77 lines
1.7 KiB
Go
77 lines
1.7 KiB
Go
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package vec
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import "math"
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// Vectorize returns a function g(xs) that applies f to each x in xs.
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//
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// f may be evaluated in parallel and in any order.
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func Vectorize(f func(float64) float64) func(xs []float64) []float64 {
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return func(xs []float64) []float64 {
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return Map(f, xs)
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}
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}
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// Map returns f(x) for each x in xs.
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//
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// f may be evaluated in parallel and in any order.
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func Map(f func(float64) float64, xs []float64) []float64 {
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// TODO(austin) Parallelize
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res := make([]float64, len(xs))
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for i, x := range xs {
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res[i] = f(x)
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}
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return res
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}
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// Linspace returns num values spaced evenly between lo and hi,
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// inclusive. If num is 1, this returns an array consisting of lo.
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func Linspace(lo, hi float64, num int) []float64 {
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res := make([]float64, num)
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if num == 1 {
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res[0] = lo
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return res
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}
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for i := 0; i < num; i++ {
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res[i] = lo + float64(i)*(hi-lo)/float64(num-1)
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}
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return res
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}
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// Logspace returns num values spaced evenly on a logarithmic scale
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// between base**lo and base**hi, inclusive.
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func Logspace(lo, hi float64, num int, base float64) []float64 {
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res := Linspace(lo, hi, num)
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for i, x := range res {
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res[i] = math.Pow(base, x)
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}
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return res
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}
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// Sum returns the sum of xs.
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func Sum(xs []float64) float64 {
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sum := 0.0
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for _, x := range xs {
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sum += x
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}
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return sum
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}
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// Concat returns the concatenation of its arguments. It does not
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// modify its inputs.
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func Concat(xss ...[]float64) []float64 {
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total := 0
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for _, xs := range xss {
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total += len(xs)
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}
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out := make([]float64, total)
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pos := 0
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for _, xs := range xss {
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pos += copy(out[pos:], xs)
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}
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return out
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}
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