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  • jquery calculation sum two different type of item

    - by st4n
    I'm writing a script like the example shown in the demo where All of the "Total" values (Including the "Grand Total") are Automatically Calculated using the calc () method. at this link: But I have some fields in which to apply the equation qty * price, and others where I want to do other operations .. you can tell me how? thank you very much i try with this, but it is a very stupid code .. and the grandTotal .. not sum the two different fields: function recalc() { $("[id^=total_item]").calc("qty * price", { qty: $("input[name^=qty_item_]"), price: $("[id^=price_item_]") }, function (s){ // return the number as a dollar amount return "$" + s.toFixed(2); }, function ($this){ // sum the total of the $("[id^=total_item]") selector var sum = $this.sum(); $("#grandTotal").text( // round the results to 2 digits "$" + sum.toFixed(2) ); }); $("[id^=total_otheritem]").calc("qty1 / price1", { qty1: $("input[name^=qty_other_]"), price1: $("[id^=price_other_]") }, function (s){ // return the number as a dollar amount return "$" + s.toFixed(2); }, function ($this){ var sum = $this.sum(); $("#grandTotal").text( // round the results to 2 digits "$" + sum.toFixed(2) ); }); }

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  • Use properties or methods to expose business rules in C#?

    - by Val
    I'm writing a class to encapsulate some business rules, each of which is represented by a boolean value. The class will be used in processing an InfoPath form, so the rules get the current program state by looking up values in a global XML data structure using XPath operations. What's the best (most idiomatic) way to expose these rules to callers -- properties or public methods? Call using properties Rules rules = new Rules(); if ( rules.ProjectRequiresApproval ) { // get approval } else { // skip approval } Call using methods Rules rules = new Rules(); if ( rules.ProjectRequiresApproval() ) { // get approval } else { // skip approval } Rules class exposing rules as properties public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule property public bool ProjectRequiresApproval { get { return _amount < threshold } } } Rules class exposing rules as methods public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule method public bool ProjectRequiresApproval() { return _amount < threshold; } } What are the pros and cons of one over the other?

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  • Java - Removing duplicates in an ArrayList

    - by Will
    I'm working on a program that uses an ArrayList to store Strings. The program prompts the user with a menu and allows the user to choose an operation to perform. Such operations are adding Strings to the List, printing the entries etc. What I want to be able to do is create a method called removeDuplicates().This method will search the ArrayList and remove any duplicated values. I want to leave one instance of the duplicated value(s) within the list. I also want this method to return the total number of duplicates removed. I've been trying to use nested loops to accomplish this but I've been running into trouble because when entries get deleted, the indexing of the ArrayList gets altered and things don't work as they should. I know conceptually what I need to do but I'm having trouble implementing this idea in code. Here is some pseudo code: start with first entry; check each subsequent entry in the list and see if it matches the first entry; remove each subsequent entry in the list that matches the first entry; after all entries have been examined, move on to the second entry; check each entry in the list and see if it matches the second entry; remove each entry in the list that matches the second entry; repeat for entry in the list Here's the code I have so far: public int removeDuplicates() { int duplicates = 0; for ( int i = 0; i < strings.size(); i++ ) { for ( int j = 0; j < strings.size(); j++ ) { if ( i == j ) { // i & j refer to same entry so do nothing } else if ( strings.get( j ).equals( strings.get( i ) ) ) { strings.remove( j ); duplicates++; } } } return duplicates; }

