mirror of
https://github.com/golang/go
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45ca9f7a9e
parsing and printing to new syntax. Use -oldparser to parse the old syntax, use -oldprinter to print the old syntax. 2) Change default gofmt formatting settings to use tabs for indentation only and to use spaces for alignment. This will make the code alignment insensitive to an editor's tabwidth. Use -spaces=false to use tabs for alignment. 3) Manually changed src/exp/parser/parser_test.go so that it doesn't try to parse the parser's source files using the old syntax (they have new syntax now). 4) gofmt -w src misc test/bench 5th and last set of files. R=rsc CC=golang-dev https://golang.org/cl/180050
94 lines
2.5 KiB
Go
94 lines
2.5 KiB
Go
/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of "The Computer Language Benchmarks Game" nor the
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name of "The Computer Language Shootout Benchmarks" nor the names of
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its contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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/* The Computer Language Benchmarks Game
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* http://shootout.alioth.debian.org/
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*
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* contributed by The Go Authors.
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* Based on spectral-norm.c by Sebastien Loisel
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*/
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package main
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import (
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"flag"
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"fmt"
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"math"
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)
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var n = flag.Int("n", 2000, "count")
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func evalA(i, j int) float64 { return 1 / float64(((i+j)*(i+j+1)/2 + i + 1)) }
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type Vec []float64
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func (v Vec) Times(u Vec) {
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for i := 0; i < len(v); i++ {
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v[i] = 0
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for j := 0; j < len(u); j++ {
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v[i] += evalA(i, j) * u[j]
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}
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}
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}
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func (v Vec) TimesTransp(u Vec) {
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for i := 0; i < len(v); i++ {
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v[i] = 0
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for j := 0; j < len(u); j++ {
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v[i] += evalA(j, i) * u[j]
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}
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}
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}
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func (v Vec) ATimesTransp(u Vec) {
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x := make(Vec, len(u))
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x.Times(u)
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v.TimesTransp(x)
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}
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func main() {
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flag.Parse()
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N := *n
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u := make(Vec, N)
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for i := 0; i < N; i++ {
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u[i] = 1
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}
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v := make(Vec, N)
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for i := 0; i < 10; i++ {
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v.ATimesTransp(u)
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u.ATimesTransp(v)
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}
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var vBv, vv float64
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for i := 0; i < N; i++ {
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vBv += u[i] * v[i]
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vv += v[i] * v[i]
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}
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fmt.Printf("%0.9f\n", math.Sqrt(vBv/vv))
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}
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