diff options
Diffstat (limited to '')
-rw-r--r-- | dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/shootout/spectral-norm.go | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/shootout/spectral-norm.go b/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/shootout/spectral-norm.go new file mode 100644 index 0000000..fb41051 --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/shootout/spectral-norm.go @@ -0,0 +1,96 @@ +//go:build ignore +// +build ignore + +/* +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + + * Neither the name of "The Computer Language Benchmarks Game" nor the + name of "The Computer Language Shootout Benchmarks" nor the names of + its contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. +*/ + +/* The Computer Language Benchmarks Game + * http://shootout.alioth.debian.org/ + * + * contributed by The Go Authors. + * Based on spectral-norm.c by Sebastien Loisel + */ + +package main + +import ( + "flag" + "fmt" + "math" +) + +var n = flag.Int("n", 2000, "count") + +func evalA(i, j int) float64 { return 1 / float64(((i+j)*(i+j+1)/2 + i + 1)) } + +type Vec []float64 + +func (v Vec) Times(u Vec) { + for i := 0; i < len(v); i++ { + v[i] = 0 + for j := 0; j < len(u); j++ { + v[i] += evalA(i, j) * u[j] + } + } +} + +func (v Vec) TimesTransp(u Vec) { + for i := 0; i < len(v); i++ { + v[i] = 0 + for j := 0; j < len(u); j++ { + v[i] += evalA(j, i) * u[j] + } + } +} + +func (v Vec) ATimesTransp(u Vec) { + x := make(Vec, len(u)) + x.Times(u) + v.TimesTransp(x) +} + +func main() { + flag.Parse() + N := *n + u := make(Vec, N) + for i := 0; i < N; i++ { + u[i] = 1 + } + v := make(Vec, N) + for i := 0; i < 10; i++ { + v.ATimesTransp(u) + u.ATimesTransp(v) + } + var vBv, vv float64 + for i := 0; i < N; i++ { + vBv += u[i] * v[i] + vv += v[i] * v[i] + } + fmt.Printf("%0.9f\n", math.Sqrt(vBv/vv)) +} |