the computer isn't busy any more). Basically, the update function will be run, and every loop we take away 0.01666666666 from the frameDelta untill the frameDelta is less than 0.01666666666. And then nothing happens until the computer runs slowly again? Could someone shed some light please? Does the update() update the scalar or something like that and we still have to times everything by the scalar like in the first example?

    Read the article

  • Relative cam movement and momentum on arbitrary surface

    - by user29244
    I have been working on a game for quite long, think sonic classic physics in 3D or tony hawk psx, with unity3D. However I'm stuck at the most fundamental aspect of movement. The requirement is that I need to move the character in mario 64 fashion (or sonic adventure) aka relative cam input: the camera's forward direction always point input forward the screen, left or right input point toward left or right of the screen. when input are resting, the camera direction is independent from the character direction and the camera can orbit the character when input are pressed the character rotate itself until his direction align with the direction the input is pointing at. It's super easy to do as long your movement are parallel to the global horizontal (or any world axis). However when you try to do this on arbitrary surface (think moving along complex curved surface) with the character sticking to the surface normal (basically moving on wall and ceiling freely), it seems harder. What I want is to achieve the same finesse of movement than in mario but on arbitrary angled surfaces. There is more problem (jumping and transitioning back to the real world alignment and then back on a surface while keeping momentum) but so far I didn't even take off the basics. So far I have accomplish moving along the curved surface and the relative cam input, but for some reason direction fail all the time (point number 3, the character align slowly to the input direction). Do you have an idea how to achieve that? Here is the code and some demo so far: The demo: https://dl.dropbox.com/u/24530447/flash%20build/litesonicengine/LiteSonicEngine5.html Camera code: using UnityEngine; using System.Collections; public class CameraDrive : MonoBehaviour { public GameObject targetObject; public Transform camPivot, camTarget, camRoot, relcamdirDebug; float rot = 0; //---------------------------------------------------------------------------------------------------------- void Start() { this.transform.position = targetObject.transform.position; this.transform.rotation = targetObject.transform.rotation; } void FixedUpdate() { //the pivot system camRoot.position = targetObject.transform.position; //input on pivot orientation rot = 0; float mouse_x = Input.GetAxisRaw( "camera_analog_X" ); // rot = rot + ( 0.1f * Time.deltaTime * mouse_x ); // wrapAngle( rot ); // //when the target object rotate, it rotate too, this should not happen UpdateOrientation(this.transform.forward,targetObject.transform.up); camRoot.transform.RotateAround(camRoot.transform.up,rot); //debug the relcam dir RelativeCamDirection() ; //this camera this.transform.position = camPivot.position; //set the camera to the pivot this.transform.LookAt( camTarget.position ); // } //---------------------------------------------------------------------------------------------------------- public float wrapAngle ( float Degree ) { while (Degree < 0.0f) { Degree = Degree + 360.0f; } while (Degree >= 360.0f) { Degree = Degree - 360.0f; } return Degree; } private void UpdateOrientation( Vector3 forward_vector, Vector3 ground_normal ) { Vector3 projected_forward_to_normal_surface = forward_vector - ( Vector3.Dot( forward_vector, ground_normal ) ) * ground_normal; camRoot.transform.rotation = Quaternion.LookRotation( projected_forward_to_normal_surface, ground_normal ); } float GetOffsetAngle( float targetAngle, float DestAngle ) { return ((targetAngle - DestAngle + 180)% 360) - 180; } //---------------------------------------------------------------------------------------------------------- void OnDrawGizmos() { Gizmos.DrawCube( camPivot.transform.position, new Vector3(1,1,1) ); Gizmos.DrawCube( camTarget.transform.position, new Vector3(1,5,1) ); Gizmos.DrawCube( camRoot.transform.position, new Vector3(1,1,1) ); } void OnGUI() { GUI.Label(new Rect(0,80,1000,20*10), "targetObject.transform.up : " + targetObject.transform.up.ToString()); GUI.Label(new Rect(0,100,1000,20*10), "target euler : " + targetObject.transform.eulerAngles.y.ToString()); GUI.Label(new Rect(0,100,1000,20*10), "rot : " + rot.ToString()); } //---------------------------------------------------------------------------------------------------------- void RelativeCamDirection() { float input_vertical_movement = Input.GetAxisRaw( "Vertical" ), input_horizontal_movement = Input.GetAxisRaw( "Horizontal" ); Vector3 relative_forward = Vector3.forward, relative_right = Vector3.right, relative_direction = ( relative_forward * input_vertical_movement ) + ( relative_right * input_horizontal_movement ) ; MovementController MC = targetObject.GetComponent<MovementController>(); MC.motion = relative_direction.normalized * MC.acceleration * Time.fixedDeltaTime; MC.motion = this.transform.TransformDirection( MC.motion ); //MC.transform.Rotate(Vector3.up, input_horizontal_movement * 10f * Time.fixedDeltaTime); } } Mouvement code: using UnityEngine; using System.Collections; public class MovementController : MonoBehaviour { public float deadZoneValue = 0.1f, angle, acceleration = 50.0f; public Vector3 motion ; //-------------------------------------------------------------------------------------------- void OnGUI() { GUILayout.Label( "transform.rotation : " + transform.rotation ); GUILayout.Label( "transform.position : " + transform.position ); GUILayout.Label( "angle : " + angle ); } void FixedUpdate () { Ray ground_check_ray = new Ray( gameObject.transform.position, -gameObject.transform.up ); RaycastHit raycast_result; Rigidbody rigid_body = gameObject.rigidbody; if ( Physics.Raycast( ground_check_ray, out raycast_result ) ) { Vector3 next_position; //UpdateOrientation( gameObject.transform.forward, raycast_result.normal ); UpdateOrientation( gameObject.transform.forward, raycast_result.normal ); next_position = GetNextPosition( raycast_result.point ); rigid_body.MovePosition( next_position ); } } //-------------------------------------------------------------------------------------------- private void UpdateOrientation( Vector3 forward_vector, Vector3 ground_normal ) { Vector3 projected_forward_to_normal_surface = forward_vector - ( Vector3.Dot( forward_vector, ground_normal ) ) * ground_normal; transform.rotation = Quaternion.LookRotation( projected_forward_to_normal_surface, ground_normal ); } private Vector3 GetNextPosition( Vector3 current_ground_position ) { Vector3 next_position; // //-------------------------------------------------------------------- // angle = 0; // Vector3 dir = this.transform.InverseTransformDirection(motion); // angle = Vector3.Angle(Vector3.forward, dir);// * 1f * Time.fixedDeltaTime; // // if(angle > 0) this.transform.Rotate(0,angle,0); // //-------------------------------------------------------------------- next_position = current_ground_position + gameObject.transform.up * 0.5f + motion ; return next_position; } } Some observation: I have the correct input, I have the correct translation in the camera direction ... but whenever I attempt to slowly lerp the direction of the character in direction of the input, all I get is wild spin! Sad Also discovered that strafing to the right (immediately at the beginning without moving forward) has major singularity trapping on the equator!! I'm totally lost and crush (I have already done a much more featured version which fail at the same aspect)