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  • re.sub emptying list

    - by jmau5
    def process_dialect_translation_rules(): # Read in lines from the text file specified in sys.argv[1], stripping away # excess whitespace and discarding comments (lines that start with '##'). f_lines = [line.strip() for line in open(sys.argv[1], 'r').readlines()] f_lines = filter(lambda line: not re.match(r'##', line), f_lines) # Remove any occurances of the pattern '\s*<=>\s*'. This leaves us with a # list of lists. Each 2nd level list has two elements: the value to be # translated from and the value to be translated to. Use the sub function # from the re module to get rid of those pesky asterisks. f_lines = [re.split(r'\s*<=>\s*', line) for line in f_lines] f_lines = [re.sub(r'"', '', elem) for elem in line for line in f_lines] This function should take the lines from a file and perform some operations on the lines, such as removing any lines that begin with ##. Another operation that I wish to perform is to remove the quotation marks around the words in the line. However, when the final line of this script runs, f_lines becomes an empty lines. What happened? Requested lines of original file: ## English-Geek Reversible Translation File #1 ## (Moderate Geek) ## Created by Todd WAreham, October 2009 "TV show" <=> "STAR TREK" "food" <=> "pizza" "drink" <=> "Red Bull" "computer" <=> "TRS 80" "girlfriend" <=> "significant other"

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  • MS Excel automation without macros in the generated reports. Any thoughts?

    - by ezeki77
    Hello! I know that the web is full of questions like this one, but I still haven't been able to apply the answers I can find to my situation. I realize there is VBA, but I always disliked having the program/macro living inside the Excel file, with the resulting bloat, security warnings, etc. I'm thinking along the lines of a VBScript that works on a set of Excel files while leaving them macro-free. Now, I've been able to "paint the first column blue" for all files in a directory following this approach, but I need to do more complex operations (charts, pivot tables, etc.), which would be much harder (impossible?) with VBScript than with VBA. For this specific example knowing how to remove all macros from all files after processing would be enough, but all suggestions are welcome. Any good references? Any advice on how to best approach external batch processing of Excel files will be appreciated. Thanks! PS: I eagerly tried Mark Hammond's great PyWin32 package, but the lack of documentation and interpreter feedback discouraged me.

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  • Model class for NSDictionary information with Lazy Loading

    - by samfu_1
    My application utilizes approx. 50+ .plists that are used as NSDictionaries. Several of my view controllers need access to the properties of the dictionaries, so instead of writing duplicate code to retrieve the .plist, convert the values to a dictionary, etc, each time I need the info, I thought a model class to hold the data and supply information would be appropriate. The application isn't very large, but it does handle a good deal of data. I'm not as skilled in writing model classes that conform to the MVC paradigm, and I'm looking for some strategies for this implementation that also supports lazy loading.. This model class should serve to supply data to any view controller that needs it and perform operations on the data (such as adding entries to dictionaries) when requested by the controller functions currently planned: returning the count on any dictionary adding one or more dictionaries together Currently, I have this method for supporting the count lookup for any dictionary. Would this be an example of lazy loading? -(NSInteger)countForDictionary: (NSString *)nameOfDictionary { NSBundle *bundle = [NSBundle mainBundle]; NSString *plistPath = [bundle pathForResource: nameOfDictionary ofType: @"plist"]; //load plist into dictionary NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] initWithContentsOfFile: plistPath]; NSInteger count = [dictionary count] [dictionary release]; [return count] }

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  • Creating a new object destroys an older object with different name in C++

    - by Mikael
    First question here! So, I am having some problems with pointers in Visual C++ 2008. I'm writing a program which will control six cameras and do some processing on them so to clean things up I have created a Camera Manager class. This class handles all operations which will be carried out on all the cameras. Below this is a Camera class which interacts with each individual camera driver and does some basic image processing. Now, the idea is that when the manager is initialised it creates two cameras and adds them to a vector so that I can access them later. The catch here is that when I create the second camera (camera2) the first camera's destructor is called for some reason, which then disconnects the camera. Normally I'd assume that the problem is somewhere in the Camera class, but in this case everything works perfectly as long as I don't create the camera2 object. What's gone wrong? CameraManager.h: #include "stdafx.h" #include <vector> #include "Camera.h" class CameraManager{ std::vector<Camera> cameras; public: CameraManager(); ~CameraManager(); void CaptureAll(); void ShowAll(); }; CameraManager.cpp: #include "stdafx.h" #include "CameraManager.h" CameraManager::CameraManager() { printf("Camera Manager: Initializing\n"); [...] Camera *camera1 = new Camera(NodeInfo,1, -44,0,0); cameras.push_back(*camera1); // Adding the following two lines causes camera1's destructor to be called. Why? Camera *camera2 = new Camera(NodeInfo,0, 44,0,0); cameras.push_back(*camera2); printf("Camera Manager: Ready\n"); }

