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// 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.
* it is important to get all one can from this
* routine since it is used in atof to scale numbers.
* the presumption is that GO converts fp numbers better
* than multipication of lower powers of 10.
*/
var pow10tab [70]float64
// Pow10 returns 10**x, the base-10 exponential of x.
func Pow10(e int) float64 {
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];
}
}
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