    Read the article

  • Tiling rectangles seamlessly in WPF

    - by Joe White
    I want to seamlessly tile a bunch of different-colored Rectangles in WPF. That is, I want to put a bunch of rectangles edge-to-edge, and not have gaps between them. If everything is aligned to pixels, this works fine. But I also want to support arbitrary zoom, and ideally, I don't want to use SnapsToDevicePixels (because it would compromise quality when the image is zoomed way out). But that means my Rectangles sometimes render with gaps. For example: <Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Background="Black"> <Canvas SnapsToDevicePixels="False"> <Canvas.RenderTransform> <ScaleTransform ScaleX="0.5" ScaleY="0.5"/> </Canvas.RenderTransform> <Rectangle Canvas.Left="25" Width="100" Height="100" Fill="#CFC"/> <Rectangle Canvas.Left="125" Width="100" Height="100" Fill="#CCF"/> </Canvas> </Page> If the ScaleTransform's ScaleX is 1, then the Rectangles fit together seamlessly. When it's 0.5, there's a dark gray streak between them. I understand why -- the combined semi-transparent edge pixels don't combine to be 100% opaque. But I would like a way to fix it. I could always just make the Rectangles overlap, but I won't always know in advance what patterns they'll be in (this is for a game that will eventually support a map editor). Besides, this would cause artifacts around the overlap area when things were zoomed way in (unless I did bevel-cut angles on the underlapping portion, which is an awful lot of work, and still causes problems at corners). Is there some way I can combine these Rectangles into a single combined "shape" that does render without internal gaps? I've played around with GeometryDrawing, which does exactly that, but then I don't see a way to paint each RectangleGeometry with a different-colored brush. Are there any other ways to get shapes to tile seamlessly under an arbitrary transform, without resorting to SnapsToDevicePixels?

