I'm trying to generate a sales reports which lists each product + total sales in a given month. Its a little tricky because the prices of products can change throughout the month. For example: Between Jan-01 and Jan-15, my company sells 50 Widgets at a cost of $10 each Between Jan-15 and Jan-31, my company sells 50 more Widgets at a co...
Finding routes for a car is pretty easy: you store a weighted graph of all the roads and you could use Djikstra's algorithm [1]. A bus route is less obvious. With a bus you have to represent things like "wait 10 minutes for the next bus" or "walk one block to another bus stop" and feed those into your pathfinding algorithm. It's not eve...
The following is the usual log function I utilize in alot of my vbscripts which I modify accordingly. I feel it writes too slow. I got 3 questions: Any ideaas on how to optimize this so it writes faster? Would it be faster to store all text in a string first then run the function OutputToLog or would it be faster to execute Output...
We try and embed a what string within binary objects so that we can see the version number for an executable or shared library that has been deployed. Typically we embed standard CVS Id information in this what string. For example, we might embed: const char cvsid[] = "@(#)OUR_TEAM_staging_remap_$Revision: 1.30 $ $Name: $"; within th...
I'm looking for an algorithm that rotates an image by some degrees (input). public Image rotateImage(Image image, int degrees) (Image instances could be replaced with int[] containing each pixel RGB values, My problem is that i need to implement it for a JavaME MIDP 2.0 project so i must use code runnable on JVM prior to version 1.5 C...
I'm currently doing something like this in some code I'm working on right now: public CommandType GetCommandTypeFromCommandString(String command) { if(command.StartsWith(CommandConstants.Acknowledge)) return CommandType.Acknowledge; else if (command.StartsWith(CommandConstants.Status)) return CommandType.Status; els...
I ran gprof on a C++ program that took 16.637s, according to time(), and I got this for the first line of output: % cumulative self self total time seconds seconds calls s/call s/call name 31.07 0.32 0.32 5498021 0.00 0.00 [whatever] Why does it list 31.07% of time if ...
I am wondering what kind of optimization techniques people often use nowadays. I have seen people do caching all the time with dictionary and all. Is the trading space for speed the only way to go? ...
Hi again, I need to perform a query 2.5 million times. This query generates some rows which I need to AVG(column) and then use this AVG to filter the table from all values below average. I then need to INSERT these filtered results into a table. The only way to do such a thing with reasonable efficiency, seems to by creating a TEMPORA...
Hi all, We have a table that maintains account balances by recording transactions in that table. i.e. the most recent row is the account balance. When recording a withdrawal, we would like to ensure that the balance can never go negative. Our proposed solution is something like: INSERT INTO `txns` (`account_id`, `prev_balance`, `tx...
Hi everyone and thanks in advance for helping. I rely heavily on nested Master Pages in my web portal, this causes ASP.NET to generate huge ID tags for controls it creates, for example: "ctl00_ctl00_MainBody_ctl00_lblDescription" for a lblDescription Label i've created. Is there any way to reduce this clutter? Any other techniques(so...
In the final stage of development I started looking at code to try to find some bad practices. I discovered that while accessing a page, I'm querying the DB n times (n is the number of rows of an HTML table) just to get the translation (different languages) for a given record... I immediately thought that was bad and I tried a small opti...
I found this question about which languages optimize tail recursion. What I want to know is why C# doesn't optimize tail recursion, whenever possible? For a concrete case, why isn't this method optimized into a loop (VS2008 32 bit, if that matters)?: private static void Foo(int i) { if (i == 1000000) return; if (i % 100 == 0) ...
I have some queries that are causing timeouts in our live environment. (>30 seconds) If I run profiler and grab the exact SQL being run and run it from Management Studio then they take a long time to run the first time and then drop to a few hundred miliseconds each run after that. This is obviously SQL caching the data and getting it ...
Hi, I don't know much about database optimization, but I'm trying to understand this case. Say I have the following table: cities =========== state_id integer name varchar(32) slug varchar(32) Now, say I want to perform queries like this: SELECT * FROM cities WHERE state_id = 123 AND slug = 'some_city' SELECT * FROM cities WHERE st...
I have a system of (first order) ODEs with fairly expensive to compute derivatives. However, the derivatives can be computed considerably cheaper to within given error bounds, either because the derivatives are computed from a convergent series and bounds can be placed on the maximum contribution from dropped terms, or through use of pr...
I have a function that I use to add vectors, like this: public static Vector AddVector(Vector v1, Vector v2) { return new Vector( v1.X + v2.X, v1.Y + v2.Y, v1.Z + v2.Z); } Not very interesting. However, I overload the '+' operator for vectors and in the overload I call the AddVector function to avoid code duplica...
I have a view that has a background image and a CGPath that gets changed as the user touches the screen. Drawing the image with CGContextDrawImage() and then drawing the path on top is not fast enough and it hinders the touch event performance. What I would like to have is to have a bitmap buffer and only draw the changes in the path to ...
I have a database full of time-sensitive data, so on a daily basis I truncate the table and then import the new data (from a merge of other databases) into the truncated table. Currently I am running OPTIMIZE on the table after I have imported the daily refresh of data. However, looking at the mysql OPTIMIZE syntax page http://dev.mysq...
As a fun side-project for myself to help in learning yet another PHP MVC framework, I've been writing Reversi / Othello as a PHP & Ajax application, mostly straightforward stuff. I decided against using a multidimensional array for a number of reasons and instead have a linear array ( in this case 64 elements long ) and a couple methods...