I found files to change with this command:
git grep 'DO NOT EDIT' | grep -v 'Code generated .* DO NOT'
There are more files that match that grep, but I do not intend on fixing
them.
Change-Id: I4b474f1c29ca3135560d414785b0dbe0d1a4e52c
GitHub-Last-Rev: 65804b0263
GitHub-Pull-Request: golang/go#24334
Reviewed-on: https://go-review.googlesource.com/99955
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This will let us build the latest sort when bootstrapping the compiler.
The compiler depends on the precise tie-breaks used by sort in
some cases, and it's easier to bring sort along than require checking
every sort call ever added to the compiler.
Change-Id: Idc622f89aedbb40d848708c76650fc28779d0c3c
Reviewed-on: https://go-review.googlesource.com/73951
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This is to let sort.Slice get more prominence since
it's the most common use case.
Fixes#21989
Change-Id: I0b180cc20256f5f09065b722e191c508c872f4f7
Reviewed-on: https://go-review.googlesource.com/65710
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
If Less(a, b) returns true when a is less than b, the correct way to
check if a is greater than b is to use Less(b, a). It is wrong to use
!Less(a, b) because that checks if a is greater than *or equal to* b.
1. The decreasingDistance function in Example_sortKeys makes this
mistake. Fix it.
2. The documentation of multiSorter.Less says it loops along the less
functions until it finds a comparison "that is either Less or
!Less". This is nonsense, because (Less(a, b) or !Less(a, b)) is
always true. Fix the documentation to say that it finds a
comparison "that discriminates between the two items (one is less
than the other)". The implementation already does this correctly.
Change-Id: If52b79f68e4fdb0d1095edf29bdecdf154a61b8d
Reviewed-on: https://go-review.googlesource.com/57752
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
There are some major problems with TestAdversary (based on "A Killer
Adversary for Quicksort"[1] by M. D. McIlroy). See #21581 for details.
Rewrite the test to closely match the version in the paper so it can
be verified as correct by virtue of similarity.
The only major difference between this new version and the version in
the paper is that this version swaps the values directly instead of
permuting an array of indices because we don't need to recover the
original permutation.
This new version also counts the number of calls to Less() and fails
the test if there are too many.
Fixes#21581.
[1]: http://www.cs.dartmouth.edu/~doug/mdmspe.pdf
Change-Id: Ia94b5b6d288b8fa3805a5fa27661cebbc5bad9a7
Reviewed-on: https://go-review.googlesource.com/58330
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Done with grep & interactive search & replace, to double-check
replacements. Not many remained after CL 20022.
Fixes#18572
Change-Id: Idbe90ba3b584f9b9661d2bbd141607daaadfa41a
Reviewed-on: https://go-review.googlesource.com/45270
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
ExampleSliceStable echoes the sort.Slice example, to demonstrate sorting
on two fields together preserving order between sorts.
Change-Id: I8afc20c0203991bfd57260431eda73913c165355
Reviewed-on: https://go-review.googlesource.com/37196
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Use fewer instructions to calculate the average of i and j without
overflowing at the addition.
Even if both i and j are math.MaxInt{32,64}, the sum fits into a
uint{32,64}. Because the sum of i and j is always ≥ 0, the right
shift by one does the same as a division by two. The result of the
shift operation is at most math.MaxInt{32,64} and fits again into
an int{32,64}.
name old time/op new time/op delta
SearchWrappers-4 153ns ± 3% 143ns ± 6% -6.33% (p=0.000 n=90+100)
This calculation is documented in:
https://research.googleblog.com/2006/06/extra-extra-read-all-about-it-nearly.html
Change-Id: I2be7922afc03b3617fce32e59364606c37a83678
Reviewed-on: https://go-review.googlesource.com/36332
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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>
Neven Sajko
Mark Rushakoff
Russ Cox
Agniva De Sarker
Karsten Köhler
Tom Levy
Tony Walker
Brad Fitzpatrick
Ian Lance Taylor
Kenny Grant
David R. Jenni
Suyash
Dominik Honnef
Martin Möhrmann
Jure Ham
Matt Bostock
Sokolov Yura
Caleb Spare
Florin Patan
Josh Bleecher Snyder