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  • Recursive Iterators

    - by soandos
    I am having some trouble making an iterator that can traverse the following type of data structure. I have a class called Expression, which has one data member, a List<object>. This list can have any number of children, and some of those children might be other Expression objects. I want to traverse this structure, and print out every non-list object (but I do want to print out the elements of the list of course), but before entering a list, I want to return "begin nest" and after I just exited a list, I want to return "end nest". I was able to do this if I ignored the class wherever possible, and just had List<object> objects with List<object> items if I wanted a subExpression, but I would rather do away with this, and instead have an Expressions as the sublists (it would make it easier to do operations on the object. I am aware that I could use extension methods on the List<object> but it would not be appropriate (who wants an Evaluate method on their list that takes no arguments?). The code that I used to generate the origonal iterator (that works) is: public IEnumerator GetEnumerator(){ return theIterator(expr).GetEnumerator(); } private IEnumerable theIterator(object root) { if ((root is List<object>)){ yield return " begin nest "; foreach (var item in (List<object>)root){ foreach (var item2 in theIterator(item)){ yield return item2; } } yield return " end nest "; } else yield return root; } A type swap of List<object> for expression did not work, and lead to a stackOverflow error. How should the iterator be implemented? Update: Here is the swapped code: public IEnumerator GetEnumerator() { return this.GetEnumerator(); } private IEnumerable theIterator(object root) { if ((root is Expression)) { yield return " begin nest "; foreach (var item in (Expression)root) { foreach (var item2 in theIterator(item)) yield return item2; } yield return " end nest "; } else yield return root; }

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  • Why does GLSL's arithmetic functions yield so different results on the iPad than on the simulator?

    - by cheeesus
    I'm currently chasing some bugs in my OpenGL ES 2.0 fragment shader code which is running on iOS devices. The code runs fine in the simulator, but on the iPad it has huge problems and some of the calculations yield vastly different results, I had for example 0.0 on the iPad and 4013.17 on the simulator, so I'm not talking about small differences which could be the result of some rounding errors. One of the things I noticed is that, on the iPad, float1 = pow(float2, 2.0); can yield results which are very different from the results of float1 = float2 * float2; Specifically, when using pow(x, 2.0) on a variable containing a larger negative number like -8, it seemed to return a value which satified the condition if (powResult <= 0.0). Also, the result of both operations (pow(x, 2.0) as well as x*x) yields different results in the simulator than on the iPad. Used floats are mediump, but I get the same stuff with highp. Is there a simple explanation for those differences? I'm narrowing the problem down, but it takes so much time, so maybe someone can help me here with a simple explanation.

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  • Lightweight HTTP application/server for static content

    - by PartlyCloudy
    Hi, I am in need of a scalable and performant HTTP application/server that will be used for static file serving/uploading. So I only need support for GET and PUT operations. However, there are a few extra features that I need: Custom authentication: I need to check credentials against a database for each request. Thus I must be able to integrate propietary database interaction. Support for signed access keys: The access to resources via PUT should be signed using a key like http://uri/?key=foo The key then contains information about the request like md5(user + path + secret) which allows me to block unwanted requests. The application/server should allow me to check for this. Performance: I'd like to avoid piping content as much as possible. Otherwise the whole application could be implemented in Perl/etc. in a few lines as CGI. Perlbal (in webserver mode) looks nice, however the single-threaded model does not fit with my database lookup and it does also not support query strings. Lighttp/Nginx/… have some modules for these tasks, however it is not feasible putting everything together without ending up writing own extensions/modules. So how would you solve this? Are there other leightweight webservers available for this? Should I implement an application inside of a webserver (i.e. CGI). How can I avoid/speed up piping content between the webserver and my application. Thanks in advance!

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  • What are CAD apps written in, and how are they organized ?

