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c++ Programming Glossary: averageWhy is transposing a matrix of 512x512 much slower than transposing a matrix of 513x513? http://stackoverflow.com/questions/11413855/why-is-transposing-a-matrix-of-512x512-much-slower-than-transposing-a-matrix-of the size duh . I posted two versions on ideone size 512 average 2.46 ms http ideone.com 1PV7m size 513 average 0.75 ms http.. size 512 average 2.46 ms http ideone.com 1PV7m size 513 average 0.75 ms http ideone.com NShpo In my environment MSVS 2010 full.. 2010 full optimizations the difference is similar size 512 average 2.19 ms size 513 average 0.57 ms Why is this happening c performance..
Why is my program slow when looping over exactly 8192 elements? http://stackoverflow.com/questions/12264970/why-is-my-program-slow-when-looping-over-exactly-8192-elements make a matrix res and each field in here is made to be the average of the 9 fields around it in the img matrix. The border is left..
Critique my non-intrusive heap debugger http://stackoverflow.com/questions/2835416/critique-my-non-intrusive-heap-debugger tested. It might be interesting to know the total and average number of allocations at any given time The total max min and.. of allocations at any given time The total max min and average bytes allocated and the average lifespan of allocations. If.. time The total max min and average bytes allocated and the average lifespan of allocations. If you want to compare different threads..
What can I use to profile C++ code in Linux? http://stackoverflow.com/questions/375913/what-can-i-use-to-profile-c-code-in-linux way to answer is to say that it's a Beta distribution with average value number of hits 1 number of tries 2 2 1 2 2 75 . The key.. that it sees. And it will see them with a frequency on average proportional to their cost. If n samples are taken and f is..
http://stackoverflow.com/questions/4707012/c-memcpy-vs-stdcopy 3.03 6.10 6.29 3.02 6.08 6.27 3.03 6.08 6.27 3.03 Total average increase in speed of std copy over memcpy 2.99 My compiler is.. 0.54 5.53 5.57 0.72 5.59 5.57 0.36 5.57 5.56 0.18 Total average decrease in speed of std copy over memcpy 0.11 Code for my MD5.. 0.36 5.54 5.58 0.72 5.51 5.58 1.25 5.54 5.57 0.54 Total average increase in speed of std copy over memcpy 0.72 In summary there..
How to solve Memory Fragmentation http://stackoverflow.com/questions/60871/how-to-solve-memory-fragmentation the total number of blocks that it is divided over. If the average free block size is relatively small compared to the total free..
Advice on a better way to extend C++ STL container with user-defined methods http://stackoverflow.com/questions/679520/advice-on-a-better-way-to-extend-c-stl-container-with-user-defined-methods idx this size idx cSum this idx .c return cSum this size average EDIT Thanks for a bunch of thoughtful answers. I will create..
How much footprint does C++ exception handling add http://stackoverflow.com/questions/691168/how-much-footprint-does-c-exception-handling-add I'm interested in your experiences especially What is average footprint added by your compiler for the exception handling.. overhead isn't easily quantifiable but Eckel states an average of 5 and 15 percent. This will depend on the size of your exception..
http://stackoverflow.com/questions/712639/understanding-the-meaning-of-the-term-and-the-concept-raii-resource-acquisiti Relying on that RAII can solve many nasty problems the average programmer might not even be aware of. Here are a few examples..
how to achieve 4 FLOPs per cycle http://stackoverflow.com/questions/8389648/how-to-achieve-4-flops-per-cycle are completely independent from each other and take on average 6 cycles to execute. So there's 12 instructions and 6 cycles..
Advantage of switch over if-else statement http://stackoverflow.com/questions/97987/advantage-of-switch-over-if-else-statement a binary decision tree saves compares and jumps in the average case or simply build a jump table works without compares at..
Why is transposing a matrix of 512x512 much slower than transposing a matrix of 513x513? http://stackoverflow.com/questions/11413855/why-is-transposing-a-matrix-of-512x512-much-slower-than-transposing-a-matrix-of int i 0 i SAMPLES i transpose int elapsed clock t std cout Average for a matrix of MATSIZE elapsed SAMPLES Changing MATSIZE lets..
http://stackoverflow.com/questions/5232198/about-vectors-growth was increased to 2 the first element had to be copied. Average copies per element is 0.5 size 3 capacity 4 When the vector's.. increased to 4 the first two elements had to be copied. Average copies per element is 2 1 0 3 1. size 4 capacity 4 Average copies.. Average copies per element is 2 1 0 3 1. size 4 capacity 4 Average copies per element is 2 1 0 0 4 3 4 0.75. size 5 capacity 8..
How does photoshop blend two images together? http://stackoverflow.com/questions/5919663/how-does-photoshop-blend-two-images-together A B uint8 A B 255 #define ChannelBlend_Average A B uint8 A B 2 #define ChannelBlend_Add A B uint8 min 255 A.. T A B ColorBlend_Buffer T A B Multiply #define ColorBlend_Average T A B ColorBlend_Buffer T A B Average #define ColorBlend_Add.. #define ColorBlend_Average T A B ColorBlend_Buffer T A B Average #define ColorBlend_Add T A B ColorBlend_Buffer T A B Add #define..
Optimizations for pow() with const non-integer exponent? http://stackoverflow.com/questions/6475373/optimizations-for-pow-with-const-non-integer-exponent x^3 x^ 0.4 x^ 0.2 two mulps . This is the underestimate. Average the above one addps one mulps . Instruction tally fourteen including..
Is inline assembly language slower than native C++ code? http://stackoverflow.com/questions/9601427/is-inline-assembly-language-slower-than-native-c-code Debug Release 732 668 733 680 659 672 667 675 684 694 Average 677 Function of C version Debug Release 1068 168 999 166 1072.. Debug Release 1068 168 999 166 1072 231 1002 166 1114 183 Average 182 The C code in release mode is almost 3.7 times faster than..
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