efficient storage - Page 254

When can a freely moving sphere escape from a ‘cage’ defined by a set of impassible coordinates?

- by RGrey

Hopefully there are some computational geometry folks here who can help me out with the following problem - Please imagine that I take a freely moving ball in 3-space and create a 'cage' around it by defining a set of impassible coordinates, Sc (i.e. points in 3-space that no part of the diffusing ball is allowed to overlap). These points reside within the volume, V(cage), of some larger sphere, where V(cage) V(ball). Provided the set of impassible coordinates, Sc, is there a computationally efficient and/or nice way to determine if the ball can ever escape the cage?

Read the article

code throws std::bad_alloc, not enough memory or can it be a bug?

- by Andreas

I am parsing using a pretty large grammar (1.1 GB, it's data-oriented parsing). The parser I use (bitpar) is said to be optimized for highly ambiguous grammars. I'm getting this error: 1terminate called after throwing an instance of 'std::bad_alloc' what(): St9bad_alloc dotest.sh: line 11: 16686 Aborted bitpar -p -b 1 -s top -u unknownwordsm -w pos.dfsa /tmp/gsyntax.pcfg /tmp/gsyntax.lex arbobanko.test arbobanko.results Is there hope? Does it mean that it has ran out of memory? It uses about 15 GB before it crashes. The machine I'm using has 32 GB of RAM, plus swap as well. It crashes before outputting a single parse tree. The parser is an efficient CYK chart parser using bit vector representations; I presume it is already near the limit of memory efficiency. If it really requires too much memory I could sample from the grammar rules, but this will decrease parse accuracy of course.

Read the article

Strategy in storing ad-hoc numbers/constants?

- by Jiho Han

I have a need to store a number of ad-hoc figures and constants for calculation. These numbers change periodically but they are different type of values. One might be a balance, a money amount, another might be an interest rate, and yet another might be a ratio of some kind. These numbers are then used in a calculation that involve other more structured figures. I'm not certain what the best way to store these in a relational DB is - that's the choice of storage for the app. One way, I've done before, is to create a very generic table that stores the values as text. I might store the data type along with it but the consumer knows what type it is so, in situations I didn't even need to store the data type. This kind of works fine but I am not very fond of the solution. Should I break down each of the numbers into specific categories and create tables that way? For example, create Rates table, and Balances table, etc.?

Read the article

Erlang bit indexing

- by GTDev

I am currently trying to learn erlang and what I am trying to do is to perform an operation on specific indices of an array stored in a bit array or int. If there is a 0 in a position, the index into the array at that position is not used. So envision the following: Example the array is: [1, 3, 5, 42, 23] My bit array is: 21 = 10101 in binary so I'm using indicies 1,3,5 so I'm calling a function on [1, 5, 23] my function is of the form my_function(Array, BitArray) -> SubArray = get_subarray_from_bitarray(Array, BitArray), process_subarray(SubArray). And I need help with the get_subarray_from_bitarray(). I know erlang has special syntax around bit strings (something like <<) so is there an efficient way of indexing into the bit array to get the indicies?

Read the article

Complicated MySQL query?

- by Scott

I have two tables: RatingsTable that contains a ratingname and a bit whether it is a positive or negative rating: Good 1 Bad 0 Fun 1 Boring 0 FeedbackTable that contains feedback on things...the person rating, the rating and the thing rated. The feedback can be determined if it's a positive or negative rating based on RatingsTable. Jim Chicken Good Jim Steak Bad Ted Waterskiing Fun Ted Hiking Fun Nancy Hiking Boring I am trying to write an efficient MySQL query for the following: On a page, I want to display the the top 'things' that have the highest proportional positive ratings. I want to be sure that the items from the feedback table are unique...meaning, that if Jim has rated Chicken Good 20 times...it should only be counted once. At some point I will want to require a minimum number of ratings (at least 10) to be counted for this page as well. I'll want to to do the same for highest proportional negative ratings, but I am sure I can tweak the one for positive accordingly.

