Search Results

Search found 5070 results on 203 pages for 'algorithm'.

Page 131/203 | < Previous Page | 127 128 129 130 131 132 133 134 135 136 137 138  | Next Page >

• How do one improve him/her problem-solving ability ?

  - by gcc

  How can one improve him/her problem-solving ability? Every one says same thing "a real programmer knows how to handle real problem", but they forget how they learn this ability, or where (I know in school, no one gives us any ability, of course in my opinion). If you have any idea except above ones, feel free when you give your advice solve more problems do more exercises, write code, search google then write more ... For me, my question is like "Use complex/known library instead of using your own." In other words,t I want your presonal experience, book recommendation, web page on problem solving. Moreover, look your problem-solving method and give us your personal ability as if it is an algorithm

  Read the article

• Drawing territories border in 2d map

  - by Gabriel A. Zorrilla

  I'm programming a little web strategy game. In the country map I pretend to display each country with a national color. The issue is how to render the borders in a simple and efficient way. Right now I'm planning to set a field to each tile called "border" with values from 0 to 8. The algorithm would check for EVERY tile is its adjacent has a different "owner". If the tile is inside the territory, the border value would be 0, because would not have adjacent any tile with different owner, if not, would vary between 1 (north) clockwise to 9 (north-west) and then draw the border. I find this simple but too processor-intensive. Are there any other "pro" choices to render territories borders?

  Read the article

• Raycasting tutorial / vector math question

  - by mattboy

  I'm checking out this nice raycasting tutorial at http://lodev.org/cgtutor/raycasting.html and have a probably very simple math question. In the DDA algorithm I'm having trouble understanding the calcuation of the deltaDistX and deltaDistY variables, which are the distances that the ray has to travel from 1 x-side to the next x-side, or from 1 y-side to the next y-side, in the square grid that makes up the world map (see below screenshot). In the tutorial they are calculated as follows, but without much explanation: //length of ray from one x or y-side to next x or y-side double deltaDistX = sqrt(1 + (rayDirY * rayDirY) / (rayDirX * rayDirX)); double deltaDistY = sqrt(1 + (rayDirX * rayDirX) / (rayDirY * rayDirY)); rayDirY and rayDirX are the direction of a ray that has been cast. How do you get these formulas? It looks like pythagorean theorem is part of it, but somehow there's division involved here. Can anyone clue me in as to what mathematical knowledge I'm missing here, or "prove" the formula by showing how it's derived?

  Read the article

• Convert DVD to MKV (et al) without transcoding/recompression

  - by Oli

  Like a lot of people, I have a lot of DVDs. But we also have a stupid amount of disk space and a media centre (Boxee) so the DVDs are getting less and less use. It would be nice to convert our DVDs into something more relevant to our needs. I've dabbled with DVD ripping before but whereas I'd usually transcode down to a smaller picture size with a better video compression algorithm, this takes a silly amount of time. I don't have a couple of hours available for each disk. (Sidebar: is there dedicated, Linux-friendly hardware to improve h264 encoding performance?) So I was wondering if there's anything that take the DVD filesystem, De-CSS it, and then stitch together any the VOBs that make up the main part of the film and package that up in a wrapping format like MKV. A bonus would be if it could grab the subtitles and stick them in too but that's not a requirement as Boxee can grab the subtitles online if it needs to.

  Read the article

• Predicting advantages of database denormalization

  - by Janus Troelsen

  I was always taught to strive for the highest Normal Form of database normalization, and we were taught Bernstein's Synthesis algorithm to achieve 3NF. This is all very well and it feels nice to normalize your database, knowing that fields can be modified while retaining consistency. However, performance may suffer. That's why I am wondering whether there is any way to predict the speedup/slowdown when denormalizing. That way, you can build your list of FD's featuring 3NF and then denormalize as little as possible. I imagine that denormalizing too much would waste space and time, because e.g. giant blobs are duplicated or it because harder to maintain consistency because you have to update multiple fields using a transaction. Summary: Given a 3NF FD set, and a set of queries, how do I predict the speedup/slowdown of denormalization? Link to papers appreciated too.

  Read the article

• Is running "milli"-benchmarks a good idea?

