openmp

I'm wondering if SSE/AVX operations such as addition and multiplication can be an atomic operation? The reason I ask this is that in OpenMP the atomic construct only works on a limited set of operators. It does not work on for example SSE/AVX additions. Let's assume I had a datatype float4 that corresponds to a SSE register and that the addition operator is defined for float4 to do an SSE addition. In OpenMP I could do a reduction over an array with the following code: float4 sum4 = 0.0f; //sets all four values to zero #pragma omp parallel { float4 sum_private = 0.0f; #pragma omp for nowait

I try to get clang 5.0.0 working for Visual Studio 2015, because I need OpenMP 3.0 features. I installed the clang compiler (not the vs2015 version which does not have any openmp support) and use cmake: cmake_minimum_required(VERSION 2.8.10) project(myproject) find_package(OpenMP) if (OPENMP_FOUND) set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}") set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}") endif() include_directories("include") add_library(libFoo STATIC Foo.cpp) install(TARGETS Foo libFoo LIBRARY DESTINATION lib ARCHIVE DESTINATION lib) When I now try to configure a

Consider the following serial function. When I parallelize my code, every thread will call this function from within the parallel region (not shown). I am trying to make this threadsafe and efficient (fast). float get_stored_value__or__calculate_if_does_not_yet_exist( int A ) { static std::map<int, float> my_map; std::map::iterator it_find = my_map.find(A); //many threads do this often. bool found_A = it_find != my_map.end(); if (found_A) { return it_find->second; } else { float result_for_A = calculate_value(A); //should only be done once, really. my_map[A] = result_for_A; return result_for_A

How can I get the abstract syntax tree of a c program in gcc? I'm trying to automatically insert OpenMP pragmas to the input c program. I need to analyze nested for loops for finding dependencies so that I can insert appropriate OpenMP pragmas. So basically what I want to do is traverse and analyze the abstract syntax tree of the input c program. How do I achieve this? You need full dataflow to find 'dependencies'. Then you will need to actually insert the OpenMP calls. What you want is a program transformation system. GCC probably has the dependency information, but it is famously difficult

I have used OpenMP with gcc for writing parallel code. I am now using Visual C++ 2005 and am trying to figure out how to use OpenMP. There is a compiler option in the Properties->C/C++/Language menu but then it complains the library is missing. Is there a 3rd party implementation for OpenMP or am i just configuring Visual C++ incorrectly? After some research I found out that the OpenMP libs and dlls are not included with Visual C++ 2005 or Visual C++ Express Edition 2008. But with a few workarounds you can get it working. First you need to download the lib files from microsoft which can be

I got lots of error messages when trying to use openmp in a c++ code for building my R package on windows 7: c:/rtools/mingw/bin/../lib/gcc/mingw32/4.5.0/libgomp.a(parallel.o):(.text+0x19): undefined reference to `_imp__pthread_getspecific' c:/rtools/mingw/bin/../lib/gcc/mingw32/4.5.0/libgomp.a(parallel.o):(.text+0x7a): undefined reference to `_imp__pthread_mutex_lock' c:/rtools/mingw/bin/../lib/gcc/mingw32/4.5.0/libgomp.a(env.o):(.text+0x510): undefined reference to `_imp__pthread_mutex_init' ... Is Rtools not supporting openmp? Does anyone know how to use openmp in windows R packages please?