    Read the article

  • Is the design notion of layers contrived?

    - by Bruce
    Hi all I'm reading through Eric Evans' awesome work, Domain-Driven Design. However, I can't help feeling that the 'layers' model is contrived. To expand on that statement, it seems as if it tries to shoe-horn various concepts into a specific, neat model, that of layers talking to each other. It seems to me that the layers model is too simplified to actually capture the way that (good) software works. To expand further: Evans says: "Partition a complex program into layers. Develop a design within each layer that is cohesive and that depends only on the layers below. Follow standard architectural patterns to provide loose coupling to the layers above." Maybe I'm misunderstanding what 'depends' means, but as far as I can see, it can either mean a) Class X (in the UI for example) has a reference to a concrete class Y (in the main application) or b) Class X has a reference to a class Y-ish object providing class Y-ish services (ie a reference held as an interface). If it means (a), then this is clearly a bad thing, since it defeats re-using the UI as a front-end to some other application that provides Y-ish functionality. But if it means (b), then how is the UI any more dependent on the application, than the application is dependent on the UI? Both are decoupled from each other as much as they can be while still talking to each other. Evans' layer model of dependencies going one way seems too neat. First, isn't it more accurate to say that each area of the design provides a module that is pretty much an island to itself, and that ideally all communication is through interfaces, in a contract-driven/responsibility-driven paradigm? (ie, the 'dependency only on lower layers' is contrived). Likewise with the domain layer talking to the database - the domain layer is as decoupled (through DAO etc) from the database as the database is from the domain layer. Neither is dependent on the other, both can be swapped out. Second, the idea of a conceptual straight line (as in from one layer to the next) is artificial - isn't there more a network of intercommunicating but separate modules, including external services, utility services and so on, branching off at different angles? Thanks all - hoping that your responses can clarify my understanding on this..

    Read the article

  • Turtle Graphics as a Haskell Monad

    - by iliis
    I'm trying to implement turtle graphis in Haskell. The goal is to be able to write a function like this: draw_something = do fordward 100 right 90 forward 100 ... and then have it produce a list of points (maybe with additional properties): > draw_something (0,0) 0 -- start at (0,0) facing east (0 degrees) [(0,0), (0,100), (-100,100), ...] I have all this working in a 'normal' way, but I fail to implement it as a Haskell Monad and use the do-notation. The basic code: data State a = State (a, a) a -- (x,y), angle deriving (Show, Eq) initstate :: State Float initstate = State (0.0,0.0) 0.0 -- constrain angles to 0 to 2*pi fmod :: Float -> Float fmod a | a >= 2*pi = fmod (a-2*pi) | a < 0 = fmod (a+2*pi) | otherwise = a forward :: Float -> State Float -> [State Float] forward d (State (x,y) angle) = [State (x + d * (sin angle), y + d * (cos angle)) angle] right :: Float -> State Float -> [State Float] right d (State pos angle) = [State pos (fmod (angle+d))] bind :: [State a] -> (State a -> [State a]) -> [State a] bind xs f = xs ++ (f (head $ reverse xs)) ret :: State a -> [State a] ret x = [x] With this I can now write > [initstate] `bind` (forward 100) `bind` (right (pi/2)) `bind` (forward 100) [State (0.0,0.0) 0.0,State (0.0,100.0) 0.0,State (0.0,100.0) 1.5707964,State (100.0,99.99999) 1.5707964] And get the expected result. However I fail to implement this as an instance of Monad. instance Monad [State] where ... results in `State' is not applied to enough type arguments Expected kind `*', but `State' has kind `* -> *' In the instance declaration for `Monad [State]' And if I wrap the list in a new object data StateList a = StateList [State a] instance Monad StateList where return x = StateList [x] I get Couldn't match type `a' with `State a' `a' is a rigid type variable bound by the type signature for return :: a -> StateList a at logo.hs:38:9 In the expression: x In the first argument of `StateList', namely `[x]' In the expression: StateList [x] I tried various other versions but I never got it to run as I'd like to. What am I doing wrong? What do I understand incorrectly?