Read the article

Question about AJAX

- by Doug

Read the article

SoundPool.load() and FileDescriptor from file

- by Hans

I tried using the load function of the SoundPool that takes a FileDescriptor, because I wanted to be able to set the offset and length. The File is not stored in the Ressources but a file on the storage card. Even though neither the load nor the play function of the SoundPool throw any Exception or print anything to the console, the sound is not played. Using the same code, but use the file path string in the SoundPool constructor works perfectly. This is how I have tried the loading (start equals 0 and length is the length of the file in miliseconds): FileInputStream fileIS = new FileInputStream(new File(mFile)); mStreamID = mSoundPool.load(fileIS.getFD(), start, length, 0); mPlayingStreamID = mSoundPool.play(mStreamID, 1f, 1f, 1, 0, 1f); If I would use this, it works: mStreamID = mSoundPool.load(mFile, 0); mPlayingStreamID = mSoundPool.play(mStreamID, 1f, 1f, 1, 0, 1f); Any ideas anyone? Thanks

Read the article

Get enum by it's inner field

- by zeroed

Hi! Have enum with inner fields, kind of map. Now I need to get enum by it's inner field. Wrote this: package test; /** * Test enum to test enum =) */ public enum TestEnum { ONE(1), TWO(2), THREE(3); private int number; TestEnum(int number) { this.number = number; } public TestEnum findByKey(int i) { TestEnum[] testEnums = TestEnum.values(); for (TestEnum testEnum : testEnums) { if (testEnum.number == i) { return testEnum; } } return null; } } But it's not very efficient to look up through all enums each time I need to find appropriate instance. Is there any other way to do the same?

Read the article

Is closing/disposing an SqlDataReader needed if you are already closing the sqlconnection?

- by Brian

I noticed This question, but my question is a bit more specific. Is there any advantage to using using (SqlConnection conn = new SqlConnection(conStr)) { using (SqlCommand command = new SqlCommand()) { // dostuff } } instead of using (SqlConnection conn = new SqlConnection(conStr)) { SqlCommand command = new SqlCommand(); // dostuff } Obviously it does matter run more than one command with the same connection, since closing an SqlDataReader is more efficient than closing and reopening a connection (calling conn.Close();conn.Open(); will also free up the connection). I see many people insist that failure to close the DataReader means leaving open connection resources around, but doesn't that only apply if you don't close the connection?

Read the article

Zend_Session: unserialize session data

- by takeshin

I'm using session SaveHandler to persist session data in the database. Sample session_data column from the database: Messenger|a:1:{s:13:"page_messages";a:0:{}}userSession|a:1:{s:7:"referer";s:32:"http://cms.dev/user/profile/view";}Zend_Auth|a:1:{s:7:"storage";O:19:"User_Model_Identity":3:{s:2:"id";s:1:"1";s:8:"username";s:13:"administrator";s:4:"slug";s:13:"administrator";}} I want to delete Zend_Auth object from this session data. How can I unserialize those objects and remove object I need? I suspect, that I don't have to write my custom parser, that Zend_Session already has a method to do this. I have tried different combinations of unserialize but it still returns false. I'm using autoloader from ZF 1.10.2 and Doctrine 1.2

Read the article

What is the best way to convert a hexidecimal string to a byte array (.NET)?

- by Robert Wagner

I have a hexidecimal string that I need to convert to a byte array. The best way (ie efficient and least code) is: string hexstr = "683A2134"; byte[] bytes = new byte[hexstr.Length/2]; for(int x = 0; x < bytes.Length; x++) { bytes[x] = Convert.ToByte(hexstr.Substring(x * 2, 2), 16); } In the case where I have a 32bit value I can do the following: string hexstr = "683A2134"; byte[] bytes = BitConverter.GetBytes(Convert.ToInt32(hexstr, 16)); However what about in the general case? Is there a better built in function, or a clearer (doesn't have to be faster, but still performant) way of doing this? I would prefer a built in function as there seems to be one for everything (well common things) except this particular conversion.

Read the article

[C++] instantiating bitset using hex character.

- by bndz

Hey, I'm trying to figure out how to instantiate a 4 bit bitset based on a hex character. For instance, If I have a character with value 'F', I want to create a bitset of size 4 initialized to 1111 or if it is A, i want to initialize it to 1010. I could use a bunch of if statements like so: fn(char c) { bitset<4 temp; if(c == 'F') temp.set(); //... if(c == '9') { temp.set(1); temp.set(3); } //... } This isn't efficient, is there a way of easily converting the string to a decimal integer and constructing the bitset using the last 4 bits of the int? Thanks for any help.

Read the article

non-servlet JSP

- by h2g2java

I realise there are EL and near EL frameworks like StringTemplate, JUEL, Velocity, etc. However, I am not asking for list of alternatives to JSTL/EL. I came across a package more than a year ago, someone who wrote a util that emulates the functionality of JSP for non-servlet env, i.e., JSP composition which does not need a "servlet container" to function. I ignored it and now I think it would be helpful to me and I need help to recall what it is. My actual motivation is similar to what StringTemplate, JUEL, Velocity would offer to help me compose SQL blocks, HTML blocks but I am thinking that JSPs are precompiled into bytecode and JSPs are more run-time efficient since run-time parsing is done no more than once. So actually, recommendation for alternatives would be acceptable as long as the templates are precompiled into bytecode. But I still prefer the JSP emulator.