    - by ldigas
    What are CAD applications (Rhino, Autocad) of today written in and how are they organized internally ? I gave as an example, Autocad and Rhino, although I would love to hear of other examples as well. I'm particularly interested in knowing what is their backend written in (multilanguage ?) and how is it organized, and how do they handle their frontend (GUI) in real time ? Do they use native windows API's or some libraries of their own, since I imagine, as good as may be, the open source solutions on today's market won't cut it. I may be wrong ... As most of you who have used them know, they handle amongs other things relatively complex rotational operations in realtime (shading is not interesting me). I've been doing some experiments with several packages recently, and for some larger models found that there is considerable difference in speed in, for example, programed rotation (big full ship models) amongst some of them (which I won't name). So I'm wondering about their internals ... Also, if someone knows of some book on the subject, I'd be interested to hear of it.

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  • manyToOne is creating new products

    - by user788721
    I am trying to implement Sylius Cart Bundle, but every time I add a product to the cart, a new product is created. This is probably link to my line: cascade: ["persist", "remove"] In my YAML File: Pharmacie\FrontBundle\Entity\CartItem: type: entity table: app_cart_item manyToOne: produit: targetEntity: Pharmacie\FrontBundle\Entity\Product cascade: ["persist", "remove"] joinColumn: name: product_id referencedColumnName: id But if take it off, I get an error: A new entity was found through the relationship 'Pharmacie\FrontBundle\Entity\CartItem#produit' that was not configured to cascade persist operations for entity: 3test2. To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity or configure cascade persist this association in the mapping for example @ManyToOne(..,cascade={"persist"}) According to the doctrine doc, this error occurs when you set a new object. But I am only getting an existing object By ID: $product = $this->getProductRepository()->find($productId); $item->setProduit($product); //this generates the error $item->setUnitPrice(5); //this works fine I don't understand why it's save as a new object. If I use merge instead of persist, I get the same error: A new entity was found through the relationship...

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  • Fastest way to perform subset test operation on a large collection of sets with same domain

    - by niktech
    Assume we have trillions of sets stored somewhere. The domain for each of these sets is the same. It is also finite and discrete. So each set may be stored as a bit field (eg: 0000100111...) of a relatively short length (eg: 1024). That is, bit X in the bitfield indicates whether item X (of 1024 possible items) is included in the given set or not. Now, I want to devise a storage structure and an algorithm to efficiently answer the query: what sets in the data store have set Y as a subset. Set Y itself is not present in the data store and is specified at run time. Now the simplest way to solve this would be to AND the bitfield for set Y with bit fields of every set in the data store one by one, picking the ones whose AND result matches Y's bitfield. How can I speed this up? Is there a tree structure (index) or some smart algorithm that would allow me to perform this query without having to AND every stored set's bitfield? Are there databases that already support such operations on large collections of sets?

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  • How to do an additional search on archive in rails if record not found, by extending model?

    - by Nick Gorbikoff
    Hello, I was wondering if somebody knows an elegant solution to the following: Suppose I have a table that holds orders, with a bunch of data. So I'm at 1M records, and searches begin to take time. So I want to speed it up by archiving some data that is more than 3 years old - saving it into a table called orders-archive, and then purging them from the orders table. So if we need to research something or customer wants to pull older information - they still can, but 99% of the lookups are done on the orders no older than a year and a half - so there is no reason to keep looking through older data all the time. These move & purge operations can be then croned to be done on a weekly basis. I already did some tests and I know that I will slash my search times by about 4 times. So far so good, right? However I was thinking about how to implement older archival lookups and the only reasonable thing I can think of is some sort of if-else If not found in orders, do a search in orders-archive. However - I have about 20 tables that I want to archive and god knows how many searches / finds are done through out the code, that I don't want to modify. So I was wondering if there is an elegant rails-way solution to this problem, by extending a model somehow? Has anyone dealt with similar case before? Thank you.

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  • Is there any function in Matlab for changing the form of matrix?

