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