Change-Id: I9783d8023d453a72c4605a308064bef98168bcb8
Reviewed-on: https://go-review.googlesource.com/30360
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This adds examples showing the different ways of using sort.Search.
Change-Id: Iaa08b4501691f37908317fdcf2e618fbe9f99ade
Reviewed-on: https://go-review.googlesource.com/29131
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
No coverage is gained by running the 1e6 versions of the test over the
1e4 versions. It just adds 140 seconds of race overhead time.
Updates #17104
Change-Id: I41408aedae34a8b1a148eebdda20269cdefffba3
Reviewed-on: https://go-review.googlesource.com/29159
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This change removes a lot of dead code. Some of the code has never been
used, not even when it was first commited. The rest shouldn't have
survived refactors.
This change doesn't remove unused routines helpful for debugging, nor
does it remove code that's used in commented out blocks of code that are
only unused temporarily. Furthermore, unused constants weren't removed
when they were part of a set of constants from specifications.
One noteworthy omission from this CL are about 1000 lines of unused code
in cmd/fix, 700 lines of which are the typechecker, which hasn't been
used ever since the pre-Go 1 fixes have been removed. I wasn't sure if
this code should stick around for future uses of cmd/fix or be culled as
well.
Change-Id: Ib714bc7e487edc11ad23ba1c3222d1fd02e4a549
Reviewed-on: https://go-review.googlesource.com/20926
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Fixes#14377
Change-Id: I130a6e1b8bc827db44efd0a74e759b894ecc4977
Reviewed-on: https://go-review.googlesource.com/19823
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Fix `reverences`, which I believe should read as `references`.
Change-Id: I450efcbeee0f8861a84b209f2e6636764034232a
Reviewed-on: https://go-review.googlesource.com/19469
Reviewed-by: Russ Cox <rsc@golang.org>
Revert "Revert "sort: improve average quicksort performance""
This reverts commit 30b87bb9aa.
See https://golang.org/cl/15688 for the CL being replayed.
Change-Id: I2ba36334003f4971f95a10536adfdd86be9a50de
Reviewed-on: https://go-review.googlesource.com/17389
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
- change way of protection from O(N^2) on duplicate values.
Previous algorithm does additional comparisons and swaps
on every split pass.
Changed algorithm does one ordinal quicksort split pass,
and if distribution is skewed, then additional pass to
separate pivot's duplicates.
Changed algorithm could be slower on very ununique slice,
but it is still protected from O(N^2).
- increase small slice size and do simple shell sort pass
to amortize worst case on small slices.
Small slice has higher probability to have skewed
distribution, so lets sort it with simpler algorithm.
benchmark old ns/op new ns/op delta
BenchmarkSortString1K 458374 388641 -15.21%
BenchmarkSortInt1K 217851 181796 -16.55%
BenchmarkSortInt64K 20539264 16730340 -18.54%
BenchmarkSort1e2 98668 95554 -3.16%
BenchmarkSort1e4 20278500 18316829 -9.67%
BenchmarkSort1e6 3215724392 2795999911 -13.05%
number of operations:
Size: Total: Swap: Less:
% % %
Sort 100 Avg -5.98% -18.43% -1.90%
Sort 100 Max -14.43% -16.02% -4.51%
Sort 300 Avg -7.50% -12.76% -5.96%
Sort 300 Max -11.29% -9.60% -4.30%
Sort 1000 Avg -12.13% -11.65% -12.25%
Sort 1000 Max -13.81% -11.77% -11.89%
Sort 3000 Avg -14.61% -9.30% -15.86%
Sort 3000 Max -15.81% -8.66% -15.19%
Sort 10000 Avg -16.10% -8.47% -17.80%
Sort 10000 Max -17.13% -7.63% -16.97%
Sort 30000 Avg -17.46% -7.56% -19.57%
Sort 30000 Max -18.24% -7.62% -17.68%
Sort 100000 Avg -18.83% -6.64% -21.33%
Sort 100000 Max -19.72% -6.70% -20.96%
Sort 300000 Avg -19.61% -6.16% -22.30%
Sort 300000 Max -20.69% -6.15% -21.81%
Sort 1000000 Avg -20.42% -5.58% -23.31%
Sort 1000000 Max -21.54% -5.56% -23.61%
Change-Id: I23868e8b52b5841b358cd5403967c9a97871e4d5
Reviewed-on: https://go-review.googlesource.com/15688
Reviewed-by: Russ Cox <rsc@golang.org>
Correct 'an' to 'on' in the comment above the Stable() function.