    - by niko
    Hi, I have to get the unknown matrix by changing the form of known matrix considering the following rules: H = [-P'|I] G = [I|P] where H is known matrix G is unknown matrix which has to be calculated I is identity matrix So for example if we had a matrix H = [1 1 1 1 0 0; 0 0 1 1 0 1; 1 0 0 1 1 0] its form has to be changed to H = [1 1 1 1 0 0; 0 1 1 0 1 0; 1 1 0 0 0 1] so -P' = [1 1 1; 0 1 0; 1 1 0] and in case of binary matrices -P = P therefore G = [1 0 0 1 1 1; 0 1 0 0 1 0; 0 0 1 1 1 0] I know how to solve it on the paper by performing basic row operations but don't know how if there is any function already written in Matlab to calculate G from H or H from G by considering the above rules. I would be very thankful if anyone of you could suggest any method for solving the given problem. Thank you.

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  • Analyzing an IronPython Scope

    - by Vercinegetorix
    I'm trying to write C# code with an embedded IronPython script. Then want to analyze the contents of the script, i.e. list all variables, functions, class and their members/methods. There's an easy way to start, assuming I've got a scope defined and code executed in it already: dynamic variables=pyScope.GetVariables(); foreach (string v in variables) { dynamic dynamicV=pyScope.GetVariable(); /*seems to return everything. variables, functions, classes, instances of classes*/ } But how do I figure out what the type of a variable is? For the following python 'objects', dynamicV.GetType() will return different values: x=5 --system.Int32 y="asdf" --system.String def func():... --IronPython.Runtime.PythonFunction z=class() -- IronPython.Runtime.Types.OldInstance, how can I identify what the actual python class is? class NewClass -- throws an error, GetType() is unavailable. This is almost what I'm looking for. I could capture the exception thrown when unavailable and assume it's a class declaration, but that seems unclean. Is there a better approach? To discover the members/methods of a class it looks like I can use: ObjectOperations op = pyEngine.Operations; object instance = op.Call("className"); foreach (string j in op.GetMemberNames("className")) { object member=op.GetMember(instance, j); Console.WriteLine(member.GetType()); /*once again, GetType() provides some info about the type of the member, but returns null sometimes*/ } Also, how do I get the parameters to a method? Thanks!

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  • recvfrom returns invalid argument when *from* is passed

    - by Aditya Sehgal
    I am currently writing a small UDP server program in linux. The UDP server will receive packets from two different peers and will perform different operations based on from which peer it received the packet. I am trying to determine the source from where I receive the packet. However, when select returns and recvfrom is called, it returns with an error of Invalid Argument. If I pass NULL as the second last arguments, recvfrom succeeds. I have tried declaring fromAddr as struct sockaddr_storage, struct sockaddr_in, struct sockaddr without any success. Is their something wrong with this code? Is this the correct way to determine the source of the packet? The code snippet follows. ` /*TODO : update for TCP. use recv */ if((pkInfo->rcvLen=recvfrom(psInfo->sockFd, pkInfo->buffer, MAX_PKTSZ, 0, /* (struct sockaddr*)&fromAddr,*/ NULL, &(addrLen) )) < 0) { perror("RecvFrom failed\n"); } else { /*Apply Filter */ #if 0 struct sockaddr_in* tmpAddr; tmpAddr = (struct sockaddr_in* )&fromAddr; printf("Received Msg From %s\n",inet_ntoa(tmpAddr->sin_addr)); #endif printf("Packet Received of len = %d\n",pkInfo->rcvLen); } `

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  • Can i change the identity of the logged in user in ASP.net?

