The problem here is not so much with the library as it is with the way the library is linked. Granted, iostream is a moderately huge library but I don’t think it can be so huge as to cause a program to generate an executable that is 900KB larger than a similar one that uses … Read more
There is away to tell compiler to stop checking aliasing: please add line: #pragma GCC ivdep right in front of the loop you want to vectorize, if you need more information please read: https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Loop-Specific-Pragmas.html
“tight as reasonable” -> Something working is better than nothing. These code fragments provide a simple solution to stuff shapes (also triangles) band by band into a rectangle. public abstract class Shape { protected Point offset = new Point(); public abstract int getHeight(); public abstract int getWidth(); } public class Triangle extends Shape { // … Read more
I’ve tested typed arrays, the QSIP version seems to be good in modern browsers: 2 000 000 elements QSIP_TYPED | RDXIP_TYPED | QSIP_STD | RDXIP_STD ———————————————————- Chrome | 300 1000 600 1300 Firefox | 550 1500 800 1600 http://jsfiddle.net/u8t2a/35/ Support (source: http://caniuse.com/typedarrays): IE 10+ | FF 4+ | Chrome 7+ | Safari 5.1+ | Opera … Read more
The simple way is don’t test Object vs Object collisions, populate an array with the center point of each ball. Then, from each center scan a a square of size 4*radius centered on that point (you can optimize this a bit by not using a square, at the expense of making the code more complex). … Read more
If you want a simple answer, it is that there is no simple answer. No amount of calling answers (and by implication people) “lazy” is going to help. How fast should I expect memory allocations to run (MB/s) on a standard modern CPU? At the speed at which the JVM can zero memory, assuming that … Read more
The main method for detecting memory leaks is heap profiling. Specifically, you’re looking for unexpected growth in the amount of resident (mostly heap) memory, either the maximum residency in the +RTS -s statistics output, or — more reliably — a characteristic “pyramid” shape over time in heap profile output generated with the +RTS -h<x> flags … Read more
void memset64( void * dest, uint64_t value, uintptr_t size ) { uintptr_t i; for( i = 0; i < (size & (~7)); i+=8 ) { memcpy( ((char*)dest) + i, &value, 8 ); } for( ; i < size; i++ ) { ((char*)dest)[i] = ((char*)&value)[i&7]; } } (Explanation, as requested in the comments: when you assign … Read more
One important thing most people forget when talking about Big-O, thus I feel the need to mention that: You cannot use Big-O to compare the speed of two algorithms. Big-O only says how much slower an algorithm will get (approximately) if you double the number of items processed, or how much faster it will get … Read more
Assuming every input will be a valid ActivCode, that you can change the enumeration values and highly coupled to the GetHashCode implementation: enum MarketDataExchange { NONE, NBBO = 371857150, AMEX = 372029405, BSE = 372029408, BATS = -1850320644, NSE = 372029407, CHX = -284236702, NYSE = 372029412, ARCA = -734575383, NASDAQ = 372029421, NASDAQ_ADF = … Read more