Assume we want to count something in an OpenMP loop. Compare the reductionwith the atomic incrementThe atomic access provides the result immediately, while a reduction only assumes its correct value at the end of the loop. For instance, reductions do not allow this:
After reading the documentation I'm still confused about the usage of par_unseq. I know I can't tell anything about the order of execution because of threading and vectorization but can I still rely on the order of the outputs?
Let's say i have a List<Integer> ints = new ArrayList<>(); and i want to add values to it and compare the results of parallel execution using forEach() and Collectors.toList().