    - by Rising Star
    I have an ASP.net application I'm developing authentication for. I am using an existing cookie-based log on system to log users in to the system. The application runs as an anonymous account and then checks the cookie when the user wants to do something restricted. This is working fine. However, there is one caveat: I've been told that for each page that connects to our SQL server, I need to make it so that the user connects using an Active Directory account. because the system I'm using is cookie based, the user isn't logged in to Active Directory. Therefore, I use impersonation to connect to the server as a specific account. However, the powers that be here don't like impersonation; they say that it clutters up the code. I agree, but I've found no way around this. It seems that the only way that a user can be logged in to an ASP.net application is by either connecting with Internet Explorer from a machine where the user is logged in with their Active Directory account or by typing an Active Directory username and password. Neither of these two are workable in my application. I think it would be nice if I could make it so that when a user logs in and receives the cookie (which actually comes from a separate log on application, by the way), there could be some code run which tells the application to perform all network operations as the user's Active Directory account, just as if they had typed an Active Directory username and password. It seems like this ought to be possible somehow, but the solution evades me. How can I make this work?

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  • Asp.net mvc inheritance controllers

    - by Ris90
    Hi, I'm studing asp.net mvc and in my test project I have some problems with inheritance: In my model I use inheritanse in few entities: public class Employee:Entity { /* few public properties */ } It is the base class. And descendants: public class RecruitmentOfficeEmployee: Employee { public virtual RecruitmentOffice AssignedOnRecruitmentOffice { get; set; } } public class ResearchInstituteEmployee: Employee { public virtual ResearchInstitute AssignedOnResearchInstitute { get; set; } } I want to implement a simple CRUD operations to every descedant. What is the better way to inplement controllers and views in descendants: - One controller per every descendant; - Controller inheritance; - Generic controller; - Generic methods in one controller. Or maybe there is an another way? My ORM is NHibernate, I have a generic base repository and every repository is its descedant. Using generic controller, I think, is the best way, but in it I will use only generic base repository and extensibility of the system will be not very good. Please, help the newbie)

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  • Java/Hibernate using interfaces over the entities.

    - by Dennetik
    I am using annoted Hibernate, and I'm wondering whether the following is possible. I have to set up a series of interfaces representing the objects that can be persisted, and an interface for the main database class containing several operations for persisting these objects (... an API for the database). Below that, I have to implement these interfaces, and persist them with Hibernate. So I'll have, for example: public interface Data { public String getSomeString(); public void setSomeString(String someString); } @Entity public class HbnData implements Data, Serializable { @Column(name = "some_string") private String someString; public String getSomeString() { return this.someString; } public void setSomeString(String someString) { this.someString = someString; } } Now, this works fine, sort of. The trouble comes when I want nested entities. The interface of what I'd want is easy enough: public interface HasData { public Data getSomeData(); public void setSomeData(Data someData); } But when I implement the class, I can follow the interface, as below, and get an error from Hibernate saying it doesn't know the class "Data". @Entity public class HbnHasData implements HasData, Serializable { @OneToOne(cascade = CascadeType.ALL) private Data someData; public Data getSomeData() { return this.someData; } public void setSomeData(Data someData) { this.someData = someData; } } The simple change would be to change the type from "Data" to "HbnData", but that would obviously break the interface implementation, and thus make the abstraction impossible. Can anyone explain to me how to implement this in a way that it will work with Hibernate?

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  • Java string to double conversion.

    - by wretrOvian
    Hi, I've been reading up on the net about the issues with handling float and double types in java. Unfortunately, the image is still not clear. Hence, i'm asking here direct. :( My MySQL table has various DECIMAL(m,d) columns. The m may range from 5 to 30. d stays a constant at 2. Question 1. What equivalent data-type should i be using in Java to work (i.e store, retrieve, and process) with the size of the values in my table? (I've settled with double - hence this post). Question 2. While trying to parse a double from a string, i'm getting errors Double dpu = new Double(dpuField.getText()); for example - "1" -> java.lang.NumberFormatException: empty String "10" -> 1.0 "101" -> 10.0 "101." -> 101.0 "101.1" -> 101.0 "101.19" -> 101.1 What am i doing wrong? What is the correct way to convert a string to a double value? And what measures should i take to perform operations on such values?

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  • How much is too much memory allocation in NDK?

