The root block was used as a sentinel. This means we always need to
allocate a second block on the heap, even if the set has a few small
elements.
We now use the root block: it is always the block with the smallest
offset. The logic becomes very messy if there is no sentinel; to avoid
this we still use a sentinel (a special singleton block) and return it
in when appropriate in the first, last, next wrappers.
Also adding some benchmarks and making some optimizations:
name old time/op new time/op delta
Popcount-4 2.18ns ± 1% 2.21ns ± 1% +1.47%
InsertProbeSparse_2_10-4 76.2ns ±23% 37.2ns ± 1% -51.21%
InsertProbeSparse_10_10-4 240ns ±15% 162ns ± 4% -32.58%
InsertProbeSparse_10_1000-4 419ns ± 4% 371ns ±19% -11.43%
InsertProbeSparse_100_100-4 2.30µs ± 1% 1.93µs ± 1% -16.08%
InsertProbeSparse_100_10000-4 2.12µs ± 3% 2.07µs ± 1% -2.11%
UnionDifferenceSparse-4 165µs ±16% 170µs ± 9% ~
UnionDifferenceHashTable-4 310µs ±10% 291µs ±17% ~
AppendTo-4 11.0µs ± 0% 11.0µs ± 0% -0.35%
name old alloc/op new alloc/op delta
Popcount-4 0.00B ±NaN% 0.00B ±NaN% ~
InsertProbeSparse_2_10-4 64.0B ± 0% 0.0B ±NaN% -100.00%
InsertProbeSparse_10_10-4 64.0B ± 0% 0.0B ±NaN% -100.00%
InsertProbeSparse_10_1000-4 256B ± 0% 192B ± 0% -25.00%
InsertProbeSparse_100_100-4 64.0B ± 0% 0.0B ±NaN% -100.00%
InsertProbeSparse_100_10000-4 256B ± 0% 192B ± 0% -25.00%
UnionDifferenceSparse-4 59.4kB ± 0% 59.2kB ± 0% -0.32%
UnionDifferenceHashTable-4 138kB ± 0% 138kB ± 0% ~
AppendTo-4 0.00B ±NaN% 0.00B ±NaN% ~
name old allocs/op new allocs/op delta
Popcount-4 0.00 ±NaN% 0.00 ±NaN% ~
InsertProbeSparse_2_10-4 1.00 ± 0% 0.00 ±NaN% -100.00%
InsertProbeSparse_10_10-4 1.00 ± 0% 0.00 ±NaN% -100.00%
InsertProbeSparse_10_1000-4 4.00 ± 0% 3.00 ± 0% -25.00%
InsertProbeSparse_100_100-4 1.00 ± 0% 0.00 ±NaN% -100.00%
InsertProbeSparse_100_10000-4 4.00 ± 0% 3.00 ± 0% -25.00%
UnionDifferenceSparse-4 928 ± 0% 925 ± 0% -0.32%
UnionDifferenceHashTable-4 271 ± 0% 271 ± 0% ~
AppendTo-4 0.00 ±NaN% 0.00 ±NaN% ~
Fixesgolang/go#21311.
Change-Id: Ie472a2afa269c21cb33b22ffdac8dd2594b816ac
Reviewed-on: https://go-review.googlesource.com/53431
Reviewed-by: Alan Donovan <adonovan@google.com>
This reverts commit 79902b439b.
Reason for revert: build broken on some platforms.
Change-Id: I5ceddc305580ff97f47ae27da831f99e96dab424
Reviewed-on: https://go-review.googlesource.com/37539
Reviewed-by: David R. Jenni <david.r.jenni@gmail.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Found with honnef.co/go/tools/cmd/unused.
Change-Id: I54dab41d423050b883a3af1f5bb8c5119e2b7100
Reviewed-on: https://go-review.googlesource.com/37602
Reviewed-by: Alan Donovan <adonovan@google.com>
Use the compiler intrinsic __builtin_popcount.
Change-Id: I58286fbcf66d1068390ea9caff2f98b8fe244c2d
Reviewed-on: https://go-review.googlesource.com/16831
Reviewed-by: Andrew Gerrand <adg@golang.org>
Change-Id: I6f3b351d42f5534dd5a5ff161f1e5680b4dbfd58
Reviewed-on: https://go-review.googlesource.com/16793
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
App Engine is amd64 but it doesn't support uploading assembly files.
Use the explicit build tag so that it selects the generic implementation
on App Engine.
This is required to deploy golang.org.
Change-Id: I7374c91961c53d59f6fdcc9ac98b8a9cec755b2c
Reviewed-on: https://go-review.googlesource.com/15246
Reviewed-by: Andrew Gerrand <adg@golang.org>
This function accounts for 2% of "godoc -analysis=pointer"
and this change makes it twice as fast---and simpler.
Added test and benchmark.
Change-Id: I8578fa42dce34df057d81f6c522a7b4e0506d09d
Reviewed-on: https://go-review.googlesource.com/15211
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Just reading through intsets and decided to knock out a few TODOs.
Change-Id: I677dbcc5ff934fbe0f0af09a4741e708a893f8db
Reviewed-on: https://go-review.googlesource.com/2733
Reviewed-by: Alan Donovan <adonovan@google.com>
Fixes various problems reported by go vet.
Change-Id: I12a6fdba8f911b21805d8e42903f8f6a5033790a
Reviewed-on: https://go-review.googlesource.com/2163
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Rewrite performed with this command:
sed -i '' 's_code.google.com/p/go\._golang.org/x/_g' \
$(grep -lr 'code.google.com/p/go.' *)
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/170920043
Also:
- increase sparsity of sets in benchmarks.
- removed TODO in forEach. Subword masks had no benefit.
- minor cleanup.
LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/103470049
This consistently yields better performance with go/pointer.
Also: return int not word from ntz().
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/97570044
(I forgot about this when we added support for negative elements generally.)
We use floating point for negative numbers. The order of the
output is reversed from the previous (little-endian) behaviour
since it makes for more readable floating point.
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/95570043
This is both easier to read and 25% shorter (helpful when
using String() as a map key for interning sets).
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/96370045
intsets.Sparse is a sparse bit vector. It uses space proportional
to the number of elements, not the maximum element (as is the case for a dense bit vector).
A forthcoming CL will make use of it in go/pointer, where it reduces
solve time by 78%. A similar representation is used for Andersen's
analysis in gcc and LLVM.
+ Tests.
LGTM=sameer, crawshaw, gri
R=gri
CC=crawshaw, golang-codereviews, sameer
https://golang.org/cl/10837043