Read the article

How to efficiently replace characters in XML document in Java?

- by Pregzt

I'm looking for a neat and efficient way to replace characters in XML document. There is a replacement table defined for almost 12.000 UTF-8 characters, most of them are to be replaced by single characters, but some must be replaced by two or even three characters (e.g. Greek theta should become TH). The documents can be bulky (100MB+). How to do it in Java? I came up with the idea of using XSLT, but I'm not too sure if this is the best option.

Read the article

Copying a 14bit grayscale image (saved in long[]) to a pictureBox

- by Itsik

My camera gives me 14bit grayscale images, but the API's function returns a long* to the image data. (so i'm assuming 4 bytes for each pixel) My application is written in C++/CLI, and the pictureBox is of .NET type. I am currently using the BitmapData.LockBits() mechanism to gain pointer access to the image data, and using memcpy(bmpData.Scan0.ToPointer(), imageData, sizeof(long)*height*width) to copy the image data to the Bitmap. For now, the only PixelFormat that is working is 32bit RGB, and the image appears in shades of blue with contours. Trying to initialize the Bitmap as 16bppGrayscale isn't working. I would ideally want to cast the array from long to word and using a 16bit format (hoping the the 14bit data will be displayed properly) but I'm not sure if this works. Also, I don't want to iterate over the image data, so finding the min/max and then histogram stretching to [0..255] isnt an option for me (the display must be as efficient as possible) Thanks

Read the article

Conceptual question about NSAutoreleasePools

- by ryyst

In my Cocoa program, wouldn't a really simple way of dealing with autoreleased objects be to just create a timer object inside the app delegate that calls the following method e.g. every 10 seconds: if (pool) { // Release & drain the current pool to free the memory. [pool release]; } // Create a new pool. pool = [[NSAutoreleasePool alloc] init]; The only problems I can imagine are: 1) If the above code runs in a separate thread, an object might get autoreleased between the release call to the old pool and the creation of the new pool - that seems highly unlikely though. 2) It's obviously not that efficient, because the pool might get released if there's nothing in it. Likewise, in the 10 second gap, many many objects might be autoreleased, causing the pool to grow a lot. Still, the above solution seems pretty suitable to small and simple projects. Why doesn't anybody use it? What's the best practice of using NSAutoreleasePools?

Read the article

.NET --- Textbox control - wait till user is done typing

- by Cj Anderson

Greetings all, Is there a built in way to know when a user is done typing into a textbox? (Before hitting tab, Or moving the mouse) I have a database query that occurs on the textchanged event and everything works perfectly. However, I noticed that there is a bit of lag of course because if a user is quickly typing into the textbox the program is busy doing a query for each character. So what I was hoping for was a way to see if the user has finished typing. So if they type "a" and stop then an event fires. However, if they type "all the way" the event fires after the y keyup. I have some ideas floating around my head but I'm sure they aren't the most efficient. Like measuring the time since the last textchange event and if it was than a certain value then it would proceed to run the rest of my procedures. let me know what you think. Language: VB.NET Framework: .Net 2.0 --Edited to clarify "done typing"

Read the article

Adding items to Model Collection in ASP.NET MVC

- by Stacey

In an ASP.NET MVC application where I have the following model.. public class EventViewModel { public Guid Id { get; set; } public List<Guid> Attendants { get; set; } } passed to a view... public ActionResult Create(EventViewModel model) { // ... } I want to be able to add to the "Attendants" Collection from the View. The code to add it works just fine - but how can I ensure that the View model retains the list? Is there any way to do this without saving/opening/saving etc? I am calling my addition method via jQuery $.load. public void Insert(Guid attendant) { // add the attendant to the attendees list of the model - called via $.load } I would also like to add there is no database. There is no storage persistence other than plain files.

Read the article

Django - Tips to avoid repeating code in views

- by D Roddis

I'm moving from a PHP background into Django development via python, mostly for the sake of tackling a MVC (or MVT) that I feel makes the most sense, although in this pattern I've started to notice a lot of repeated code in my views. For example, when logged in I have information regarding the user that I would like to appear on every page, although when using render_to_response and in every view this is required I have to grab the information and pass it to the render_to_response function. I'm wondering what would be the most efficient way to cut down on the duplicate code which would in essence be required in all views in a particular app. Thanks in advance.

