| commit | 194ae3236d81cf16dc39b955efc1b9202b59d067 | [log] [tgz] |
|---|---|---|
| author | Rémy Oudompheng <remyoudompheng@gmail.com> | Sun Apr 14 08:16:13 2019 +0200 |
| committer | Robert Griesemer <gri@golang.org> | Tue Nov 12 05:18:25 2019 +0000 |
| tree | 246ff4032a9c72642e78782c018abc18d8a5e749 | |
| parent | b8cb75fb17511538524ac304abe68e62699c4e23 [diff] |
math/big: implement recursive algorithm for division The current division algorithm produces one word of result at a time, using 2-word division to compute the top word and mulAddVWW to compute the remainder. The top word may need to be adjusted by 1 or 2 units. The recursive version, based on Burnikel, Ziegler, "Fast Recursive Division", uses the same principles, but in a multi-word setting, so that multiplication benefits from the Karatsuba algorithm (and possibly later improvements). benchmark old ns/op new ns/op delta BenchmarkDiv/20/10-4 38.2 38.3 +0.26% BenchmarkDiv/40/20-4 38.7 38.5 -0.52% BenchmarkDiv/100/50-4 62.5 62.6 +0.16% BenchmarkDiv/200/100-4 238 259 +8.82% BenchmarkDiv/400/200-4 311 338 +8.68% BenchmarkDiv/1000/500-4 604 649 +7.45% BenchmarkDiv/2000/1000-4 1214 1278 +5.27% BenchmarkDiv/20000/10000-4 38279 36510 -4.62% BenchmarkDiv/200000/100000-4 3022057 1359615 -55.01% BenchmarkDiv/2000000/1000000-4 310827664 54012939 -82.62% BenchmarkDiv/20000000/10000000-4 33272829421 1965401359 -94.09% BenchmarkString/10/Base10-4 158 156 -1.27% BenchmarkString/100/Base10-4 797 792 -0.63% BenchmarkString/1000/Base10-4 3677 3814 +3.73% BenchmarkString/10000/Base10-4 16633 17116 +2.90% BenchmarkString/100000/Base10-4 5779029 1793808 -68.96% BenchmarkString/1000000/Base10-4 889840820 85524031 -90.39% BenchmarkString/10000000/Base10-4 134338236860 4935657026 -96.33% Fixes #21960 Updates #30943 Change-Id: I134c6f81a47870c688ca95b6081eb9211def15a2 Reviewed-on: https://go-review.googlesource.com/c/go/+/172018 Reviewed-by: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
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