The guy who said “leave it to the compiler” was right, but I don’t have the “reputation” to mod him up or comment. I asked gcc to compile int test(int a) { return a / 3; } for an ix86 and then disassembled the output. Just for academic interest, what it’s doing is roughly multiplying … Read more
As I pointed out in How to implement incremental search on a list you should use structures like a Trie or Patricia trie for searching patterns in large texts. And for discovering patterns in the middle of some text there is one simple solution. I am not sure if it is the most efficient solution, … Read more
The majority of the technical information about the architecture and approach of the GHC system is in their wiki. I’ll link to the key pieces, and some related papers that people may not know about. What typical optimizations are applied? The key paper on this is: A transformation-based optimiser for Haskell, SL Peyton Jones and … Read more
Achievement systems are really just a form of logging. For a system like this, publish/subscribe is a good approach. In this case, players publish information about themselves, and interested software components (that handle individual achievements) can subscribe. This allows you to watch public values with specialised logging code, without affecting any core game logic. Take … Read more
The frequency impact depends on the width of the operation and the specific instruction used. There are three frequency levels, so-called licenses, from fastest to slowest: L0, L1 and L2. L0 is the “nominal” speed you’ll see written on the box: when the chip says “3.5 GHz turbo”, they are referring to the single-core L0 … Read more
why don´t you try to use google API for direction, based on basic http requests. https://developers.google.com/maps/documentation/directions/ . (check the conditions on licensing and nº of requests). And then plot the the data with IOS MKPolyline. i´m Sure you will have better performance. And you will only depend on google for the positioning data. to convert … Read more
One of the things you have to realise when dealing with O notation is that it is often very important to understand what n is. If the n is something related to something you can control (eg: the number of elements in a list you want sorted) then it makes sense to look hard at … Read more
http://www.postgresql.org/docs/8.2/static/using-explain.html Basically, a sequential scan is going to the actual rows, and start reading from row 1, and continue until the query is satisfied (this may not be the entire table, e.g., in the case of limit) Bitmap heap scan means that PostgreSQL has found a small subset of rows to fetch (e.g., from an … Read more
I’m using the following tools to perform lossless image compression: pngcrush gifsicle jpegtran For each of the programs, I’ve created two shortcuts: One that does the actual compression, and shows the file size of both files One that replaces the original file with the compressed one (If I’m satisfied, I’ll do arrow-up, prefix my previous … Read more
Usually, the microprocessor does comparison using electrical gates and not step by step like that. It checks all bits at once.