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K2
,→Assignment2
This is launch statement. we use nested for loop. i is stage and it increases until log2(n). for example, let say n is 16, so i is 1 to 4. Another for loop represents round and round cannot be bigger than stage.
[[File:bitonicKernel.jpgpng]] This is bitonic kernel. There are several variables. '''Gap'''gap expresses gap between 2 elements that will be compared. for example, if stage is 2 and round is 1, gap will be 2. because index 0 will be compared with index 2 and index 1 will be compared with index 3. if stage is 2 and round is 2, gap will be 1 and index 0 will be compared with index 1 so on. '''Group'''group shows where each threads are involved in whether ascending or descending order. for example, thread 0 in stage 1 will be 0 because (0 / ( 1 << (1-1))) % 2 = 0 and thread 1 will be 1 because (1 / (1 << (1-1))) % 2 = 1. so in stage 1, thread will have 0 1 0 1 0 1 .... so each threads will sort in ascending and in descending in order. if stage is 2, thread 0 will be 0 and thread 1 will also be 0 because ( 1 / (1 << 1)) % 2 = 0. so each threads in stage 2 will have 0 0 1 1 0 0 1 1 ....