    - by Maximus
    The NDK download page notes that, "Typical good candidates for the NDK are self-contained, CPU-intensive operations that don't allocate much memory, such as signal processing, physics simulation, and so on." I came from a C background and was excited to try to use the NDK to operate most of my OpenGL ES functions and any native functions related to physics, animation of vertices, etc... I'm finding that I'm relying quite a bit on Native code and wondering if I may be making some mistakes. I've had no trouble with testing at this point, but I'm curious if I may run into problems in the future. For example, I have game struct defined (somewhat like is seen in the San-Angeles example). I'm loading vertex information for objects dynamically (just what is needed for an active game area) so there's quite a bit of memory allocation happening for vertices, normals, texture coordinates, indices and texture graphic data... just to name the essentials. I'm quite careful about freeing what is allocated between game areas. Would I be safer setting some caps on array sizes or should I charge bravely forward as I'm going now?

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  • What OpenGL functions are not GPU accelerated?

    - by Xavier Ho
    I was shocked when I read this (from the OpenGL wiki): glTranslate, glRotate, glScale Are these hardware accelerated? No, there are no known GPUs that execute this. The driver computes the matrix on the CPU and uploads it to the GPU. All the other matrix operations are done on the CPU as well : glPushMatrix, glPopMatrix, glLoadIdentity, glFrustum, glOrtho. This is the reason why these functions are considered deprecated in GL 3.0. You should have your own math library, build your own matrix, upload your matrix to the shader. For a very, very long time I thought most of the OpenGL functions use the GPU to do computation. I'm not sure if this is a common misconception, but after a while of thinking, this makes sense. Old OpenGL functions (2.x and older) are really not suitable for real-world applications, due to too many state switches. This makes me realise that, possibly, many OpenGL functions do not use the GPU at all. So, the question is: Which OpenGL function calls don't use the GPU? I believe knowing the answer to the above question would help me become a better programmer with OpenGL. Please do share some of your insights.

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  • Is locking on the requested object a bad idea?

    - by Quick Joe Smith
    Most advice on thread safety involves some variation of the following pattern: public class Thing { private static readonly object padlock = new object(); private string stuff, andNonsense; public string Stuff { get { lock (Thing.padlock) { if (this.stuff == null) this.stuff = "Threadsafe!"; } return this.stuff; } } public string AndNonsense { get { lock (Thing.padlock) { if (this.andNonsense == null) this.andNonsense = "Also threadsafe!"; } return this.andNonsense; } } // Rest of class... } In cases where the get operations are expensive and unrelated, a single locking object is unsuitable because a call to Stuff would block all calls to AndNonsense, degrading performance. And rather than create a lock object for each call, wouldn't it be better to acquire the lock on the member itself (assuming it is not something that implements SyncRoot or somesuch for that purpose? For example: public string Stuff { get { lock (this.stuff) { // Pretend that this is a very expensive operation. if (this.stuff == null) this.stuff = "Still threadsafe and good?"; } return this.stuff; } } Strangely, I have never seen this approach recommended or warned against. Am I missing something obvious?

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  • Function Returning Negative Value

    - by Geowil
    I still have not run it through enough tests however for some reason, using certain non-negative values, this function will sometimes pass back a negative value. I have done a lot of manual testing in calculator with different values but I have yet to have it display this same behavior. I was wondering if someone would take a look at see if I am missing something. float calcPop(int popRand1, int popRand2, int popRand3, float pERand, float pSRand) { return ((((((23000 * popRand1) * popRand2) * pERand) * pSRand) * popRand3) / 8); } The variables are all contain randomly generated values: popRand1: between 1 and 30 popRand2: between 10 and 30 popRand3: between 50 and 100 pSRand: between 1 and 1000 pERand: between 1.0f and 5500.0f which is then multiplied by 0.001f before being passed to the function above Edit: Alright so after following the execution a bit more closely it is not the fault of this function directly. It produces an infinitely positive float which then flips negative when I use this code later on: pPMax = (int)pPStore; pPStore is a float that holds popCalc's return. So the question now is, how do I stop the formula from doing this? Testing even with very high values in Calculator has never displayed this behavior. Is there something in how the compiler processes the order of operations that is causing this or are my values simply just going too high? If the later I could just increase the division to 16 I think.

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