Change-Id: I714e38b2d3a79dfd539d5368967d1c6b519cb948
Reviewed-on: https://go-review.googlesource.com/13662
Reviewed-by: Rob Pike <r@golang.org>
There was a small typo in the comment before the Stable function.
Change-Id: Ia6fa5272aa7869124a637d2eeda81c4f35ef46c8
Reviewed-on: https://go-review.googlesource.com/4201
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
For some cases we can ensure the correct order of elements in two
instead of three comparisons. It is unnecessary to compare m0 and
m1 again if m2 and m1 are not swapped.
benchmark old ns/op new ns/op delta
BenchmarkSortString1K 302721 299590 -1.03%
BenchmarkSortInt1K 124055 123215 -0.68%
BenchmarkSortInt64K 12291522 12203402 -0.72%
BenchmarkSort1e2 58027 57111 -1.58%
BenchmarkSort1e4 12426805 12341761 -0.68%
BenchmarkSort1e6 1966250030 1960557883 -0.29%
Change-Id: I2b17ff8dee310ec9ab92a6f569a95932538768a9
Reviewed-on: https://go-review.googlesource.com/2614
Reviewed-by: Robert Griesemer <gri@golang.org>
Use direct binary insertion instead of recursive calls to symMerge
when one of the blocks has only one element.
benchmark old ns/op new ns/op delta
BenchmarkStableString1K 421999 397629 -5.77%
BenchmarkStableInt1K 123422 120592 -2.29%
BenchmarkStableInt64K 9629094 9620200 -0.09%
BenchmarkStable1e2 123089 120209 -2.34%
BenchmarkStable1e4 39505228 36870029 -6.67%
BenchmarkStable1e6 8196612367 7630840157 -6.90%
Change-Id: I49905a909e8595cfa05920ccf9aa00a8f3036110
Reviewed-on: https://go-review.googlesource.com/2219
Reviewed-by: Robert Griesemer <gri@golang.org>
Move the checks for empty rotate changes
from the beginning of rotate to the callers.
Remove additional variable p used instead of existing m with same value.
Remove special casing of equal ranges (i==j) to exit early as no
work is saved vs checking (i!=j) and making a single
swapRange call if this is false.
benchmark old ns/op new ns/op delta
BenchmarkStableString1K 417195 425218 +1.92%
BenchmarkStableInt1K 126661 124498 -1.71%
BenchmarkStableInt64K 10365014 10417438 +0.51%
BenchmarkStable1e2 132151 130648 -1.14%
BenchmarkStable1e4 42027428 40812649 -2.89%
BenchmarkStable1e6 8524772364 8430192391 -1.11%
Change-Id: Ia7642e9d31408496970c700f5843d53cc3ebe817
Reviewed-on: https://go-review.googlesource.com/2100
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Move the symMerge recursion stopping condition
from the beginning of symMerge to the callers.
This halves the number of calls to symMerge
while running 'go test sort'.
benchmark old ns/op new ns/op delta
BenchmarkStable1e6 8358117060 7954143849 -4.83%
BenchmarkStable1e4 40116117 38583285 -3.82%
BenchmarkStableInt1K 119150 115182 -3.33%
BenchmarkStableInt64K 9799845 9515475 -2.90%
BenchmarkStableString1K 388901 393516 +1.19%
BenchmarkStable1e2 124917 123618 -1.04%
Change-Id: I7ba2ca277f213b076fe6830e1139edb47ac53800
Reviewed-on: https://go-review.googlesource.com/1820
Reviewed-by: Robert Griesemer <gri@golang.org>