  - by Konstantin Weitz

  I just came across the Caliper project and it looks very nice. Reading the introduction to microbenchmarks, one gets the feeling that the developers would not suggest to use the framework if the benchmark takes longer than a second or so. I looked at the code and it looks like a RuntimeOutOfRangeException is actually thrown if a scenario takes longer than 10s to execute. Could you explain to me what the problems are with running larger benchmarks? My motivation for using Caliper was to compare two join-algorithm implementations. Those will definitely run for quite some time and will do some disk IO, yet running the entire database would make it hard to do the comparison, because the configuration of the algorithms and the visualization of the results would be a pain.

  Read the article

• How to detect two moving shapes overlapped?

  - by user1389813

  Given a list of circles with its coordinates (x and y) that are moving every second in different direction (South-East, South-West, North-East and North-West), and the circle will change direction if it hits the wall sort of like bouncing, so how do we detect if any of them collide or overlap with each other ? I am not sure if we can use some data structures like a Binary Search Tree because since all the coordinates vary every seconds, so the tree will have to re-build accordingly. Or can we use Vertical Sweep Line Algorithm each time ? Any ideas on how to do this in a efficient way ?

  Read the article

• How will Quantum computing affect us?

  - by CiscoIPPhone

  I am interested in quantum computing, but have not studied it in depth. Things like Shor's algorithm intrigue me. My question is: If quantum computing took off in a big way (i.e. functional quantum home computers were available) how would it affect us programmers and software developers? Would we have to learn how to make use of superposition and entanglement - would it change how we write algorithms? Would more mathematical programmers be required/would we need new skills? Would it change nothing at all from our perspective (i.e. would it be abstracted)? Your opinion is welcome.

  Read the article

• Friendly URLs: is there a max length for search engines?

  - by Olivier Pons

  People from stackoverflow have been working closely with google team to help them make the panda algorithm more efficient, so I guess they've learned a lot from the google team. Thus they may have done very clever friendly URLs to maximize the page rank. I've seen from time to time very long URLs (can't find where) in stackoverflow, but after a certain "amount" of character there were only numbers, kind of "ok passed this length, SEOs will ignore this so let's put only numbers". I've done a huge work on my framework to make very friendly URLs, and my website can come up with URLs like: http://www.mysite.fr/recherche/region/provence-alpes-cote-d-azur/departement/bouches-du-rhone/categorie-de-metiers/paramedical/ It's very long and I'm wondering if the previous URL won't be mixed with, say, this one: http://www.mysite.fr/recherche/region/provence-alpes-cote-d-azur/departement/bouches-du-rhone/categorie-de-metiers/art/

  Read the article

• Should pathfinder in A* hold closedSet and openedSet or each object should hold its sets?

  - by Patryk

  I am about to implement A* pathfinding algorithm and I wonder how should I implement this - from the point of view of architecture. I have the pathfinder as a class - I think I will instantiate only one object of this class (or maybe make it a Singleton - this is not so important). The hardest part for me is whether the closedSet and openedSet should be attached to objects that can find the path for them or should be stored in pathfinder class ? I am opened to any hints and critique whatsoever. What is the best practice considering pathfinding in terms of design ?

  Read the article

• Convert DVD to MKV (et al) without transcoding/recompression

  - by Oli

  Like a lot of people, I have a lot of DVDs. But we also have a stupid amount of disk space and a media centre (Boxee) so the DVDs are getting less and less use. It would be nice to convert our DVDs into something more relevant to our needs. I've dabbled with DVD ripping before but whereas I'd usually transcode down to a smaller picture size with a better video compression algorithm, this takes a silly amount of time. I don't have a couple of hours available for each disk. (Sidebar: is there dedicated, Linux-friendly hardware to improve h264 encoding performance?) So I was wondering if there's anything that take the DVD filesystem, De-CSS it, and then stitch together any the VOBs that make up the main part of the film and package that up in a wrapping format like MKV. A bonus would be if it could grab the subtitles and stick them in too but that's not a requirement as Boxee can grab the subtitles online if it needs to.

  Read the article

• How to achieve a Gaussian Blur effect for shadows in LWJGL/Slick2D?

  - by user46883

  I am currently trying to implement shadows into my game, and after a lot of searching in the interwebs I came to the conclusion that drawing hard edged shadows to a low resolution pass combined with a Gaussian blur effect would fit best and make a good compromise between performance and looks - even though theyre not 100% physically accurate. Now my problem is, that I dont really know how to implement the Gaussian blur part. Its not difficult to draw shadows to a low resolutions buffer image and then stretch it which makes it more smooth, but I need to add the Gaussian blur effect. I have searched a lot on that and found some approachs for GLSL, some even here, but none of them really helped it. My game is written in Java using Slick2D/LWJGL and I would appreciate any help or approaches for an algorithm or maybe even an existing library to achieve that effect. Thanks for any help in advance.