    Read the article

  • Why differs floating-point precision in C# when separated by parantheses and when separated by state

    - by Andreas Larsen
    I am aware of how floating point precision works in the regular cases, but I stumbled on an odd situation in my C# code. Why aren't result1 and result2 the exact same floating point value here? const float A; // Arbitrary value const float B; // Arbitrary value float result1 = (A*B)*dt; float result2 = (A*B); result2 *= dt; From this page I figured float arithmetic was left-associative and that this means values are evaluated and calculated in a left-to-right manner. The full source code involves XNA's Quaternions. I don't think it's relevant what my constants are and what the VectorHelper.AddPitchRollYaw() does. The test passes just fine if I calculate the delta pitch/roll/yaw angles in the same manner, but as the code is below it does not pass: X Expected: 0.275153548f But was: 0.275153786f [TestFixture] internal class QuaternionPrecisionTest { [Test] public void Test() { JoystickInput input; input.Pitch = 0.312312432f; input.Roll = 0.512312432f; input.Yaw = 0.912312432f; const float dt = 0.017001f; float pitchRate = input.Pitch * PhysicsConstants.MaxPitchRate; float rollRate = input.Roll * PhysicsConstants.MaxRollRate; float yawRate = input.Yaw * PhysicsConstants.MaxYawRate; Quaternion orient1 = Quaternion.Identity; Quaternion orient2 = Quaternion.Identity; for (int i = 0; i < 10000; i++) { float deltaPitch = (input.Pitch * PhysicsConstants.MaxPitchRate) * dt; float deltaRoll = (input.Roll * PhysicsConstants.MaxRollRate) * dt; float deltaYaw = (input.Yaw * PhysicsConstants.MaxYawRate) * dt; // Add deltas of pitch, roll and yaw to the rotation matrix orient1 = VectorHelper.AddPitchRollYaw( orient1, deltaPitch, deltaRoll, deltaYaw); deltaPitch = pitchRate * dt; deltaRoll = rollRate * dt; deltaYaw = yawRate * dt; orient2 = VectorHelper.AddPitchRollYaw( orient2, deltaPitch, deltaRoll, deltaYaw); } Assert.AreEqual(orient1.X, orient2.X, "X"); Assert.AreEqual(orient1.Y, orient2.Y, "Y"); Assert.AreEqual(orient1.Z, orient2.Z, "Z"); Assert.AreEqual(orient1.W, orient2.W, "W"); } } Granted, the error is small and only presents itself after a large number of iterations, but it has caused me some great headackes.

    Read the article

  • MVVM Binding Orthogonal Aspects in Views e.g. Application Settings

    - by chibacity
    I have an application which I am developing using WPF\Prism\MVVM. All is going well and I have some pleasing MVVM implementations. However, in some of my views I would like to be able to bind application settings e.g. when a user reloads an application, the checkbox for auto-scrolling a grid should be checked in the state it was last time the user used the application. My view needs to bind to something that holds the "auto-scroll" setting state. I could put this on the view-model, but applications settings are orthogonal to the purpose of the view-model. The "auto-scroll" setting is controlling an aspect of the view. This setting is just an example. There will be quite a number of them and splattering my view-models with properties to represent application settings (so I can bind them) feels decidedly yucky. One view-model per view seems to be de rigeuer... What is best\usual practice here? Splatter my view-models with application settings? Have multiple view-models per view so settings can be represented in their own right? Split views so that controls can bind to an ApplicationSettingsViewModel? = too many views? Something else? Edit 1 To add a little more context, I am developing a UI with a tabbed interface. Each tab will host a single widget and there a variety of widgets. Each widget is a Prism composition of individual views. Some views are common amongst widgets e.g. a file picker view. Whilst each widget is composed of several views, as a whole, conceptually a widget has a single set of user settings e.g. last file selected, auto-scroll enabled, etc. These need to be persisted and retrieved\applied when the application starts again, and the widget views are created. My question is focused on the fact that conceptually a widget has a single set of user settings which is at right-angles to the fact that a widget consists of many views. Each view in the widget has it's own view-model (which works nicely and logically) but if I stick to a one view-model per view, I would have to splatter each view-model with user settings appropriate to it. This doesn't sound right ?!?

    Read the article

< Previous Page | 10 11 12 13 14 15 16  | Next Page >