// Copyright 2009 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 math // This table might overflow 127-bit exponent representations. // In that case, truncate it after 1.0e38. var pow10tab [70]float64 // Pow10 returns 10**e, the base-10 exponential of e. func Pow10(e int) float64 { if e <= -325 { return 0 } else if e > 309 { return Inf(1) } if e < 0 { return 1 / Pow10(-e) } if e < len(pow10tab) { return pow10tab[e] } m := e / 2 return Pow10(m) * Pow10(e-m) } func init() { pow10tab[0] = 1.0e0 pow10tab[1] = 1.0e1 for i := 2; i < len(pow10tab); i++ { m := i / 2 pow10tab[i] = pow10tab[m] * pow10tab[i-m] } }