  Read the article

• How can I generate a 2d navigation mesh in a dynamic environment at runtime?

  - by Stephen

  So I've grasped how to use A* for path-finding, and I am able to use it on a grid. However, my game world is huge and I have many enemies moving toward the player, which is a moving target, so a grid system is too slow for path-finding. I need to simplify my node graph by using a navigational mesh. I grasp the concept of "how" a mesh works (finding a path through nodes on the vertices and/or the centers of the edges of polygons). My game uses dynamic obstacles that are procedurally generated at run-time. I can't quite wrap my head around how to take a plane that has multiple obstacles in it and programatically divide the walkable area up into polygons for the navigation mesh, like the following image. Where do I start? How do I know when a segment of walk-able area is already defined, or worse, when I realize I need to subdivide a previously defined walk-able area as the algorithm "walks" through the map? I'm using javascript in nodejs, if it matters.

  Read the article

• Is finding graph minors without single node pinch points possible?

  - by Alturis

  Is it possible to robustly find all the graph minors within an arbitrary node graph where the pinch points are generally not single nodes? I have read some other posts on here about how to break up your graph into a Hamiltonian cycle and then from that find the graph minors but it seems to be such an algorithm would require that each "room" had "doorways" consisting of single nodes. To explain a bit more a visual aid is necessary. Lets say the nodes below are an example of the typical node graph. What I am looking for is a way to automatically find the different colored regions of the graph (or graph minors)

  Read the article

• Efficient way to sort large set of numbers

  - by 7Aces

  I have to sort a set of 100000 integers as a part of a programming Q. The time limit is pretty restrictive, so I have to use the most time-efficient approach possible. My current code - #include<cstdio> #include<algorithm> using namespace std; int main() { int n,d[100000],i; for(i=0;i<n;++i) { scanf("%d",&d[i]); } sort(d,d+n); .... } Would this approach be more efiicient? int main() { int n,d[100000],i; for(i=0;i<n;++i) { scanf("%d",&d[i]); sort(d,d+i+1); } .... } What is the most efficient way to sort a large dataset? Note - Not homework...

  Read the article

• How should I replan A*?

  - by Gregory Weir

  I've got a pathfinding boss enemy that seeks the player using the A* algorithm. It's a pretty complex environment, and I'm doing it in Flash, so the search can get a bit slow when it's searching over long distances. If the player was stationary, I could just search once, but at the moment I'm searching every frame. This takes long enough that my framerate is suffering. What's the usual solution to this? Is there a way to "replan" A* without redoing the entire search? Should I just search a little less often (every half-second or second) and accept that there will be a little inaccuracy in the path?

  Read the article

• Unity Dash/Lens - Auto-completion based on recent search strings

  - by Anant

  Sometimes, I find myself typing the same (or quite similar) search strings inside a Unity Lens. So, I thought whether it's possible for the Lens to remember previous searches, and provide a drop-down menu of possible suggestions (based on the past) when I start typing my new query. With Lenses for sites like Wikipedia and DuckDuckGo, the search strings are getting longer, and this feature would lend a helping hand in filling out queries faster. This could be something applicable to all Lenses, with later versions allowing individual Lenses to run their own auto-completion algorithm.

  Read the article

• A* Jump Point Search - how does pruning really work?

  - by DeadMG

  I've come across Jump Point Search, and it seems pretty sweet to me. However, I'm unsure as to how their pruning rules actually work. More specifically, in Figure 1, it states that we can immediately prune all grey neighbours as these can be reached optimally from the parent of x without ever going through node x However, this seems somewhat at odds. In the second image, node 5 could be reached by first going through node 7 and skipping x entirely through a symmetrical path- that is, 6 -> x -> 5 seems to be symmetrical to 6 -> 7 -> 5. This would be the same as how node 3 can be reached without going through x in the first image. As such, I don't understand how these two images are not entirely equivalent, and not just rotated versions of each other. Secondly, I'd like to understand how this algorithm could be generalized to a three-dimensional search volume.

