Hi, One more thing: if you have any advice on my code, datasets, or algorithmic approach, please give me your feedback/comments.
Here is the Marlin MergeSort: http://hg.openjdk.java.net/jdk/jdk/file/190b77982361/src/java.desktop/share/classes/sun/java2d/marlin/MergeSort.java Laurent Le ven. 9 nov. 2018 à 08:44, Laurent Bourgès <[email protected]> a écrit : > Hi, > > I am currently testing many sort algorithms to improve the Marlin renderer > (AA 2D shape rasterizer), I integrated since OpenJDK9 and am still > improving for OpenJDK12 . > > I created my MergeSort (top down, check for sorted parts, array / buffer > swap to minimize moves, isort on small sub arrays) that sort 2 int[]: > crossing + edge indices. > It is critical as edge crossings are sorted at every scanline, data are > almost sorted/reversed, not really random. > > 3 questions: > - why is this patch dormant ? I checked in openjdk12 repo and your changes > were not integrated. > - I need a sort() method that works with 2 arrays: data + indices (pointer > like). Such sorted indices are useful to use for lookups c[idx[k]] or to > perform other array permutations... > Would you agree adding such new sort(a[], low, high, indices) > - Marlin uses a ThreadLocal context to avoid any allocation. JDK sort() > impl do not accept parameters to give any buffer[] and avoid allocations. > Would you agree adding such optional parameters (like workbase[]) ? > > I will experiment adapting the DualPivotQuickSort in Marlin renderer and > perform array sort race & rendering benchmarks. > > Cheers, > Laurent > > Le ven. 19 janv. 2018 à 14:38, Vladimir Yaroslavskiy <[email protected]> > a écrit : > >> Hi team, >> >> In Sept 2009 Josh Bloch, Jon Bentley and I introduced new sorting >> algorithm, Dual-Pivot Quicksort, for primitives in JDK 7 and later >> I suggested several improvements of Dual-Pivot Quicksort, which >> were integrated into JDK 8. >> >> Now I have more optimized and faster version of Dual-Pivot Quicksort. >> I have been working on it for the last 5 years. Please, find the >> summary of changes below and sources / diff at webrev [1]. >> >> All tests and benchmarking were run on the most recent build of JDK 10, >> jdk-10-ea+39. The new version shows the better performance on different >> inputs and guarantees n*log(n) on any data. >> >> The new implementation of Dual-Pivot Quicksort is 'all-in-one' version: >> it contains one code for both parallel and sequential sorting algorithms. >> >> Suggested version is 10-20% faster on random data, 1.5-4 times faster >> on nearly structured arrays, 1.5-2 times faster on period inputs. >> >> Parallel Dual-Pivot Quicksort is 1.5-3 times faster than current >> algorithm based on merge sort. >> >> Benchmarking on the test suite, suggested by Jon Bentley, shows the >> boost of performance in 1.4 times. This test suite contains several >> types of inputs, such as random data, nearly structured arrays, data >> with period and so on. Also there are several modifications of inputs >> and parameters which are used in data building. We run sorting on all >> combinations to compare two algorithms. >> >> Please let me know if you have any questions / comments. >> >> Summary of changes: >> >> DualPivotQuicksort class >> ------------------------ >> * Pivots are chosen with another step, the 1-st and 5-th candidates >> are taken as pivots instead of 2-nd and 4-th. >> * Splitting into parts is related to the golden ratio >> * Pivot candidates are sorted by combination of 5-element >> network sorting + insertion sort >> * New backwards partitioning is simpler and more efficient >> * Quicksort tuning parameters were updated >> * Merging sort is invoked on each iteration from Quicksort >> * Additional steps for float/double were fully rewritten >> * Heap sort is invoked on the leftmost part >> * Heap sort is used as a guard against quadratic time >> * Parallel sorting is based on Dual-Pivot Quicksort >> instead of merge sort >> >> SortingAlgorithms class >> ----------------------- >> * Merging sort and pair insertion sort were moved from >> DualPivotQuicksort class >> * Pair insertion sort was simplified and optimized >> * New nano insertion sort was introduced for tiny arrays >> * Merging sort was fully rewritten >> * Optimized merging partitioning is used >> * Merging parameters were updated >> * Merging of runs was fully rewritten >> * Fast version of heap sort was introduced >> * Parallel merging sort was also provided >> >> Sorting / ParallelSorting classes >> --------------------------------- >> * New test cases were added >> * Sources of these classes were unified >> >> Arrays class >> ------------ >> * Calls of Dual-Pivot Quicksort were updated >> * Parallel sorting of primitives was switched to parallel >> Dual-Pivot Quicksort >> * Javadoc was modified >> >> ArraysParallelSortHelpers class >> ------------------------------- >> * Old implementation of parallel sorting for primitives was removed >> * Javadoc was updated >> >> Thank you, >> Vladimir >> >> -------------------------------------------------------------------- >> [1] http://cr.openjdk.java.net/~alanb/DualPivotSortUpdate/webrev.01/ >> -------------------------------------------------------------------- >> >