Read the article

set / line intersection solution

- by Xavier

I have two lists in python and I want to know if they intersect at the same index. Is there a mathematical way of solving this? For example if I have [9,8,7,6,5] and [3,4,5,6,7] I'd like a simple and efficient formula/algorithm that finds that at index 3 they intersect. I know I could do a search just wondering if there is a better way. I know there is a formula to solve two lines in y = mx + b form by subtracting them from each other but my "line" isn't truly a line because its limited to the items in the list and it may have curves. Any help is appreciated.

Read the article

taking intersection of N-many lists in python

- by user248237

what's the easiest way to take the intersection of N-many lists in python? if I have two lists a and b, I know I can do: a = set(a) b = set(b) intersect = a.intersection(b) but I want to do something like a & b & c & d & ... for an arbitrary set of lists (ideally without converting to a set first, but if that's the easiest / most efficient way, I can deal with that.) I.e. I want to write a function intersect(*args) that will do it for arbitrarily many sets efficiently. What's the easiest way to do that? EDIT: My own solution is reduce(set.intersection, [a,b,c]) -- is that good? thanks.

Read the article

All Permutations of a string when corresponding characters are not in the same place

- by r20rock

I need all possible permutations of a given string such that no character should remain at the same place as in the input string. Eg. : for input "ask" Output: all possible permutaions like "ksa", "kas"... such that 'a' is not in the 1st position , 's' is not in the 2nd positions and so on... in any permutation. I only need the count of such possible permutations I can do this by generating all permutations and filtering them but I need a very efficient way of doing this. All characters in the string are "UNIQUE" Preferred language C++.

Read the article

php - comparing timestamp dates to make sure user is of minimum age

- by Micheal Ken

When a user signs up the system has to check that they are old enough to do so, in this example they have to be atleast 8 years old $minAge = strtotime(date("d")."-".date("m")."-".(date("Y")-8)); $dob = strtotime($day."-".$month."-".$year); $minAge = 01-03-2004, $dob = 01-02-2011 I basically need to make sure this person was born before 2004 but I want to know whether I have to convert the timestamps to do a comparison or whether there is a more efficient way. Any help is appreciated, thank you

Read the article

C#: Efficiently search a large string for occurences of other strings

- by Jon

Hi, I'm using C# to continuously search for multiple string "keywords" within large strings, which are = 4kb. This code is constantly looping, and sleeps aren't cutting down CPU usage enough while maintaining a reasonable speed. The bog-down is the keyword matching method. I've found a few possibilities, and all of them give similar efficiency. 1) http://tomasp.net/articles/ahocorasick.aspx -I do not have enough keywords for this to be the most efficient algorithm. 2) Regex. Using an instance level, compiled regex. -Provides more functionality than I require, and not quite enough efficiency. 3) String.IndexOf. -I would need to do a "smart" version of this for it provide enough efficiency. Looping through each keyword and calling IndexOf doesn't cut it. Does anyone know of any algorithms or methods that I can use to attain my goal?

Read the article

Add C pointer to NSMutableArray

- by Georges Oates Larsen

I am writing an Objective-C program that deals with low level image memory. I am using ANSI-C structs for my data storage -- Full blown objects seem overkill seeing as the data I am storing is 100% data, with no methods to operate on that data. Specifically, I am writing a customizable posterization algorithm which relies on an array of colors -- This is where things get tricky. I am storing my colors as structs of three floats, and an integer flag (related to the posterization algorithm specifically). Everyhting is going well, except for one thing... [actual question] I can't figure out how to add pointers to an NSMutableArray! I know how to add an object, but adding a pointer to a struct seems to be more difficult -- I do not want NSMutableArray dereferencing my pointer and treating the struct as some sort of strange object. I want NSMutableArray to add the pointer its self to its collection. How do I go about doing this? Thanks in advance, G

Search Results

Search found 9017 results on 361 pages for 'efficient storage'.

Page 254/361 | < Previous Page | 250 251 252 253 254 255 256 257 258 259 260 261 | Next Page >

- by RGrey

- by Andreas

- by Jiho Han

- by GTDev

- by Scott

- by Doug

- by Hans

- by zeroed

- by Brian

- by takeshin

- by Robert Wagner

- by bndz

- by h2g2java

- by Pregzt

- by Itsik

- by ryyst

- by Cj Anderson

- by Stacey

- by D Roddis

- by Xavier

- by user248237

- by r20rock

- by Micheal Ken

- by Jon

- by Georges Oates Larsen

< Previous Page | 250 251 252 253 254 255 256 257 258 259 260 261 | Next Page >