  Read the article

• Reverse horizontal and vertical for a HTML table

  - by porton

  There is a two-dimensional array describing a HTML table. Each element of the array consists of: the cell content rowspan colspan Every row of this two dimensional array corresponds to <td> cells of a <tr> of the table which my software should generate. I need to "reverse" the array (interchange vertical and horizontal direction). Insofar I considered algorithm based on this idea: make a rectangular matrix of the size of the table and store in every element of this matrix the corresponding index of the element of the above mentioned array. (Note that two elements of the matrix may be identical due rowspan/colspan.) Then I could use this matrix to calculate rowspan/colspan for the inverted table. But this idea seems bad for me. Any other algorithms? Note that I program in PHP.

  Read the article

• How does one improve one's problem-solving ability?

  - by gcc

  How can one improve one's problem-solving ability? Everyone says same thing: "a real programmer knows how to handle real problem." But they forget how they learn this ability, or where (I know in school, no one gives us any ability, of course in my opinion). If you have any idea except above ones, feel free when you give your advice solve more problems do more exercises, write code, search google then write more ... For me, my question is like "use complex/known library instead of using your own." In other words, I want your personal experience, book recommendation, webpage on problem solving. Moreover, look your problem-solving method and give us your personal ability as if it is an algorithm

  Read the article

• Why is it impossible to produce truly random numbers?

  - by Vinoth Kumar

  I was trying to solve a hobby problem that required generating a million random numbers. But I quickly realized, it is becoming difficult to make them unique. I picked up Algorithm Design Manual to read about random number generation. It has the following paragraph that I am fully not able to understand. Unfortunately, generating random numbers looks a lot easier than it really is. Indeed, it is fundamentally impossible to produce truly random numbers on any deterministic device. Von Neumann [Neu63] said it best: “Anyone who considers arithmetical methods of producing random digits is, of course, in a state of sin.” The best we can hope for are pseudo-random numbers, a stream of numbers that appear as if they were generated randomly. Why is it impossible to produce truly random numbers in any deterministic device? What does this sentence mean?

  Read the article

• How can Swift be so much faster than Objective-C?

  - by Yellow

  Apple launched its new programming language Swift today. In the presentation, they made some performance comparisons between Objective-C and Python. The following is a picture of one of their slides, of a comparison of those three languages performing some complex object sort: There was an even more incredible graph about a performance comparison working on some encryption algorithm. Obviously this is a marketing talk, and they didn't go into detail on how this was implemented in each. I leaves me wondering though: how can a new programming language be so much faster? In this example, surely you just have a bad Objective-C compiler or you're doing something in a less efficient way? How else would you explain a 40% performance increase? I understand that garbage collection/automated reference control might produce some additional overhead, but this much?

  Read the article

• How do I detect multiple sprite collisions when there are >10 sprites?

  - by yao jiang

  I making a small program to animate the astar algorithm. If you look at the image, there are lots of yellow cars moving around. Those can collide at any moment, could be just one or all of them could just stupidly crash into each other. How do I detect all of those collisions? How do I find out which specific car has crash into which other car? I understand that pygame has collision function, but it only detects one collision at a time and I'd have to specify which sprites. Right now I am just trying to iterate through each sprite to see if there is collision: for car1 in carlist: for car2 in carlist: collide(car1, car2); This can't be the proper way to do it, if the car list goes to a huge number, a double loop will be too slow.

  Read the article

• How to credit other authors in an open source project

  - by erik

  I have a pet project that I am planning to release as open source at some point in the not-too-distant future. A couple of the files use or are mostly code that was taken from a project released under the New BSD License. While I have changed it to fit my needs and added some small stuff, the algorithm and the functionality is basically exactly the same. I want to make sure that the author of the code gets credit and that the license is not broken, but I also want to make the reader aware that this is not the code as it was orignally released. How should I approach this? Should I isolate the code as much as possible and just retain the original license? Maybe put all the files that contain foreign code in their own folder and add a readme explaining what has been added/removed? There must have been tons of projects using other open source code. What is the standard approach to this?

  Read the article

• How does bing-bot( is that the right spider-name? ) and googlebot interpret 301 redirect?

  - by jbcurtin

  I've been looking for documentation on how the Microsoft and Google bots interpret 301 redirects. It seems that google-bot stores documents on a url based index system. But I haven't been able to figure out how bing works. Should I assume that they are still working towards coping everyone else and assume they use an algorithm close to google? Is it best to just forward a page to a new location via Javascript? I think this might be a blackhat trick, but how would I tell the bots that it's not? Is 301 redirect my best option and I just have to bit the bullet because said pages are no longer in existence? What other options do I have that I might not be aware of?

  Read the article

< Previous Page | 127 128 129 130 131 132 133 134 135 136 137 138  | Next Page >