c++ Programming Glossary: omp

http://stackoverflow.com/questions/10587598/simd-prefix-sum-on-intel-cpu

each pair in parallel recursively until all sum have been computed like below in parallel do for int i 0 i z.length i z i.. more clear z is not the final ouput but instead used to compute the ouput int w computePrefixSum z for int i 1 i ouput.length.. final ouput but instead used to compute the ouput int w computePrefixSum z for int i 1 i ouput.length i ouput i i 2 0 x..

C++ 2011 : std::thread : simple example to parallelize a loop?

http://stackoverflow.com/questions/10792157/c-2011-stdthread-simple-example-to-parallelize-a-loop

is how do you parallelize a simple for loop like using omp parallel for with std thread I search for an example . Thank.. the disadvantages like the missing load balancing and the complexity for a simple loop. typedef std vector int container typedef..

OpenMP: for schedule

http://stackoverflow.com/questions/10850155/openmp-for-schedule

with OpenMP C and I have some questions 1 What is #pragma omp for schedule 2 What is the difference between dynamic and static.. run something like this char a char malloc 8 4096 #pragma omp parallel for schedule static 1 num_threads 8 for int i 0 i 8.. ... a 32768 Now lets run another loop like this #pragma omp parallel for schedule static 1 num_threads 8 for i 0 i 8 i memset..

How does the omp ordered clause work?

http://stackoverflow.com/questions/13224155/how-does-the-omp-ordered-clause-work

does the omp ordered clause work vector int v #pragma omp parallel for ordered.. does the omp ordered clause work vector int v #pragma omp parallel for ordered schedule dynamic anyChunkSizeGreaterThan1.. for int i 0 i n i ... ... ... #pragma omp order v.push_back i This fills v with an n sized ordered list...

Performance degradation due to default initialisation of elements in standard containers

http://stackoverflow.com/questions/15952412/performance-degradation-due-to-default-initialisation-of-elements-in-standard-co

see below EDIT Sorry the original question didn't use compiler optimization. This is now fixed but to avoid trivial optimization.. to my actual use case the test has been split into two compilation units. The fact that the constructor of std vector has.. The fact that the constructor of std vector has linear complexity is a nuisance when it comes to performance critical applications...

How can I measure CPU time and wall clock time on both Linux/Windows?

http://stackoverflow.com/questions/17432502/how-can-i-measure-cpu-time-and-wall-clock-time-on-both-linux-windows

wall0 get_wall_time double cpu0 get_cpu_time Perform some computation. double sum 0 #pragma omp parallel for reduction sum.. Perform some computation. double sum 0 #pragma omp parallel for reduction sum for long long i 1 i 10000000000 i..

how to achieve 4 FLOPs per cycle

http://stackoverflow.com/questions/8389648/how-to-achieve-4-flops-per-cycle

it take 3 cycles for an sse add and 5 cycles for a mul to complete on most of the modern Intel cpu's see e.g. Agner Fog's 'Instruction.. mul int ops need to initialise differently otherwise compiler might optimise away double sum1 0.1 sum2 0.1 sum3 0.2 sum4.. .3f Gflops res f n t double n t 1e9 x return EXIT_SUCCESS Compiled with g O2 march native addmul.cpp . a.out 1000 produces..